Cambridge Secondary (7-9). Stage 9. MCE Science. Student Book - Unit 11: Sound

Close your eyes and listen carefully. What do you hear? Do you hear sounds that are soft, loud or high-pitched? Maybe you hear the loud sound of a car or another machine running. Maybe you hear a soft, high-pitched sound of a bird singing in a tree.

Open your eyes and share the sounds you heard with the rest of the class. Where do these sounds come from? How are they formed? Was it easy to describe the sounds to your classmates?

How do you think an understanding of sound can help the environment?

Create a list of careers that work with sound or rely on sound.

In groups, discuss your suggestions.

1 Work in groups. Stretch out a slinky (a spring toy) loosely on a horizontal surface. Fix or hold one end of the slinky steady (Figure 11.7, top).
2 Quickly compress and release a few coils at the other end. This will create a wave that travels along the length of the slinky (Figure 11.7, bottom).
3 How does this experiment show how a sound wave moves?

Share your answers with the class.

The human voice is produced by air passing from the lungs through the vocal cords (Figure 11.6). The vocal cords vibrate and produce sound.

Why does voice differ from person to person?

Discuss this in your group.

The human voice is produced by air passing from the lungs through the vocal cords (Figure 11.6). The vocal cords vibrate and produce sound.

Do you think that any two people could have exactly the same voice?

Discuss this in your group.

In groups, demonstrate sound vibrations. Work on a solid surface like a wooden block or a tabletop. Ask your teacher for a rubber pad, a tuning fork and a bowl with water.

Strike the tuning fork against the rubber pad. Place the fork's prongs just above the surface of the water (Figure 11.9). What do you observe? Why does this occur?

Discuss in groups and share your findings with the class. You may use the Internet or other sources of information to help you.

In groups, demonstrate sound vibrations. Work on a solid surface like a wooden block or a tabletop. Ask your teacher for a rubber pad, a tuning fork and a bowl with water.

Watch how the vibrating tuning fork causes ripples in the water (Figure 11.10). What do the ripples represent?

Discuss in groups and share your findings with the class. You may use the Internet or other sources of information to help you.

In groups, demonstrate sound vibrations. Work on a solid surface like a wooden block or a tabletop. Ask your teacher for a rubber pad, a tuning fork and a bowl with water.

Repeat the experiment with the tuning fork in different positions. Hold it closer to or further from the water's surface, or next to the bowl. Record your observations.

Discuss in groups and share your findings with the class. You may use the Internet or other sources of information to help you.

In groups, demonstrate sound vibrations. Work on a solid surface like a wooden block or a tabletop. Ask your teacher for a rubber pad, a tuning fork and a bowl with water.

If this experiment took place in a vacuum where there are no air particles, what would happen? Would the water show ripples when the tuning fork is placed above its surface? Explain your answer.

Discuss in groups and share your findings with the class. You may use the Internet or other sources of information to help you.

In groups, demonstrate sound vibrations. Work on a solid surface like a wooden block or a tabletop. Ask your teacher for a rubber pad, a tuning fork and a bowl with water.

Why was the tuning fork held above the water instead of being placed in the water?

Discuss in groups and share your findings with the class. You may use the Internet or other sources of information to help you.

In groups, demonstrate sound vibrations. Work on a solid surface like a wooden block or a tabletop. Ask your teacher for a rubber pad, a tuning fork and a bowl with water.

Discuss what you could do to improve the experiment.

Discuss in groups and share your findings with the class. You may use the Internet or other sources of information to help you.

Why does sound need a medium such as air or water to travel in?

How is sound produced? Give an example.

In what form does sound travel?

In a sound wave, what do we call the region where air particles are pulled further apart?

Waleed works in a factory. There is a lot of noisy machinery running the whole day.

In groups, answer the following questions. You can use the Internet or other sources of information.

What can Waleed do to protect his ears and hearing when he is at work?

Share your answers with the class.

Waleed works in a factory. There is a lot of noisy machinery running the whole day.

In groups, answer the following questions. You can use the Internet or other sources of information.

What can the factory managers do to reduce the noise levels?

Share your answers with the class.

Waleed works in a factory. There is a lot of noisy machinery running the whole day.

In groups, answer the following questions. You can use the Internet or other sources of information.

Why is it important to control noise levels?

Share your answers with the class.