《我们怎样听见声音杭州下城朝晖附近中考物理暑假辅导班新王牌教育2.ppt

我们生活的世界充满了各种声音 杭州下城朝晖附近中考物理暑假辅导班 新王牌教育 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 探究 一、声音是怎样产生的？ 将手指按住自己的喉头两侧后说话 尺子的发声 用手抖动纸 扁担发声 鼓发声a 鼓发声b 音叉发声a 音叉发声b 我们怎样听见声音 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 1.声音是由物体的振动产生的 声源：正在发声的物体 思考：按住正在发声的鼓又会怎样？ 2.振动停止，发声(声音的产生)也停止 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 声音产生的条件: 声音由物体的振动产生,振动停止,声音的产生也停止 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 探究 二、声音是怎样传播的（声音的传播形式） Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 音叉发声 声音以声波(声波象水波一样，从声源处象四周传播。)的形式传播。 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 1．回声—声音在传播的过程中，如遇到障碍物就会被反射回来，反射回来的声音叫做回声 三、 2．人耳能分清前后两次声音的时间间隔应大于1/15 s Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 四、声音传播需什么条件？ 铃实验 声音传播需气体、液体、固体等介 质，真空不能传声.且声音在固体在传播的效果最好. Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 五、声音传播的快慢 １、声速：单位时间内，声音传播的距离。 ２、声速的大小与介质的种类、温度有关。 a 、Ｖ固V液V气 b、V空 =340 m/s Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 六、人耳是怎样听见声音的？ 发声体振动发声→声音以声波的形式在介质中传播→引起鼓膜振动→听觉神经 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.