<div style="text-align: center;"><strong><font color="#ff0000">六年级科学第一单元复习资料</font></strong></div><br><div style="text-align: center;">姓名：_______ 班级：________学号：__________</div><br><span><strong>一、使用工具</strong></span><span></span><br><br><span>1</span><span>．</span><span style=" text-decoration: underline; "> 机械 </span><span>是能使我们</span><span style=" text-decoration: underline; ">省力或方便</span><span>的装置。</span><span></span><br><br><span>2</span><span>．螺丝刀、钉锤、剪刀这些机械构造很简单，又叫</span><span style=" text-decoration: underline; "> 简单机械 </span><span>。</span><span></span><br><br><span>3．用</span><span style=" text-decoration: underline; ">螺丝刀</span><span>可以比较方便的把</span><span style=" text-decoration: underline; ">螺丝钉</span><span>从木头中取出，用</span><span style=" text-decoration: underline; ">羊角榔头</span><span>可以比较方便的把</span><span style=" text-decoration: underline; ">铁钉</span><span>从木头中取出。不同的工具有不同的用途。</span><span></span><br><br><span><strong>二、杠杆的科学</strong></span><span></span><br><br><span>1．</span><span>像撬棍这样的简单机械叫做</span><span style=" text-decoration: underline; "> 杠杆 </span><span>。</span><span></span><br><br><span>2．</span><span>杠杆上有三个重要的位置：支撑着杠杆，使杠杆能围绕着转动的位置叫</span><span style=" text-decoration: underline; "> 支点 </span><span>；在杠杆上用力的位置叫</span><span style=" text-decoration: underline; "> 用力点 </span><span>；杠杆克服阻力的位置叫</span><span style=" text-decoration: underline; "> 阻力点 </span><span>。</span><span></span><br><br><span>3．</span><span>当阻力点到支点的距离</span><span style=" text-decoration: underline; ">小于</span><span>用力点到支点的距离时，杠杆</span><span style=" text-decoration: underline; "> 省力 </span><span>；当阻力点到支点的距离</span><span style=" text-decoration: underline; ">大于</span><span>用力点到支点的距离时，杠杆</span><span style=" text-decoration: underline; "> 费力</span><span>；当阻力点到支点的距离</span><span style=" text-decoration: underline; ">等于</span><span>用力点到支点的距离时，杠杆</span><span style=" text-decoration: underline; "> 不省力也不费力 </span><span>。</span><span></span><br><br><span>4．</span><span style=" text-decoration: underline; ">杠杆尺</span><span>上有</span><span style=" text-decoration: underline; ">支点</span><span>，左右两边都有到支点距离的标记，是研究杠杆作用的好工具。</span><span></span><br><br><span>5．用三种不同的方法挂钩码，使</span><span style=" text-decoration: underline; ">杠杆尺</span><span>保持平衡，把你的方法在下图画出来。 </span><span></span><br><br><span><strong>三、杠杆类工具的研究</strong></span><span></span><br><br><span>1．省力的是（</span><span style=" text-decoration: underline; ">铁片、羊角榔头、老虎钳、开瓶器 </span><span>），费力的是（</span><span style=" text-decoration: underline; ">火钳、镊子</span><span>）。</span><span></span><br><br><span>2．常用的杠杆类工具中</span><span style=" text-decoration: underline; ">羊角榔头、老虎钳、开瓶器</span><span>是</span><span style=" text-decoration: underline; ">省力</span><span>杠杆；</span><span style=" text-decoration: underline; ">火钳、筷子、镊子</span><span>是</span><span style=" text-decoration: underline; ">费力</span><span>杠杆；</span><span style=" text-decoration: underline; ">跷跷板、天平、订书器</span><span>是</span><span style=" text-decoration: underline; ">不省力也不费力</span><span>杠杆</span><span>。有些</span><span>杠杆类工具设计成费力的是</span><span style=" text-decoration: underline; ">因为它有方便的好处</span><span>（如：镊子、钓鱼竿等）。</span><span></span><br><br><span>3．“秤砣虽小，能压千斤”，那是</span><span style=" text-decoration: underline; ">杆秤</span><span>利用了</span><span style=" text-decoration: underline; "> 杠杆 </span><span>原理的结果（提绳是</span><span style=" text-decoration: underline; ">支点</span><span>，秤砣是</span><span style=" text-decoration: underline; ">用力点</span><span>，称重物处是</span><span style=" text-decoration: underline; ">阻力点</span><span>）。</span><span></span><br><br><span>4．我们身体上的前臂骨像是一根杠杆，肘关节是</span><span style=" text-decoration: underline; ">支点</span><span>，手握物体处是</span><span style=" text-decoration: underline; ">阻力点</span><span>，上臂的肱二头肌处就是</span><span style=" text-decoration: underline; ">用力点</span><span>。</span><span></span><br><br><span>5．阿基米德曾说：“只要在宇宙中给我一个支点，我能用一根长长的棍子把地球撬起来。”这里的</span><span style=" text-decoration: underline; ">棍子相当于杠杆</span><span>。</span><span></span><br><br><span><strong>四、轮轴的秘密</strong></span><span></span><br><br><span>1．像水龙头这样，轮子和轴</span><span style=" text-decoration: underline; ">固定在一起转动</span><span>的机械，叫做</span><span style=" text-decoration: underline; "> 轮轴 </span><span>。螺丝刀是轮轴类工具，它的刀柄是</span><span style=" text-decoration: underline; "> 轮 </span><span>，刀杆是</span><span style=" text-decoration: underline; "> 轴 </span><span>。</span><span></span><br><br><span>2</span><span>．在轮上用力带动轴运动时</span><span style=" text-decoration: underline; "> 省 </span><span>力；在轴上用力带动轮运动时</span><span style=" text-decoration: underline; "> 费 </span><span>力。</span><span></span><br><br><span>3</span><span>．轮轴可以</span><span style=" text-decoration: underline; "> 省 </span><span>力，</span><span style=" text-decoration: underline; ">轮越大</span><span>，用轮带动轴转动就越</span><span style=" text-decoration: underline; "> 省 </span><span>力。