“2-1我们怎样听见声音”演示课件1.ppt

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. 一．声音是怎样产生的？ 请大家思考一下，在我们教室里可以做什么活动发出声音？ 敲桌子 拨动尺子 唱歌、说话 敲击音叉 拍手 动手试试看！ 抖动纸 将手指按住自己的 喉头两侧后说话… 等 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. 实验证明，声音是由于物体振动产生的。 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. 敲击音叉时，谁看见音叉在振动？ 谁用可见的实验来证明？ 转换思想 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. 一切发声的物体都在振动，振动停止，发声也停止 思考：用手握住正在发声的音叉，又会怎样？ 振动停止，发声停止，但声音并不消失 （声音向远处传播） 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. 固体、液体、气体都能因振动而发声吗？（举例说明） 风声雨声读书声－－－－ 空气　雨　声带 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. 生活中的疑问 我们平常听唱片、录音是怎么回事？ 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. 二、声音是怎样传播的 以音叉为例：音叉振动时，会压缩左侧和右侧的空气，左右侧空气疏密相间，随着音叉的不断振动，空气中就形成了疏密相间的波动向远处传播