<p class="ql-block"><b>2B Unint 9 I can hear-2</b></p><p class="ql-block">视频:清华英语，复述粉猪第一季</p><p class="ql-block">音频:清华英语，汉语第三册</p> <p class="ql-block"><b>Mini phone</b></p><p class="ql-block">M: We will make two paper cup phones. Take a paper cup. Use a pencil tip to poke a small hole at the bottom.</p><p class="ql-block">M: Next, thread the string through the hole of the cup. Tie a knot in the yarn on the inside of the cup to keep it in place. Ok, now thread this end of the string through the hole of your cup. Tie a knot.</p><p class="ql-block">M: Now, we can use our paper cup phones to talk. Stretch the string. Keep the string taut. Put the phone against your ear.</p><p class="ql-block"><b>Tips:</b></p><p class="ql-block">原理Why does it work?</p><p class="ql-block">Sound waves can travel through air, solids, and liquids.</p><p class="ql-block"><br></p><p class="ql-block">Because the cup and string are solid, and solids actually carry sound waves better than air, the whisper can be heard much clearer than if you were to just whisper into the air from that distance.</p> <p class="ql-block"><b>Make Music with Water Glasses</b></p><p class="ql-block">（来自1807Samy妈妈）</p><p class="ql-block">In this science experiment, we explore sound and pitch（音高） by turning glasses of water into musical instruments.</p><p class="ql-block"><b>we need:</b></p><p class="ql-block">Water glassed all the same size.</p><p class="ql-block">a measuring cup</p><p class="ql-block">a pencil</p><p class="ql-block">1.Pour one ounce of water into the first glass,two ounces into the second glass,three ounces into the third glass,and so on ...</p><p class="ql-block">2.Tap each glass with pencil</p><p class="ql-block">3.listen to the sound that comes from each galss,the less water in the glass,the higer the sound will be.</p><p class="ql-block">4.Tap on each glass,go on the scale,Godown the scale,pretend you are playing a tune on a xylophone.</p><p class="ql-block"><br></p><p class="ql-block">Sound waves themselves are invisible,</p><p class="ql-block">but you can sometimes feel them, and</p><p class="ql-block">you can see them when they bump into something solid and make it move.</p><p class="ql-block"><br></p><p class="ql-block">The sound waves sound the same when the glasses are empty, but when youadd water, it changes the size of the sound waves, because many of the sound waves created have to travel through the water before they can reach your ear.</p><p class="ql-block">This changes the pitch of the sound you are hearing.</p><p class="ql-block">The more water, the lower the pitch. The less water, the higher the pitch.</p> <p class="ql-block"><b>Sound And Volume声量 Vibrations</b></p><p class="ql-block">（来自1807Samy妈妈）</p><p class="ql-block">This science experiment is a great way</p><p class="ql-block">to help you understand sound and volume vibrations. Have fun experimenting with different noises and music to see how the grains of salt bounces.</p><p class="ql-block">这个科学实验是帮助你理解声音和音量振动的好方法。尝试不同的声音和音乐，看看盐巴是如何弹起来的。</p><p class="ql-block"><b>Materials:</b></p><p class="ql-block">Radio or CD Player with music</p><p class="ql-block">Large glass bowl</p><p class="ql-block">Plastic wrap包装</p><p class="ql-block">Rubber Band橡皮筋</p><p class="ql-block">grains of salt</p><p class="ql-block"><br></p><p class="ql-block">This is also a very loud experiment, Use your ear protection because of your sensitivity to sound. You can keep this set of ear protective ear muffs on hand for various</p><p class="ql-block"><b>Directions:</b></p><p class="ql-block">1. Place a piece of plastic wrap on the top of a glass bowl and straighten as best as possible. Wrap a rubber band around the plastic wrap to hold it in place.</p><p class="ql-block">2. Set grains of salt onto the plastic wrap. </p><p class="ql-block">3. Place the bowl next to a speaker and play music. Is the salt moving?</p><p class="ql-block"><b>Turn up the volume: Now what happens?</b></p><p class="ql-block">Try another type of music: What level of volume makes the grains of salt move?</p><p class="ql-block">Sound vibrates air. The sound from thespeakers makes the air vibrate which makes the salt on the bowl vibrate. This makes the grains of salt bounce around.</p><p class="ql-block"><br></p><p class="ql-block">使用方法:</p><p class="ql-block">1. 在玻璃碗的顶部放一块保鲜膜，并尽可能地拉直。用橡皮筋把塑料膜固定住。</p><p class="ql-block">2. 将一些盐巴放在保鲜膜上。</p><p class="ql-block">3.把碗放在扬声器旁边，播放音乐。盐巴在动吗?</p><p class="ql-block">提高音量:现在发生了什么?</p><p class="ql-block">试试另一种音乐:什么样的音量能让盐巴动起来?</p><p class="ql-block">声音振动的空气。扬声器发出的声音使空气震动，使碗上的塑料薄膜震动。这使得盐巴在周围弹跳。</p><p class="ql-block"><br></p><p class="ql-block">月球表面几乎听不到声音，因为月球上传播声音的空气极其稀薄，几乎不能传递声音。</p> <p class="ql-block">自己做的盐巴实验不是很明显，找了一个视频来展示，更加直观！</p> <p class="ql-block"><b>指读</b></p> <p class="ql-block">跟她说好多人看她玩游戏和指读，今天读书特别来劲，表现很棒！</p>