所以螺丝刀的刀柄总是比刀杆要</span><span style=" text-decoration: underline; "> 粗 </span><span>一些。</span><span></span><br><br><span>4．扳手套在螺帽上组成了</span><span style=" text-decoration: underline; "> </span><span style=" text-decoration: underline; ">轮轴</span><span style=" text-decoration: underline; "> </span><span>，这时整个扳手是</span><span style=" text-decoration: underline; "> 轮 </span><span>，螺帽部分是</span><span style=" text-decoration: underline; "> 轴 </span><span>。</span><span></span><br><br><span>5．生活中的轮轴：</span><span style=" text-decoration: underline; ">水龙头、门锁把手、汽车方向盘、扳手、辘轳等</span><span>。</span><span></span><br><br><span><strong>五、定滑轮和动滑轮</strong></span><span></span><br><br><span>1</span><span>．像</span><span style=" text-decoration: underline; ">旗杆顶部的滑轮</span><span>那样，</span><span style=" text-decoration: underline; ">固定</span><span>在一个位置转动而不移动的滑轮叫做</span><span style=" text-decoration: underline; "> 定滑轮 </span><span>；定滑轮可以</span><span style=" text-decoration: underline; "> 改变用力方向 </span><span>，但不能</span><span style=" text-decoration: underline; "> 省力 </span><span> 。</span><span></span><br><br><span>2</span><span>．像塔吊的吊钩上可以随着重物一起</span><span style=" text-decoration: underline; ">移动</span><span>的滑轮叫做</span><span style=" text-decoration: underline; "> 动滑轮 </span><span> ；动滑轮可以 </span><span style=" text-decoration: underline; ">省力 </span><span>，但不能</span><span style=" text-decoration: underline; "> 改变用力方向 </span><span>。</span><span></span><br><br><span>3．</span><span>动滑轮可以省力，但不能改变用力方向。</span><span></span><br><br><span>*力的大小用</span><span style=" text-decoration: underline; ">测力计</span><span>来测量，</span><span style=" text-decoration: underline; ">牛顿是力的单位，用字母“N”表示</span><span>。</span><span></span><br><br><span><strong>六、滑轮组</strong></span><span></span><br><br><span>1．</span><span>把定滑轮和动滑轮组合在一起使用，就构成了</span><span style=" text-decoration: underline; ">滑轮组</span><span>。使用滑轮组既能</span><span style=" text-decoration: underline; ">省力</span><span>，又能</span><span style=" text-decoration: underline; "> 改变用力方向 </span><span>。</span><span></span><br><br><span>2．</span><span>一个定滑轮和一个动滑轮组合在一起为一个</span><span style=" text-decoration: underline; "> 最简单的滑轮组 </span><span>，滑轮组的组数越多，就越</span><span style=" text-decoration: underline; "> 省力 </span><span>。</span><span></span><br><br><span>3．</span><span style=" text-decoration: underline; ">起重机</span><span>运用了滑轮组。</span><span></span><br><br><span>4．</span><span> ①名称：</span><span style=" text-decoration: underline; ">定滑轮</span><span>_ ②名称：</span><span style=" text-decoration: underline; ">动滑轮</span><span> ③名称：</span><span style=" text-decoration: underline; ">滑轮组</span><span> ④名称：</span><span style=" text-decoration: underline; ">滑轮组</span><span> </span><span></span><br><br><span>所起的作用： 所起的作用： 所起的作用： 所起的作用：</span><span></span><br><br><span> </span><span style=" text-decoration: underline; ">改变用力方向</span><span> </span><span style=" text-decoration: underline; ">能省力</span><span> </span><span style=" text-decoration: underline; ">既能省力</span><span> </span><span style=" text-decoration: underline; ">既能省力</span><span></span><br><br><span style=" text-decoration: underline; ">不能省力</span><span> </span><span style=" text-decoration: underline; ">不能改变用力方向</span><span> </span><span style=" text-decoration: underline; ">又能改变用力方向</span><span> </span><span style=" text-decoration: underline; ">又能改变用力方向</span><span></span><br><br><span>如果分别用它们提起相同重量的物品50千克，最省力的是（ ④ ），其次是（ ② 、③ ），不省力的是（ ① ）。</span><span></span><br><br><span><strong>七、斜面的作用</strong></span><span></span><br><br><span>1</span><span>．像搭在汽车车厢上的木板那样的简单机械，叫做</span><span style=" text-decoration: underline; "> 斜面 </span><span>。</span><span></span><br><br><span>2</span><span>．斜面能</span><span style=" text-decoration: underline; "> 省 </span><span>力，斜面的坡度越</span><span style=" text-decoration: underline; "> 小 </span><span>越省力，坡度越</span><span style=" text-decoration: underline; "> 大 </span><span>越不省力。</span><span></span><br><br><span>3．生活中应用斜面的地方很多，如</span><span style=" text-decoration: underline; "> “S” 形的盘山公路、各种斜坡、各种刀刃、螺丝钉的螺纹，高架桥的引桥等 </span><span>。</span><span></span><br><br><span>4</span><span>．螺丝钉的螺纹是</span><span style=" text-decoration: underline; ">斜面</span><span>的变形。同样粗细的螺丝钉，</span><span style=" text-decoration: underline; ">螺纹越密</span><span>，旋进木头时越</span><span style=" text-decoration: underline; "> 省力 </span><span>。</span><span></span><br><br><span>5． 研究的问题：</span><span style=" text-decoration: underline; ">斜面的坡度对省力多少有影响吗？</span><span></span><br><br><span>我的假设：</span><span style=" text-decoration: underline; "> 斜面的坡度对省力多少有影响；斜面的坡度越小越省力</span><span>。