<div style="text-align: center;"><span style="font-family: 黑体;"><font color="#ff0000">教科版小学四年级科学上册复习资料</font></span></div><br><div style="text-align: center;"><span style="font-family: 黑体;">第一单元《天气》</span></div><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">1-1.我们每天都能感觉到天气带来的变化,</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">天气影响着地球上的一切生物</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">1-1.</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">天气</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">是指我们居住的地区,在某个时间的</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">大气状况</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">1-1.我们可以通过</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">云量、降水量、气温、风向和风速</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">等天气特征来描述天气。(温度、风向和风速、降水、云量是天气观察中的重要数据)</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">1-2.记录每天各种天气现象的表格叫做</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">天气日历</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">1-2.在我们的天气日历中,一般要记录</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">日期</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">和</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">时间</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">、</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">云量、降水情况,气温、风向和风速。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">如果有云,还要记录云的类型。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">1-2.观察天气应该在每天的</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">同一时间</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">、</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">同一地点</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">1-3.使用温度计时,要等到温度计里的液柱停止上升或下降后,才能读数。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">1-3.</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">气温</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">是指</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">室外阴凉通风</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">地方的温度,这个地方的温度才能反映当地的气温。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">1-3.测量气温时应该选择室外阴凉、通风的地方。每天同一时间、同一地点来测量</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">1-4.风可以通过自然界中的事物来感知,可以用风向和风速来描述。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">1-4.风向是指</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">风吹来的方向</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">。风向可以用风向标来测量,风向标箭头所指的方向就是风向。我们一般用8个方位来描述风向。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">1-4.风的速度是以风每秒行进多少米来计算的。风速仪是测量风速的仪器。气象学家把风速记为13个等级。在我们的天气日历中可以用简化的风速等级来划分风速。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">1-5.降水是天气的一个基本特征,测量记录降水量的单位是毫米。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">1-5.降水的形式很多,常见的有</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">雨、雪、冰雹</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">等。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">1-5.雨量器是测量降水量多少的装置。雨量器的集水漏斗用来收集雨水,容器中雨水的高度值就是降水量。我们可以用</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">直筒透明杯子</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">来做雨量器。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">1-6.云实际上是由无数的</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">小水滴</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">或</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">小冰晶</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">组成的,云可以看作是天上的雾。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">1-6.根据云量的多少,天气可分为</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">晴天、多云和阴天</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">。云在天空中是会变化的,不同的云预示着不同的天气。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">1-6.不同的天气状况怎样划分呢?一种简单的方法是:把天空当做一个圆,</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">平均分成4份</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">,把看到的云量填充到这个圆里,按照</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">云在天空中所占的多少</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">进行区分。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">1-6.气象学家在对云进行描述时,通常根据云高度和形状把云分成三类:</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">积云、层云和卷云。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">1-6.靠近地球表面的扁平层状云是</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">层云</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">,它通常是</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">灰色</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">的。层云变厚,就是雨层云,将会出现</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">毛毛雨、大雨或雪</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">1-6.高于云层,看上去像棉花堆一样的云叫做</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">积云</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">。积云发展成</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">积雨云</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">,形成</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">雷阵雨</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">1-6.纤细的羽状云是</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">卷云</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">,卷云是由</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">微小的冰晶</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">组成。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">1-7.对天气信息进行整理、总结和分析,可以帮助我们</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">认识天气的某些特</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">征,</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">了解天气变化的一些规</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">律。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">1-7.一个月的天气变化</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">不能代表这一年的气候特点</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><br><div style="text-align: center;"><span style="font-family: 黑体;">第二单元《溶解》</span></div><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">2-1.