Lesson: City Gone Silent

Compare quiet and loud sounds.

• As a class, brainstorm different sounds you encounter every day and try to classify each as “loud” or “quiet.” Ask: Which sounds did everyone agree were loud or quiet? Which were difficult to classify? Ask students for their ideas on how sound travels from a source to their ears. Let students sketch out their initial ideas.

Model sound vibrations. Find step-by-step instructions in our bonus Slide Deck “Seeing Sound Waves.”

• Tightly stretch plastic cling wrap over a large glass or metal bowl and sprinkle rice or salt on top. Hold a metal pot near the bowl and hit the pot firmly with a metal spoon. (Note: You can invite students to watch from a safe distance, or you can project the demonstration.) Ask: What happens to the rice? (It moves.) 
• Play the video “Sounding Off.” Then hit the pot again and ask students what is happening. Work together to illustrate the explanation on the board. (The tapping vibrates the pot. The vibrating pot vibrates the air. That vibration travels through the air. When it reaches the bowl, the plastic wrap vibrates, moving the rice. Explain that this is also how sound travels to people’s ears.)
• Ask students to predict what would happen if you were to hit the metal harder. (Louder banging will cause larger vibrations, moving the rice or salt more.) Test their predictions. 
• Tell students that sound also vibrates their eardrums, which are stretched tightly, just like the plastic wrap. Ask students whether this model helps explain why loud sounds can hurt your ears. (Yes, because it shows how the bigger vibrations from loud sounds hit your eardrums harder, causing them to vibrate more.)

Read an article about the causes and effects of noise pollution.

• Preview the article and the “Words to Know” on page 6. Read the article as a class. 
• Have students sit silently for a full minute and then note any sounds they heard. Ask: How did the sounds affect you? Did you hear sounds that could be noise pollution? Discuss. Then have students complete the Quick Quiz.

Complete a map skills sheet about noise pollution.

• Preview the map skills sheet Noisy Nation. Have students complete it in pairs and discuss answers as a class. 
• Invite students to complete the Learning Extension (found below and at the end of the scrollable article online) about sounds in their neighborhood.

Check for understanding with a paired text about noise pollution in the oceans.

• Distribute the Land Sounds vs. Sea Sounds skills sheet. Read the passage aloud and preview the questions. Allow students to work in pairs and then discuss answers as a class.

⇨ Learning Extension: What sounds do you hear in your neighborhood? Write down what you hear at different times for a week. Discuss your results with a family member. Do you think there’s noise pollution in your neighborhood?