</span><span></span><br><br><span>需要改变的条件：</span><span style=" text-decoration: underline; "> 斜面的坡度大小（木块的高低） </span><span></span><br><br><span>不改变的条件： </span><span style=" text-decoration: underline; "> 同一个重物，同一块木板，提升重物的速度； </span><span></span><br><br><span>实验方法：（1）</span><span style=" text-decoration: underline; ">把一块木板分别搭在高低不同的木块上，做成几个坡度不同的斜面；</span><span> （2）</span><span style=" text-decoration: underline; ">用测力计勾住重物，用同样的速度沿不同坡度的斜面提升重物；</span><span>（3）</span><span style=" text-decoration: underline; ">记录下在每种斜面上用力的大小，并进行比较。</span><span></span><br><br><span><strong>八、自行车上的简单机械</strong></span><span></span><br><br><span>1</span><span>．自行车运用了</span><span style=" text-decoration: underline; "> 杠杆（如：刹车、车铃的按钮） </span><span>、</span><span style=" text-decoration: underline; "> 轮轴 （如：把手、脚蹬） </span><span>、</span><span style=" text-decoration: underline; "> 斜面（如：螺丝钉） </span><span>等简单机械的原理。这些简单机械起到</span><span style=" text-decoration: underline; ">省力或方便</span><span>的作用。</span><span></span><br><br><span>2</span><span>．自行车上齿轮转动的快慢与齿轮大小的关系是：大齿轮带动小齿轮转动时，小齿轮转动比大齿轮</span><span style=" text-decoration: underline; "> 快 </span><span>；小齿轮带动大齿轮转动时，大齿轮转动比小齿轮</span><span style=" text-decoration: underline; "> 慢 </span><span>。</span><span></span><br><br><span>* 综合：请把下面物品和应用的简单机械原理用线连起来。</span><span></span><br><br><span>斜面</span><span> </span><span> </span><span> 轮轴</span><span> </span><span> </span><span> </span><span> 杠杆</span><span> </span><span> </span><span> </span><span> 滑轮</span><span></span><br><br><span>螺丝刀</span><span> </span><span>镊子</span><span> </span><span>螺丝钉</span><span> </span><span>水龙头</span><span> </span><span>起重机</span><span></span><br><br><br><div style="text-align: center;"><strong><font color="#38761d">第二单元 形状与结构</font></strong></div><br><span><strong>一、抵抗弯曲</strong></span><span></span><br><br><span>1</span><span>．房屋、桥梁结构中有直立的</span><span style=" text-decoration: underline; ">“柱子”</span><span>和横放的</span><span style=" text-decoration: underline; ">“横梁”</span><span>，横梁比柱子容易弯曲和断裂，所以要提高横梁的抗弯曲能力。</span><span></span><br><br><span>2</span><span>．提高材料的抗弯曲能力，我们可以通过</span><span style=" text-decoration: underline; ">增加材料的宽度</span><span>，还可以</span><span style=" text-decoration: underline; ">增加材料的厚度</span><span>或</span><span style=" text-decoration: underline; ">改变材料的形状</span><span>。</span><span></span><br><br><span>3</span><span>．纸的宽度增加，抗弯曲能力也会</span><span style=" text-decoration: underline; ">增加</span><span>；纸的厚度增加，抗弯曲能力会</span><span style=" text-decoration: underline; ">大大增加</span><span>。</span><span></span><br><br><span>4．研究的问题：</span><span style=" text-decoration: underline; ">纸的宽度与抗弯曲能力的大小有关吗？</span><span></span><br><br><span>实验材料：</span><span style=" text-decoration: underline; ">两叠书、三张A4纸、若干个垫圈 </span><span></span><br><br><span>实验假设：</span><span style=" text-decoration: underline; ">有关，纸越宽的抗弯曲能力越大 </span><span></span><br><br><span>实验步骤：</span><span style=" text-decoration: underline; ">①把两叠书当作桥墩，放上一张纸，最多能承受几个垫圈；②放两张纸，最多能承受几个垫圈；③放三张纸，最多能承受几个垫圈；④比较结果，得出结论。</span><span></span><br><br><span>实验中应控制不变的量：</span><span style=" text-decoration: underline; "> 纸的宽度 </span><span>；不变的量有：</span><span style=" text-decoration: underline; "> 桥墩的高度、宽度，每张纸的大小，每个垫圈的重量，纸被压垮的程度。</span><span></span><br><br><span style=" text-decoration: underline; ">在这个实验中我们用</span><span style=" text-decoration: underline; ">承载垫圈的个数</span><span style=" text-decoration: underline; ">表示纸梁的抗弯曲能力。</span><span></span><br><br><span><strong>二、形状与抗弯曲能力</strong></span><span></span><br><br><span>1</span><span>．把薄板形材料弯折成“</span><span>V</span><span>”“</span><span>L</span><span>”“</span><span>U</span><span>”“</span><span>T</span><span>”或“工”字等形状，虽然减少了材料的</span><span style=" text-decoration: underline; ">宽度</span><span>但却增加了材料的</span><span style=" text-decoration: underline; ">厚度</span><span>，增加</span><span style=" text-decoration: underline; ">厚度</span><span>是能</span><span style=" text-decoration: underline; ">大大增强</span><span>材料抗弯曲能力的。</span><span></span><br><br><span>2</span><span>．一般情况下横梁是立着放的，因为横梁立着放虽然减少材料</span><span style=" text-decoration: underline; ">宽度</span><span>，但增加了</span><span style=" text-decoration: underline; ">厚度</span><span>，</span><span style=" text-decoration: underline; ">大大增强</span><span>了横梁的抗弯曲能力。</span><span></span><br><br><span>3</span><span>．瓦楞纸板的结构为什么能使柔软的纸变坚硬了了？</span><span style=" text-decoration: underline; ">因为瓦楞纸中间的结构是是W是形，虽然减少了材料的宽度，但增加了厚度，就大大增强了材料的抗弯曲能力。</span><span></span><br><br><span><strong>三、拱形的力量</strong></span><span></span><br><br><span>1</span><span>．拱形承载重量时，能把压力</span><span style=" text-decoration: underline; ">向下</span><span>和</span><span style=" text-decoration: underline; ">向外</span><span>传递给相邻的部分，拱形各部分相互挤压结合得更加紧密。拱形受压会产生一个</span><span style=" text-decoration: underline; ">向外推的力</span><span>，抵住了这个力，</span><span style=" text-decoration: underline; ">拱就能承载很大的重量</span><span>。</span><span></span><br><br><span>2．