溶解的特征:物质在水中化成了</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">肉眼看不见的微粒</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">,</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">均匀分布在水中</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">,并且不能用</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">沉降</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">或</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">过滤</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">的方法分离出来。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">2-1.过滤实验中用到的器材有:</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">铁架台、漏斗、过滤纸、玻璃棒、烧杯</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">2-1.做过滤实验时,要注意“</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">一贴、两低、三靠</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">”。(一贴:</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">滤纸紧</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">贴</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">漏斗内壁</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">。两低:</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">滤纸</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">低</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">于漏斗边缘,滤液</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">低</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">于滤纸边缘</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">。三靠:</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">倾倒滤液的烧杯紧</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">靠</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">玻璃棒,玻璃棒紧</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">靠</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">三层滤纸,漏斗末端紧</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">靠</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">承接滤液的烧杯内壁</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">。)</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">2-2.高锰酸钾是</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">紫黑色的固体小颗粒</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">,常被用来消毒和防腐,但</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">不能用手直接取</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">,需要用小匙来取。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">2-2.高锰酸钾进入水中时的状态:</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">极少数溶解,沉入水底。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">轻轻摇晃杯子以后:</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">水底的高锰酸钾减少了,杯中的液体变成紫色</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">。 充分搅拌高锰酸钾后:</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">全部溶解、变成了均匀分布、紫色透明的高锰酸钾溶液。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">2-2.观察和区别“物质在水中是否溶解”的方法有:</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">颗粒大小</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">的变化、在水中是否</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">均匀分布</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">、</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">是否有</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">沉定</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">、</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">能否用</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">过滤</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">的方法分离。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">2-3.胶水或洗发液进入水中的状态:先</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">浮在水面</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">,再</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">下沉</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">,然后一缕缕的</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">扩散</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">,轻轻搅拌</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">部分溶解</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">,充分搅拌</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">全部溶解</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">,最后变成胶水或洗发液溶液。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">2-3.食盐、小苏打、高锰酸钾、胶水、洗发液、醋、酒精都</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">能溶解</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">在水中,形成了透明、稳定的</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">溶液</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">,沙、面粉、食用油</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">不能溶解</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">在水中,形成的是</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">混合物</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">2-4.不同的物质在水中的溶解能力是</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">不同的</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">,食盐在水中的溶解能力比小苏打要</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">强</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">2-4.轻轻开启一瓶汽水,用注射器吸出约1/3管汽水,再用橡皮帽封住管口,向外拉注射器的活塞,看到注射器里的</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">气泡变大,变多了</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">,向下推注射器活塞,看到注射器里的</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">气泡变小,变少了</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">2-4.水除了能溶解</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">固体</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">和</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">液体</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">之外,还能少量地溶解氧气、二氧化碳等</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">气体</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">。水中的动物和植物就是靠溶解在水中的氧气进行呼吸的。汽水中的气体是通过加压或化学方法溶解的,所以瓶一打开,气体就冒出来了。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">2-5.