抵住</span><span style=" text-decoration: underline; ">拱足</span><span>，能使拱的形状保持不变，拱就能承载更大的重量。</span><span></span><br><br><span><strong>四、找拱形</strong></span><span></span><br><br><span>1．</span><span>圆顶形可以看成</span><span style=" text-decoration: underline; ">拱形的组合</span><span>，它有拱形承载压力大的优点，而且</span><span style=" text-decoration: underline; ">不产生向外的推力</span><span>。</span><span></span><br><br><span>2</span><span>．球形在</span><span style=" text-decoration: underline; ">各个方向上</span><span>都可以看成</span><span style=" text-decoration: underline; ">拱形</span><span>，这使得它比任何形状都要坚固。（如手捏鸡蛋不易碎）</span><span></span><br><br><span>3</span><span>．塑料瓶的</span><span style=" text-decoration: underline; ">上部、底部</span><span>为近似</span><span style=" text-decoration: underline; ">圆顶形</span><span>，</span><span style=" text-decoration: underline; ">中部</span><span>为</span><span style=" text-decoration: underline; ">圆柱形</span><span>。</span><span style=" text-decoration: underline; ">最厚最硬</span><span>的地方在</span><span style=" text-decoration: underline; ">瓶口</span><span>，</span><span style=" text-decoration: underline; ">最薄最软</span><span>的地方在</span><span style=" text-decoration: underline; ">瓶身</span><span>。</span><span></span><br><br><span>4</span><span>．人体的结构非常巧妙。</span><span style=" text-decoration: underline; ">头骨</span><span>近似于</span><span style=" text-decoration: underline; ">球形</span><span>，可以很好的保护大脑；</span><span style=" text-decoration: underline; ">拱形</span><span>的</span><span style=" text-decoration: underline; ">肋骨</span><span>护卫着胸腔中的内脏；人的足骨构成一个拱形——</span><span style=" text-decoration: underline; ">足弓</span><span>，它可以更好的承载人体的重量。</span><span></span><br><br><span>5．生活中的拱形：</span><span style=" text-decoration: underline; ">肋骨、足弓、拱门，拱窗，拱桥</span><span>；圆顶形：</span><span style=" text-decoration: underline; ">龟壳，贝壳</span><span>；球形：</span><span style=" text-decoration: underline; ">蛋壳，果实，头骨。</span><span></span><br><br><span>6．同样多的材料，做成</span><span style=" text-decoration: underline; ">空心的管状</span><span>比做成实心的棒状要粗的多，而且</span><span style=" text-decoration: underline; ">任何方向的抗弯曲力都相同</span><span>，即重量轻、强度高。管状的手臂骨、腿骨，植物的杆、茎，钢管都是应用了这个原理。</span><span></span><br><br><span><strong>五、做框架</strong></span><br><br><span>1</span><span>．像铁塔这样骨架式的构造叫做框架结构。三角形框架具有稳定性的特点。</span><span></span><br><br><span>2．长方形框架、正方体框架加上</span><span style=" text-decoration: underline; ">斜杆</span><span>相当于里面有了三角形，可以起到加固作用。</span><span></span><br><br><span><strong>六、建高塔</strong></span><span></span><br><br><span>1．用</span><span style=" text-decoration: underline; ">框架结构</span><span>可以建起很高的建筑而花费的材料却很少，框架结构以</span><span style=" text-decoration: underline; ">三角形</span><span>为基本构造。</span><span></span><br><br><span>2</span><span>．框架铁塔结构特点：①</span><span style=" text-decoration: underline; ">上小下大</span><span>②</span><span style=" text-decoration: underline; ">上轻下重</span><span>③</span><span style=" text-decoration: underline; ">风阻小等。</span><span></span><br><br><span><strong>七、桥的形状和结构</strong></span><br><br><span>1</span><span>．桥面在拱下方的拱桥，桥板可以拉住</span><span style=" text-decoration: underline; ">拱足</span><span>，抵消拱</span><span style=" text-decoration: underline; ">向外</span><span>的推力，减少了桥墩的负担。桥面也比较</span><span style=" text-decoration: underline; ">低而且平坦</span><span>，方便通行。</span><span></span><br><br><span>2</span><span>．</span><span style=" text-decoration: underline; ">钢缆</span><span>能承受巨大的拉力，人们用它们建造的</span><span style=" text-decoration: underline; ">钢索桥</span><span>，大大增加了桥的</span><span style=" text-decoration: underline; ">跨越能力</span><span>。</span><span></span><br><br><span>3</span><span>．钢索桥的结构：由</span><span style=" text-decoration: underline; ">钢缆、桥塔、桥面</span><span>组成。</span><span style=" text-decoration: underline; ">钢缆</span><span>是桥承重的主要构件，</span><span style=" text-decoration: underline; ">桥塔</span><span>是支承钢缆的主要构件。桥塔修得高，是为了</span><span style=" text-decoration: underline; ">降低钢缆的拉力</span><span>。</span><span></span><br><br><span><strong>八、用纸造一座桥</strong></span><span></span><br><br><span>1．</span><span>用纸设计桥需考虑哪些问题：①纸这种材料的特性；②纸的承受力有什么特点；③选择形状和结构。④用什么方法增强纸的抗弯曲能力。</span><span></span><br><br><span>2</span><span>．</span><span style=" text-decoration: underline; ">杭州湾跨海大桥</span><span>全长</span><span style=" text-decoration: underline; ">36公里</span><span>，其长度在目前</span><span>世界上</span><span>在建和己建的</span><span>跨海大桥</span><span>中位居第一。于2008年5月1日正式通车。</span><span></span><br><br><span>3．评价一座桥好坏的指标</span><span style=" text-decoration: underline; ">：①是否坚固；②是否节省材料；③是否美观</span><span>。</span><span></span><br><br><br><div style="text-align: center;"><strong><font color="#38761d">第三单元 能量</font></strong></div><br><span><strong>一、电和磁</strong></span><span></span><br><br><span>1</span><span>．当导线中有电流通过时，导线的周围会产生</span><span style=" text-decoration: underline; ">磁性</span><span>。