</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">切碎、加温、搅拌</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">等方法可以</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; mso-font-kerning:; ">加快</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">物质在水中的溶解。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">2-6.</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; mso-font-kerning:; "> </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">在100毫升水中,食盐溶解的量是有限度的,大约是</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">36克</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">2-6.溶解在水中的食盐能用</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">蒸发</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">的方法把食盐和水分离出来。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">2-7.给杯子中的盐水加热,可以分离食盐和水,需要的材料有:</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">蒸发皿、石棉网、酒精灯、三脚架、火柴、湿抹布</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">2-7.酒精灯的火焰分为</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">外焰、内焰、焰心</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">三个部分,外焰的</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">温度最高</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">,内焰其次,焰心的温度最低。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">2-7.点燃酒精灯时一定要用</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">燃着的火柴</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">,决不能用燃着的酒精灯对火。加热完毕需要熄火时,可用</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">灯帽盖灭</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">,盖灭时需再</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">重盖一次</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">,以避免以后使用时灯帽打不开,绝对禁止用嘴吹灭火!盐能够溶解在水中,也能从水中分离出来,人们就是利用了盐的这个特点,把海水引进盐田,用太阳的热量使海水中的水分蒸发,最后析出盐的结晶。酒精是容易挥发和燃烧的液体,万一有洒出的酒精在灯外燃烧,不要惊慌,可用湿抹布或沙土扑灭。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><br><div style="text-align: center;"><span style="font-family: 黑体;">第三单元《声音》</span></div><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">3-1.我们周围的声音在</span><span style=" font-family:楷体_GB2312; mso-hansi- text-decoration:underline; text-underline:single; mso-font-kerning:; "> </span><span style=" font-family:楷体_GB2312; mso-hansi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">强弱、高低、长短 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">等方面有着不同的特点。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">3-1.音叉是一种</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; "> </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">发声仪器</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; "> </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">,用来</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; "> 调试乐器 和 测试音高 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">3-1.敲击大小不同的两支音叉,小音叉</span><span style=" font-family:楷体_GB2312; mso-hansi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">发出的声音高</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">,大音叉</span><span style=" font-family:楷体_GB2312; mso-hansi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">发出的声音低。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">3-2.一个物体在力的作用下,不断重复地做往返运动,这种运动称为</span><span style=" font-family:楷体_GB2312; mso-hansi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; "> 振动 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">3-2.声音是由 </span><span style=" font-family:楷体_GB2312; mso-hansi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">物体振动 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">产生的。(物体受到外力作用不一定发出声音,只有让它振动才行。如果停止振动声音就会马上停止。)</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">3-2.用击打过的音叉轻轻接触水面,水面会</span><span style=" font-family:楷体_GB2312; mso-hansi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; "> 产生波纹 </span><span style=" font-family:楷体_GB2312; mso-hansi- font-weight:bold; mso-font-kerning:; ">,</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">这说明音叉振动了。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">3-3.声音的强弱可以用</span><span style=" font-family:楷体_GB2312; mso-hansi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; "> 音量 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">来描述。声音的高低可以用 </span><span style=" font-family:楷体_GB2312; mso-hansi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">音高 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">来描述。(音高是描述物体振动快慢的一个量。)</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">3-3.</span><span style="font-family: 楷体_GB2312; ">音量是由物体振动的</span><span style=" font-family:楷体_GB2312; mso-hansi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; "> 幅度 </span><span style="font-family: 楷体_GB2312; ">决定的</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">。</span><span style=" font-family:楷体_GB2312; mso-hansi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">振动幅度越大,声音越强 ;振动幅度越小,声音越弱 。</span><span style=" font-family:楷体_GB2312; mso-hansi- text-decoration:underline; text-underline:single; mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">3-3.</span><span style="font-family: 楷体_GB2312; ">音高是由物体振动的</span><span style=" font-family:楷体_GB2312; mso-hansi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; "> 快慢</span><span style=" font-family:楷体_GB2312; mso-hansi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">(频率) </span><span style="font-family: 楷体_GB2312; ">决定的</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">。</span><span style=" font-family:楷体_GB2312; mso-hansi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">振动越快,发出的声音就越高;振动越慢,发出的声音就越低 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">,</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">3-3.敲击水量不同的玻璃杯,</span><span style=" font-family:楷体_GB2312; mso-hansi- text-decoration:underline; text-underline:single; mso-font-kerning:; "> 水越少声音越高,水越多声音越低 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">3-3.拨弹橡皮筋时,</span><span style=" font-family:楷体_GB2312; mso-hansi- text-decoration:underline; text-underline:single; mso-font-kerning:; "> 皮筋越紧,声音越高;皮筋越松,声音越低 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">。</span><span style=" font-family:楷体_GB2312; mso-hansi- text-decoration:underline; text-underline:single; mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">3-3.拨动琴弦时,</span><span style=" font-family:楷体_GB2312; mso-hansi- text-decoration:underline; text-underline:single; mso-font-kerning:; "> 琴弦越细,声音越高;琴弦越粗,声音越低 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">。</span><span style=" font-family:楷体_GB2312; mso-hansi- text-decoration:underline; text-underline:single; mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">3-3.击打长短不同钉子时,钉子越短</span><span style=" font-family:楷体_GB2312; mso-hansi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">发出的声音越高</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">3-4.在拨动钢尺时,改变尺子伸出桌面的长度,尺子振动时发出的音高</span><span style=" font-family:楷体_GB2312; mso-hansi- text-decoration:underline; text-underline:single; mso-font-kerning:; "> 也会改变 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">,因为</span><span style=" font-family:楷体_GB2312; mso-hansi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">尺子振动的快慢改变了</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">3-4.尺子伸出桌面越短,</span><span style=" font-family:楷体_GB2312; mso-hansi- text-decoration:underline; text-underline:single; mso-font-kerning:; "> 发出的声音越</span><span style=" font-family:楷体_GB2312; mso-hansi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; "> 高 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">;尺子伸出桌面越长,</span><span style=" font-family:楷体_GB2312; mso-hansi- text-decoration:underline; text-underline:single; mso-font-kerning:; "> 发出的声音越</span><span style=" font-family:楷体_GB2312; mso-hansi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; "> 低 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">3-5.声音以</span><span style=" font-family:楷体_GB2312; mso-hansi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; "> 波 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">的形式传播,当声波遇到物体时,会使</span><span style=" font-family:楷体_GB2312; mso-hansi- text-decoration:underline; text-underline:single; mso-font-kerning:; "> </span><span style=" font-family:楷体_GB2312; mso-hansi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">物体产生振动 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">,声音就是这样通过各种物质,从</span><span style=" font-family:楷体_GB2312; mso-hansi- text-decoration:underline; text-underline:single; mso-font-kerning:; "> 一个地方传播到另外一个地方 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">的。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">3-5.声音在不同物体中传播的情况是</span><span style=" font-family:楷体_GB2312; mso-hansi- text-decoration:underline; text-underline:single; mso-font-kerning:; "> 不一样的 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">3-5.空气是传播声音的重要物质,在真空的环境中</span><span style=" font-family:楷体_GB2312; mso-hansi- text-decoration:underline; text-underline:single; mso-font-kerning:; "> 不能传播 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">声音。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">3-5.在月球上,由于</span><span style=" font-family:楷体_GB2312; mso-hansi- text-decoration:underline; text-underline:single; mso-font-kerning:; "> 没有空气 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">,即没有可以传播振动的物质,两个人即使相隔不远,也</span><span style=" font-family:楷体_GB2312; mso-hansi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">听不到到声音、不能互相通话 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">,必须要使用无线电设备。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">3-6.我们的耳朵可分为</span><span style=" font-family:楷体_GB2312; mso-hansi- text-decoration:underline; text-underline:single; mso-font-kerning:; "> </span><span style=" font-family:楷体_GB2312; mso-hansi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">外耳、中耳、内耳 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">。</span><span style="font-family: 楷体_GB2312; ">外耳的</span><span style="font-family: 楷体_GB2312; text-decoration: underline; "> 耳廓 </span><span style="font-family: 楷体_GB2312; ">把收集到的声音通过</span><span style="font-family: 楷体_GB2312; text-decoration: underline; "> 耳道 </span><span style="font-family: 楷体_GB2312; ">传到鼓膜,引起</span><span style="font-family: 楷体_GB2312; text-decoration: underline; "> 鼓膜的振动 </span><span style="font-family: 楷体_GB2312; ">,这种振动信号传递到大脑,通过大脑的加工,我们就能听到各种各样的声音了。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">3-6.鼓膜很薄很有弹性,即使是很轻的声音,它都会</span><span style=" font-family:楷体_GB2312; mso-hansi- text-decoration:underline; text-underline:single; mso-font-kerning:; "> 产生振动 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">3-6.一个振动的物体会使它周围的空气发生振动,振动的空气到达我们的耳朵,引起</span><span style=" font-family:楷体_GB2312; mso-hansi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; "> 鼓膜 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">的振动。耳中的</span><span style=" font-family:楷体_GB2312; mso-hansi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; "> 听小骨 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">再将振动传到充满液体的内耳,引起液体的振动,液体的振动刺激</span><span style=" font-family:楷体_GB2312; mso-hansi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; "> 听觉神经 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">——产生了信号,大脑接受了听觉神经传过来的信号,我们便感受到了声音。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">3-7.耳朵是我们的</span><span style=" font-family:楷体_GB2312; mso-hansi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; "> 听觉器官 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">,需要精心呵护。减少有害的声音,对于保护我们的听力和身体健康是很重要的。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">3-7.噪音对人的伤害:声音</span><span style=" font-family:楷体_GB2312; mso-hansi- text-decoration:underline; text-underline:single; mso-font-kerning:; "> 过高过强 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">,损伤我们的听力,所以我们要尽量远离这些声音,有时需要捂住耳朵或戴上保护装置 。