</span><span></span><br><br><span>2．1820年，丹麦科学家</span><span style=" text-decoration: underline; ">奥斯特</span><span>在一次实验中，发现通电的导线靠近指南针时，指南针发生了</span><span style=" text-decoration: underline; ">偏转。</span><span></span><br><br><span>3．如果电路短路，则电流很强，会很快把电池的电能用完，所以要尽快断开。</span><span></span><br><br><span>4．做通电线圈和指南针的实验时，</span><span style=" text-decoration: underline; ">线圈立着放，指南针尽量靠近线圈的中心</span><span>，指南针偏转的角度最大。</span><span></span><br><br><span><strong>二、电磁铁</strong></span><span></span><br><br><span>1．像这样由</span><span style=" text-decoration: underline; ">线圈</span><span>和</span><span style=" text-decoration: underline; ">铁芯</span><span>组成的装置叫</span><span style=" text-decoration: underline; ">电磁铁</span><span>。</span><span></span><br><br><span>2．电磁铁有</span><span style=" text-decoration: underline; ">南北极</span><span>。电磁铁的南北极与</span><span style=" text-decoration: underline; ">电池的接法</span><span>和</span><span style=" text-decoration: underline; ">线圈缠绕方向</span><span>有关，当电池正负极接法改变时，它的磁极也会改变；当电磁铁的线圈缠绕方向改变时，它的磁极也会改变。</span><span></span><br><br><span>3．</span><span>电磁铁与磁铁的相同点：</span><span style=" text-decoration: underline; ">都有磁性，都有南北极。</span><span></span><br><br><span>电磁铁与磁铁的不同点：（1）磁铁是磁性的石头，电磁铁是线圈和铁芯组成。（2）电磁铁只有通电才有磁性。（3）磁铁的南北极不会改变，而电磁铁的南北极可以改变。</span><span></span><br><br><strong><span>三、</span><span>电磁铁的磁力（一）</span></strong><span></span><br><br><span>1．电磁铁的磁力大小是可以改变的，磁力的大小与</span><span style=" text-decoration: underline; ">电池的数量</span><span>、</span><span style=" text-decoration: underline; ">线圈的圈数、铁芯的大小等有关</span><span>。</span><span></span><br><br><span>2．检验电磁铁磁力大小与</span><span style=" text-decoration: underline; ">线圈圈数</span><span>关系的研究计划表</span><div><span></span><br>
<table width="100%" border="1"><tbody><tr><td><br>研究的问题<br></td><td colspan="3"><br>电磁铁磁力大小与线圈圈数多少有关系吗？<br></td></tr><tr><td><br>我们的假设<br></td><td colspan="3"><br>线圈圈数多，磁力大；线圈圈数少，磁力小。<br></td></tr><tr><td><br>检验的因素（改变的条件）<br></td><td colspan="3"><br>线圈圈数<br></td></tr><tr><td><br>怎样改变这个条件<br></td><td><br>1．线圈20圈<br></td><td><br>2．线圈40圈<br></td><td><br>3．线圈60圈<br></td></tr><tr><td><br>实验要保持那些条件不变<br></td><td colspan="3"><br>电池的节数，电线的粗细，铁芯的大小等<br></td></tr><tr><td><br>实验结论<br></td><td colspan="3"><br>电磁铁磁力大小与线圈圈数多少有关系，线圈圈数多，磁力大；线圈圈数少，磁力小。<br></td></tr></tbody></table>
<br><strong><span>四、</span><span>电磁铁的磁力（二）</span></strong><span></span><br><br><span>1．检验电磁铁磁力大小与</span><span style=" text-decoration: underline; ">电池节数</span><span>关系的研究计划表</span></div><div><span></span><br>
<table width="100%" border="1"><tbody><tr><td><br>研究的问题<br></td><td colspan="3"><br>电磁铁磁力大小与电池节数多少有关系吗？<br></td></tr><tr><td><br>我们的假设<br></td><td colspan="3"><br>电池节数多，磁力大；电池节数少，磁力小。<br></td></tr><tr><td><br>检验的因素（改变的条件）<br></td><td colspan="3"><br>电池节数<br></td></tr><tr><td><br>怎样改变这个条件<br></td><td><br>1．电池1节<br></td><td><br>2．电池2节<br></td><td><br>3．电池3节<br></td></tr><tr><td><br>实验要保持那些条件不变<br></td><td colspan="3"><br>线圈圈数，电线的粗细，铁芯的大小等<br></td></tr><tr><td><br>实验结论<br></td><td colspan="3"><br>电磁铁磁力大小与电池节数多少有关系，电池节数多，磁力大；电池节数少，磁力小。<br></td></tr></tbody></table>
<br><span>2．</span><span>在进行科学探究中，探究的顺序：</span><span>1.</span><span>提出问题</span><span> 2.</span><span>建立假设</span><span> 3.</span><span>设计实验方案</span><span> 4.</span><span>收集事实与证据</span><span> 5.</span><span>检验假设</span><span> 6.</span><span>交流</span><span></span><br><br><span><strong>五、神奇的小电动机</strong></span><span></span><br><br><span>1</span><span>．换向器的作用是</span><span style=" text-decoration: underline; ">接通电流并转换电流的方</span><span>向，小电动机在转动的过程中，电刷依次接触换向器的三个金属环，通过转子线圈的电流方向就会自动改变。</span><span></span><br><br><span>2．小电动机包括</span><span style=" text-decoration: underline; ">外壳、转子、后盖</span><span>三部分。外壳内有一对永久磁铁，转子上有铁芯、线圈、换向器，后盖上有电刷。</span><span></span><br><br><span>3．电动机是</span><span style=" text-decoration: underline; ">用电产生动力</span><span>的机器。虽然大小悬殊、构造各异，但电动机工作的基本原理相同：</span><span style=" text-decoration: underline; ">用电产生磁，利用磁的相互作用转动</span><span>。</span><span></span><br><br><span><strong>六、电能和能量</strong></span><span></span><br><br><span>1．能量</span><span>有</span><span style=" text-decoration: underline; ">电能、热能、光能、声能</span><span>等不同的形式。运动的物体也有能量，叫</span><span style=" text-decoration: underline; ">动能</span><span>。能量还储存在燃料、食物和化学物质中，叫</span><span style=" text-decoration: underline; ">化学能</span><span></span><br><br><span>2．</span><span>任何物体工作都需要</span><span style=" text-decoration: underline; ">能量</span><span>。如果没有能量，自然界就不会有运动和变化，也不会有生命了。</span></div><div><span></span><br>
<table width="100%" border="1"><tbody><tr><td><br>输入的能量形式<br></td><td><br>用电器<br></td><td><br>输出的能量形式<br></td></tr><tr><td rowspan="5"><br>电 能<br></td><td><br>电饭锅<br></td><td><br>热能 <br></td></tr><tr><td><br>电风扇<br></td><td><br>动能<br></td></tr><tr><td><br>电视机<br></td><td><br>光能和声能<br></td></tr><tr><td><br>电 灯<br></td><td><br>光能<br></td></tr><tr><td><br>电 炉<br></td><td><br>热能<br></td></tr></tbody></table>