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">3-7.保护我们听力的方法有:</span><span style=" font-family:楷体_GB2312; mso-hansi- text-decoration:underline; text-underline:single; mso-font-kerning:; "> </span><span style=" font-family:楷体_GB2312; mso-hansi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">远离噪声 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">、</span><span style=" font-family:楷体_GB2312; mso-hansi- text-decoration:underline; text-underline:single; mso-font-kerning:; "> </span><span style=" font-family:楷体_GB2312; mso-hansi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">控制物体发声 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">(资料:声带越紧,声音越高。成年女子的声带长大约为</span><span style=" font-family:楷体_GB2312; mso-hansi- display:none; mso-hide:all; mso-font-kerning:; background:; mso-highlight:; "><</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">11毫米</span><span style=" font-family:楷体_GB2312; mso-hansi- display:none; mso-hide:all; mso-font-kerning:; background:; mso-highlight:; ">></span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">,成年男子的声带长大约为</span><span style=" font-family:楷体_GB2312; mso-hansi- display:none; mso-hide:all; mso-font-kerning:; background:; mso-highlight:; "><</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">15毫米</span><span style=" font-family:楷体_GB2312; mso-hansi- display:none; mso-hide:all; mso-font-kerning:; background:; mso-highlight:; ">></span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; ">,所以,成年男子的声音通常比成年的女子声音低。)</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-font-kerning:; "></span><br><br><br><div style="text-align: center;"><span style="font-family: 黑体;">第四单元《我们的身体》</span></div><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">4-1.从外形上看,人的身体一般可以分为 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">头</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">、</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">颈</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">、</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">躯干</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">、</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">四肢 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">四部分组成。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">4-1.身体能够做很多工作,工作时总是由多个部位 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">同时参与</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">、</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">共同完成</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">4-1.人体的外部特点可以 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">直接观察 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">,内部特点可以 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">借助一些工具 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">,也可以用</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">看、听、闻、摸</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">的方法感觉。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">4-2.我们的身体里有一个支架,这就是 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">骨骼 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">骨骼 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">支撑着 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">我们的身体, </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">保护着 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">我们的内脏器官,使我们能进行各种各样的</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">活动</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">。骨骼不能独立运动。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">4-2.人体的活动由</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">骨骼</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">、</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">关节</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">和</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">肌肉</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">共同完成,不同的运动形式,骨骼、关节和肌肉的</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">组合形式也不同</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">4-2.经常参加体育锻炼,能使我们的</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">骨骼粗壮</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">,</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">肌肉发达</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">,</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">关节灵活</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">4-3.人的呼吸器官有:</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">鼻腔</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">、</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">气管</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">、</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">支气管 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">、 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">肺 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">等。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">4-3.人的呼吸实际上是在进行着</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">气体交换</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">,使</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">氧气</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">进入血液</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">,同时</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">排出</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">二氧化碳</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">4-3.为什么运动时呼吸会加快?</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">因为人体运动的过程中,需要</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">消耗大量的氧气,</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">所以呼吸的次数要比平时多,以便呼出和吸入比平时多的气体。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">4-3.经常锻炼身体,会</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">提高我们的呼吸能力,增大肺活量,获得更多的氧气</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">4-3.