<br><span>3</span><span>．所有的用电器都是一个电能的</span><span style=" text-decoration: underline; ">转化器</span><span>，能够把输入的电能转化成其他形式的能。</span><span></span><br><br><span><strong>七、电能从哪里来</strong></span><span></span><br><br><span>1</span><span>．各种各样的电池：干电池（普通电池和钮扣电池）——</span><span style=" text-decoration: underline; ">化学能转化成电能</span><span>；太阳能电池——</span><span style=" text-decoration: underline; ">太阳能转化成电能</span><span>，不能储存电能，只能即时使用；蓄电池——放电时</span><span style=" text-decoration: underline; ">把化学能变成电能</span><span>，充电时把</span><span style=" text-decoration: underline; ">电能转化成化学能</span><span>。（用化学能的形式把电能储存起来）</span><span></span><br><br><span>2．当电动机被用来发电时，就应该叫</span><span style=" text-decoration: underline; ">发电机</span><span>。</span><span></span><br><br><span>3．电能的来源和转化</span></div><div><span></span><br>
<table width="100%" border="1"><tbody><tr><td><br>电能的来源<br></td><td><br>转化的能量<br></td><td><br>输出的能量形式<br></td></tr><tr><td><br>普通电池<br></td><td><br>化学能<br></td><td rowspan="5"><br>电能<br></td></tr><tr><td><br>光电池<br></td><td><br>光能<br></td></tr><tr><td><br>水电站<br></td><td><br>动能<br></td></tr><tr><td><br>热电厂<br></td><td><br>热能<br></td></tr><tr><td><br>核电站<br></td><td><br>核能<br></td></tr></tbody></table>
<br><span><strong>八、能量和太阳</strong></span><span></span><br><br><span>1．煤是由</span><span style=" text-decoration: underline; ">古代植物</span><span>变成的。古代植物死后，经过沉积作用，被泥沙覆盖，与空气隔绝，又经过地壳的变动，被埋到很深的地下，长期受到高温高压的作用，慢慢变成了煤。</span><span></span><br><br><span>2．石油、天然气是几亿年前大量的</span><span style=" text-decoration: underline; ">低等生物</span><span>经过长期复杂变化形成的。</span><span></span><br><br><span>3．煤、石油、天然气所具有的能量是存储了亿万年的</span><span style=" text-decoration: underline; ">太阳能</span><span></span><br><br><span>4．新能源：</span><span style=" text-decoration: underline; ">地热能、风能、潮汐能、核能、直接利用的太阳能</span><span>。</span><span></span><br><br><span>5．煤、石油、天然气是</span><span style=" text-decoration: underline; ">不可再生</span><span>的能源，用一点就少一点，我们正在耗尽这些能源。</span><span></span><br><br><span style=""><br clear="all" style="page-break-before:always"><div style="text-align: center;"><strong><font color="#38761d">六年级第四单元复习提纲</font></strong></div></span><br><span><strong>一、校园生物大搜索</strong></span><span></span><br><br><span>1．到目前为止，已经发现并分类记载的生物种类超过了</span><span style=" text-decoration: underline; ">200万种</span><span>，估计地球上现存的物种应有</span><span style=" text-decoration: underline; ">200万—450万种</span><span>。</span><span></span><br><br><span>2．科学家常常要对一个</span><span style=" text-decoration: underline; ">区域</span><span>的动植物种类和分布情况进行调查。</span><span style=" text-decoration: underline; ">分区域观察研究</span><span>是科学研究常用的方法。</span><span></span><br><br><span>3．调查校园中的动植物要注意：</span><span style=" text-decoration: underline; ">不要采摘植物和伤害动物；可以从脚印、粪便、毛等踪迹推知躲藏起来的动物，经常飞来的鸟也应该记下来；找生活在地下的小动物要带上小铲，最好带上放大镜；可以用绘画、拍照等适宜的方法记录不知名的动植物</span><span>等。</span><span></span><br><br><span><strong>二、校园生物分布图</strong></span><span></span><br><br><span>1．校园里的动植物</span><span style=" text-decoration: underline; ">种类</span><span>很多，生活的</span><span style=" text-decoration: underline; ">环境</span><span>也各不相同。</span><span></span><br><br><span>2．我国珍稀植物有</span><span style=" text-decoration: underline; ">珙桐</span><span> 、</span><span style=" text-decoration: underline; ">人参</span><span>、</span><span style=" text-decoration: underline; ">水杉</span><span>、</span><span style=" text-decoration: underline; ">银杏</span><span>、</span><span style=" text-decoration: underline; ">金花茶</span><span>等。</span><span></span><br><br><span>3．我国珍稀动物有</span><span style=" text-decoration: underline; ">大熊猫</span><span>、</span><span style=" text-decoration: underline; ">藏羚羊</span><span>、</span><span style=" text-decoration: underline; ">扬子鳄</span><span>、</span><span style=" text-decoration: underline; ">白鳍豚、亚洲象、金丝猴等</span><span>。</span><span></span><br><br><span><strong>三、多种多样的植物</strong></span><span></span><br><br><span>1．用</span><span style=" text-decoration: underline; ">分类的方法</span><span>可以帮助我们更好地辨别和研究动植物。</span><span></span><br><br><span>2．根据不同的标准可以将植物分成不同的类别。如根据茎的特点植物可以分为</span><span style=" text-decoration: underline; ">木本植物</span><span>（如：</span><span>桃树樟树）</span><span>和</span><span style=" text-decoration: underline; ">草本植物</span><span>（如：</span><span>狗尾草、水稻）</span><span>；根据生活环境将植物分为</span><span style=" text-decoration: underline; ">水生植物</span><span>（如：</span><span>浮萍）</span><span style=" text-decoration: underline; ">和陆生植物</span><span>（如：雪松</span><span>）</span><span>。</span><span></span><br><br><span>3．科学家主要是根据</span><span style=" text-decoration: underline; ">植物的特征</span><span>对植物进行分类。他们根据</span><span style=" text-decoration: underline; ">植物有没有花</span><span>把植物分成了两大类：</span><span style=" text-decoration: underline; ">开花的植物</span><span>和</span><span style=" text-decoration: underline; ">不开花的植物</span><span>。</span><span></span><br><br><span>4．在</span><span style=" text-decoration: underline; ">植物</span><span>王国中，已发现的种类有</span><span style=" text-decoration: underline; ">30多万种</span><span>，开花的植物约</span><span style=" text-decoration: underline; ">占一半以上</span><span>。</span><span></span><br><br><span>5．在不开花的植物中，</span><span style=" text-decoration: underline; ">蕨类、藻类、苔藓类</span><span>和</span><span style=" text-decoration: underline; ">开花的植物</span><span>一样，自己进行</span><span style=" text-decoration: underline; ">光合作用</span><span>制造养料。</span><span></span><br><br><span>6．不开花的植物包括</span><span style=" text-decoration: underline; ">蕨类</span><span>(如：蕨菜)、</span><span style=" text-decoration: underline; ">藻类</span><span>(如：紫菜)和</span><span style=" text-decoration: underline; ">苔藓类（</span><span>如：葫芦藓）植物等。</span><span></span><br><br><span>7．属于开花的植物有：桃树、油菜花、凤仙花、月季、金鱼藻等</span><span></span><br><strong><br><span>四、种类繁多的动物</span></strong><span></span><br><br><span>1．</span><span>科学家把动物分成</span><span style=" text-decoration: underline; ">脊椎动物</span><span>和</span><span style=" text-decoration: underline; ">无脊椎动物</span><span>两大类。</span><span>身体中</span><span style=" text-decoration: underline; ">有脊柱</span><span>的动物叫</span><span style=" text-decoration: underline; ">脊椎动物</span><span>，</span><span style=" text-decoration: underline; ">没有脊柱</span><span>的动物叫</span><span style=" text-decoration: underline; ">无脊椎动物</span><span>。</span><span></span><br><br><span>2．像蚂蚁、蝗虫、蜜蜂那样，身体上有</span><span style=" text-decoration: underline; ">三对足</span><span>的动物是</span><span style=" text-decoration: underline; ">昆虫类</span><span>；像金鱼、鲤鱼那样，终生在水中生活，用</span><span style=" text-decoration: underline; ">鳃</span><span>呼吸的动物是</span><span style=" text-decoration: underline; ">鱼类</span><span>；身体上长</span><span style=" text-decoration: underline; ">羽毛</span><span>的动物是</span><span style=" text-decoration: underline; ">鸟类</span><span>；直接</span><span style=" text-decoration: underline; ">生小动物</span><span>，并用</span><span style=" text-decoration: underline; ">乳汁</span><span>喂养小动物是</span><span style=" text-decoration: underline; ">哺乳动物</span><span>。</span><span style=" text-decoration: underline; ">爬行动物</span><span>：身体表面有鳞或甲，肚皮贴近地爬。</span><span style=" text-decoration: underline; ">两栖动物</span><span>：小时候在水里生活，用鳃呼吸；长大后在陆地生活，用肺呼吸。</span><span> </span><span></span><br><br><span>3．动物的</span><span style=" text-decoration: underline; ">身体构造和生命活动特征</span><span>是科学家对动物进行分类的重要标准。</span><span></span><br><br><span>4．在</span><span style=" text-decoration: underline; ">动物</span><span>王国中，已发现的种类已经有</span><span style=" text-decoration: underline; ">150多万种</span><span>，是生命世界中类别最多的。而</span><span style=" text-decoration: underline; ">昆虫</span><span>又是动物王国中种类</span><span style=" text-decoration: underline; ">最多</span><span>的，已知的昆虫达到100多万种，约占80%。</span><span></span><br><br><span>5．脊椎动物是动物身体中长有脊柱，构造比较复杂的一类，它又可以分为</span><span style=" text-decoration: underline; ">鱼类、两栖动物、</span><span> </span><span style=" text-decoration: underline; ">爬行动物、鸟类、哺乳动物。</span><span></span><br><br><span>脊椎动物： </span><span style=" text-decoration: underline; ">哺乳动物</span><span>：蝙蝠、羊、兔、猪、鲸、海豹</span><span><br></span><span> </span><span style=" text-decoration: underline; ">鸟 类</span><span>：鸡、鸭、鹅、老鹰、大雁、猫头鹰</span><span><br></span><span> </span><span style=" text-decoration: underline; ">爬行动物</span><span>：壁虎、蛇、鳄鱼、龟、蜥蜴、甲鱼</span><span><br></span><span> </span><span style=" text-decoration: underline; ">两栖动物</span><span>：蟾蜍、蝾螈、娃娃鱼</span><span><br></span><span> </span><span style=" text-decoration: underline; ">鱼 类</span><span>：海马、鲫鱼、鳗、泥鳅、黄鳝、鲤鱼</span><span></span><br><br><span><strong>五、相貌各异的我们</strong></span><span></span><br><br><span>1．不同的生物有</span><span style=" text-decoration: underline; ">各种不相同的特征</span><span>。</span><span></span><br><br><span>2．我们</span><span style=" text-decoration: underline; ">不能</span><span>找到</span><span style=" text-decoration: underline; ">两个相貌完全相同的人</span><span>。</span><span></span><br><br><span><strong>六、原来是相互关联的</strong></span><span></span><br><br><span>1．植物的叶具有进行</span><span style=" text-decoration: underline; ">光合作用</span><span>和</span><span style=" text-decoration: underline; ">蒸腾作用</span><span>的功能。仙人掌生活在缺水的沙漠，为了减少水分的蒸发，叶子退化成刺状，茎绿色、肥厚多汁，承担起</span><span style=" text-decoration: underline; ">光合作用和储存水分的功能</span><span>；松树生活的区域较为广泛，针形叶可以减少水分的蒸发，有利于保持身体温度；香蕉生活在水分充足的热带地区，叶子宽大，更有利于蒸发体内水分，调节植物体的温度。</span><span style=" text-decoration: underline; ">植物</span><span>所具有的</span><span style=" text-decoration: underline; ">不同的形态结构</span><span>是它们</span><span style=" text-decoration: underline; ">长期适应生活环境的结果</span><span>。</span><span></span><br><br><span>2．在不同环境中生活的</span><span style=" text-decoration: underline; ">动物</span><span>，也有明显</span><span style=" text-decoration: underline; ">不同的形态结构。