肺活量是指一次</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">尽力吸气后,再尽力呼出的</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">气体总量</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; "></span><br><br><span style="font-family: 楷体_GB2312; ">4-4.人体需要的氧气</span><span style="font-family: 楷体_GB2312; text-decoration: underline; ">由 </span><span style="font-family: 楷体_GB2312; font-weight: bold; text-decoration: underline; ">肺 </span><span style="font-family: 楷体_GB2312; text-decoration: underline; ">吸入后进入血液</span><span style="font-family: 楷体_GB2312; ">,再由 </span><span style="font-family: 楷体_GB2312; font-weight: bold; text-decoration: underline; ">心脏 </span><span style="font-family: 楷体_GB2312; text-decoration: underline; ">通过 </span><span style="font-family: 楷体_GB2312; font-weight: bold; text-decoration: underline; ">血管 </span><span style="font-family: 楷体_GB2312; text-decoration: underline; ">输送到身体的各个部位,</span><span style="font-family: 楷体_GB2312; ">同时收集</span><span style="font-family: 楷体_GB2312; text-decoration: underline; ">二氧化碳</span><span style="font-family: 楷体_GB2312; ">等废物,再排出体外。</span><span style="font-family: 楷体_GB2312; "></span><br><br><span style="font-family: 楷体_GB2312; ">4-4.心脏的心肌收缩,血液</span><span style="font-family: 楷体_GB2312; text-decoration: underline; ">离开心脏</span><span style="font-family: 楷体_GB2312; ">,心肌舒张,血液</span><span style="font-family: 楷体_GB2312; text-decoration: underline; ">回到心脏</span><span style="font-family: 楷体_GB2312; ">。</span><span style="font-family: 楷体_GB2312; "></span><br><br><span style="font-family: 楷体_GB2312; ">4-4.为什么运动时心跳会加快?</span><span style="font-family: 楷体_GB2312; text-decoration: underline; ">因为伴随着身体运动量的增加,人需要更多氧气,心跳也就逐渐加快,以便输送出更多的血液。</span><span style="font-family: 楷体_GB2312; text-decoration: underline; "></span><br><br><span style="font-family: 楷体_GB2312; ">4-5.人体的消化器官主要包括 </span><span style="font-family: 楷体_GB2312; font-weight: bold; text-decoration: underline; ">口腔</span><span style="font-family: 楷体_GB2312; text-decoration: underline; ">、</span><span style="font-family: 楷体_GB2312; font-weight: bold; text-decoration: underline; ">食管</span><span style="font-family: 楷体_GB2312; text-decoration: underline; ">、</span><span style="font-family: 楷体_GB2312; font-weight: bold; text-decoration: underline; ">胃</span><span style="font-family: 楷体_GB2312; text-decoration: underline; ">、</span><span style="font-family: 楷体_GB2312; font-weight: bold; text-decoration: underline; ">小肠 </span><span style="font-family: 楷体_GB2312; text-decoration: underline; ">和 </span><span style="font-family: 楷体_GB2312; font-weight: bold; text-decoration: underline; ">大肠</span><span style="font-family: 楷体_GB2312; ">。食物被食管 </span><span style="font-family: 楷体_GB2312; font-weight: bold; text-decoration: underline; ">运输 </span><span style="font-family: 楷体_GB2312; ">到</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">胃里,在胃里被进一步</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; "> </span><span style="font-family: 楷体_GB2312; font-weight: bold; text-decoration: underline; ">磨碎 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">和 </span><span style="font-family: 楷体_GB2312; font-weight: bold; text-decoration: underline; ">分解 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">的,在小肠里被 </span><span style="font-family: 楷体_GB2312; font-weight: bold; text-decoration: underline; ">吸收 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style="font-family: 楷体_GB2312; ">4-5.</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">如果食物在体内消化得好,我们就会吸收</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">更多的营养</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">,为骨骼、肌肉的生长提供养料。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">4-6.口腔是食物消化开始的地方,是由</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; "> </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">牙齿</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">、</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">舌头</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">、</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">唾液 </span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">共同完成的。牙齿按形状给牙齿分类,可分为</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">门齿</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">(我有 个)、</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">犬齿</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">(我有 个)、</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; text-decoration:underline; text-underline:single; mso-font-kerning:; ">臼齿</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">(我有 个)。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">4-6.老人们常说“细嚼慢咽”的道理是</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">牙齿将食物磨碎,以利于食物在体内消化</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">4-6.如果牙齿不好,消化就会</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">受到影响</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">,还会</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">影响整个身体的运动</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">4-7.人的一切活动都需要依靠</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">身体各个器官的协同工作</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">才能完成。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">4-7.人体活动需要的能量来自于我们</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">每天所吃的食物</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; "></span><br><br><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">4-7.人体的每个消化器官都在各自的功能,都</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- text-decoration:underline; text-underline:single; mso-font-kerning:; ">需要我们爱护</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- mso-font-kerning:; ">。</span><span style=" font-family:楷体_GB2312; mso-hansi- mso-bidi- font-weight:bold; mso-font-kerning:; "></span><br><br>
四年级上