</span><span></span><br><br><span>3．浮萍是水生植物中的</span><span style=" text-decoration: underline; ">浮水植物</span><span>，根系退化，</span><span style=" text-decoration: underline; ">只有一根较细的根</span><span>；小草和玉米都生活在陆地上，根既要</span><span style=" text-decoration: underline; ">将植物固定在土壤中</span><span>，又要负责从土壤中</span><span style=" text-decoration: underline; ">吸收水分</span><span>供植物体生活，因此它们都有庞大的根系。</span><span></span><br><br><span>4．生物的形态结构与它们所生活的环境和生活习性相关联。猫的脚</span><span style=" text-decoration: underline; ">有肉垫，在地上跑时发出的声音较小，不易被捕食对象发现</span><span>；</span><span style=" text-decoration: underline; ">带钩</span><span>的鸟爪，</span><span style=" text-decoration: underline; ">容易抓住树干，适宜生活在森林中，并有利于捕捉小动物</span><span>；鸭的脚</span><span style=" text-decoration: underline; ">有蹼</span><span>，</span><span style=" text-decoration: underline; ">可以用来划水，适宜生活在水中</span><span>；苍耳种子上</span><span style=" text-decoration: underline; ">有刺，在陆地上生活容易被动物携带传播</span><span>；莲子</span><span style=" text-decoration: underline; ">有较硬的外壳，可在水中漂流</span><span>；蒲公英种子上</span><span style=" text-decoration: underline; ">有毛</span><span>，</span><span style=" text-decoration: underline; ">容易随风飘移</span><span>。</span></div><div><span></span><br>
<table width="100%" border="1"><tbody><tr><td><br>动物名称<br></td><td><br>生活环境<br></td><td><br>身体特征<br></td><td><br>功能<br></td></tr><tr><td rowspan="3"><br>金鱼<br></td><td rowspan="3"><br>水中<br></td><td><br>鳃<br></td><td><br>水中呼吸<br></td></tr><tr><td><br>鳍<br></td><td><br>水中游泳<br></td></tr><tr><td><br>纺锤形<br></td><td><br>减少水对它的阻力<br></td></tr><tr><td rowspan="3"><br>鸽子<br></td><td rowspan="3"><br>空中<br></td><td><br>羽毛<br></td><td><br>保温，防水<br></td></tr><tr><td><br>骨骼中空<br></td><td><br>身体轻，便于飞行<br></td></tr><tr><td><br>长有翅膀<br></td><td><br>空中飞行<br></td></tr></tbody></table>
<br><span><strong>七、谁选择了它们</strong></span><span></span><br><br><span>1．在田野中，绿色青蛙因为有好的伪装而被保留下来，其它颜色的青蛙因为过于显眼而被猎食者吃掉。</span><span></span><br><br><span>2．生物学家对不同地方的生物个体进行比较时，发现了一个非常有趣的现象，即同一种生物，</span><span style=" text-decoration: underline; ">愈冷</span><span>的地方，个体就</span><span style=" text-decoration: underline; ">愈大</span><span>，身体愈接近</span><span style=" text-decoration: underline; ">圆形</span><span>；并且鼻子、耳朵、腿等暴露在外部的器官就</span><span style=" text-decoration: underline; ">越小</span><span>。</span><span></span><br><br><span>3．环境发生改变，动物的</span><span style=" text-decoration: underline; ">形态结构</span><span>也相应发生变化。多样的生物是由多样的环境造成的。</span><span></span><br><br><span>4．</span><span style=" text-decoration: underline; ">大自然的选择</span><span>使得生物发生变化，然而</span><span style=" text-decoration: underline; ">人工选择</span><span>也在丰富着物种的多样性。</span><span></span><br><br><span>5．在实验中，我们发现</span><span style=" text-decoration: underline; ">大的球形烧瓶这个容器内的水温降得慢，细而长的玻璃瓶这个容器内的水温降得快</span><span>。在大自然中，大而圆的动物的体形降温慢。</span><span></span><br><br><span><strong>八、生物多样性的意义</strong></span><span></span><br><br><span>1．地球是我们美丽的家园，</span><span style=" text-decoration: underline; ">各种各样的生物</span><span>，在这个家园中都扮演着不同的角色，它们</span><span style=" text-decoration: underline; ">相互依存，相互作用，相互影响</span><span>着。</span><span></span><br><br><span>2．</span><span style=" text-decoration: underline; ">生物的多样性</span><span>是人类生存与发展的基础。</span><span><br></span><span>3．每种生物都与人类</span><span style=" text-decoration: underline; ">生活</span><span>息息相关。人类的衣食住行离不开生物的多样性。</span><span></span><br><br><span>4．多样的生物对我们人类有不同的</span><span style=" text-decoration: underline; ">价值</span><span>。有的具有欣赏价值和科学价值，有的具有经济价值，有的具有药用价值。</span><span></span><br><br><span>5．就像人类生活离不开生物的多样性一样，每一种生物也需要生活在</span><span style=" text-decoration: underline; ">生物多样性</span><span>的环境之中。举例：</span><span style=" text-decoration: underline; ">花繁殖后代需要昆虫帮助传粉；苍耳靠动物传播种子；动物排出的粪便可成为植物的养料；蝗虫生活需要以水稻等植物为食物。</span><span></span><br><br><span>6．保护生物多样性，要从保护</span><span style=" text-decoration: underline; ">家乡</span><span>生物多样性做起。</span><span></span><br><br><span>7．人类是生物大家族中的一员，我们理应</span><span style=" text-decoration: underline; ">平等</span><span>对待家族中的每一个成员。</span><span></span><br><br><span>8．人类生活离不开</span><span style=" text-decoration: underline; ">植物</span><span>：提供给人类做食物；供人类欣赏；提供给人类做药材；人类可以用植物做成生活及学习用品；可以净化空气；提供给动物做食物。</span><span></span><br><br><span><strong>资料库：</strong></span><span></span><br><br><span>1．生物的基本生存条件包括</span><span style=" text-decoration: underline; ">阳光、空气、水源和地域</span><span>等。</span><span></span><br><br><span>2.《生物多样性条约》于</span><span style=" text-decoration: underline; ">1993年</span><span>正式开始实行。</span><span></span><br><br><span>3．每年的</span><span style=" text-decoration: underline; ">5月22日</span><span>被称为国际生物多样性日。</span><span></span><br><br><span>4．全世界已有</span><span style=" text-decoration: underline; ">180</span><span>多个国家成为《生物多样性条约》缔约国。</span><span></span><br></div><div><span><br></span></div>
六年级上