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Lesson Plan Ideas - Sound Connexions  Science and Technology Self and Society
Language
Resources -Vocabulary-Related BooksThe Arts MathThe Telephone
Obtain and disassemble an expendable telephone. Encourage students to examine the jack, the electronics box, bell, dial and handset. Discuss how the various components work. (See Can We Help You?) An electromagnet is found in the ear-piece of a telephone. Demonstrate an electromagnet with a nail, wire coil and batteries. Show how the nail magnetizes and de-magnetizes as the electric current is turned on and off. In the telephone ear-piece, the electrical current does not switch on or off, but fluctuates as it travels along the wire. This current, in turn, reflects the amount of electromagnetism produced, and vibrates the diaphragm in the ear-piece. Sound Vibrations Have students press their fingers to their Adam's Apples and make sounds. They should feel the vibrations of their vocal cords. Demonstrate how a vibrating ruler creates sounds also. Inside the larynx are two bands of strong tissue, the vocal cords. The outer edges are attached to the larynx, leaving the inner edges free to move. The muscles of the larynx tighten or loosen the cords. When air is forced past them, they vibrate, producing sound. The sounds we make are also controlled by our lips, the shape of our mouth, our tongue, our teeth and our nasal cavity. Demonstration #2 - To show that a tuning fork produces sound vibrations.
Take a large tuning fork and hit it with a rubber hammer. Ask the students if they can see the tuning fork vibrate. Can they hear the tuning fork? Hit the tuning fork again. Put it in the resonance box or touch it on the table to demonstrate that, in fact, the tuning fork is making a sound. Hit it again and touch the surface of water in a bowl with the tip of the tuning fork. Watch what happens. Repeat this demonstration on the overhead projector so that the water can be clearly seen to splash with the vibrations. Have one or two students repeat this demonstration. Demonstration #3 - To show that sound waves vibrate air.
Shine the flashlight onto the end of the drum so that the light reflects from the drum surface to the wall or ceiling. Shout into the open end of the drum. What happens? The sounds vibrate the air in the drum, which in turn vibrates the reflective materials. The patterns of light will vibrate the way the air vibrates inside the tin. The higher the pitch of the sound, the faster the light vibrates. Demonstration #4 - To show that waves move away from their source.
Place a shallow glass bowl of water on the overhead projector and project the image on the screen. Using the dropper, slowly drop water into the middle of the bowl. Circular waves move away from the point of impact and can be clearly seen. Similarly, sound waves move away from where a sound is produced so that we can hear it. We pretend that the drop of water from the dropper is the source of the sound.
Frequency Demonstration #1 - To show that the size of an object affects the pitch of a sound.
Show the students the tuning forks and note which is larger. Discuss the fact that larger objects move more slowly than smaller objects if given the same push. Take one fork and hit it with the rubber mallet. Put it in the resonance box or on the table so that you can hear the sound. Do the same with the other tuning fork. Discuss which tuning fork produces the higher/lower sound. Relate the size of the tuning fork to the pitch of the sound. Demonstration #2 - To show that the size of an object affects the pitch of a sound.
Discuss the size of the strings before you pluck them. Have the students guess which will make the higher sound and which will make the lower sound. Demonstration #3 - To show that the slower the vibration, the lower the sound.
With the wooden mallet, tap the glass with no water in it. Ask a student to add a little water and tap the glass again. Discuss the difference in sound. Add more water and have the students predict what will happen to the sound. Continue to do this until the concept is clear. The more water in the glass, the less the glass can vibrate and the lower the sound. If you would like the students to try this, see the activity sheet. Demonstration #4 - To show that the distance between waves is related to the rate of vibrations at the source.
Place a dish of water on the overhead projector. Drop water from the dropper slowly into the dish. Draw attention to the distance between the dark circles. Pretend that the dark circles are like the sound waves (that we cannot see) travelling through the air. Now drop the water from the dropper more quickly. Draw attention to the distance between the dark circles. How is the distance different than before? (The circles are closer together.) If a source of sound is vibrating slowly, then the sound waves will be far apart. If it is vibrating more quickly, then the waves are closer together. This demonstration works best if you use the dropper as close to one edge of the container as possible. The waves are more clearly defined, even though you do not see a complete circle.
Demonstration #1 - To show that the more we push an object to vibrate, the louder the sound. Explain that if we yell loudly, we squeeze the air particles more than if we whisper. The more that we push an object to make it vibrate, the larger the vibrations and the louder the sound, or the greater the amplitude. Sound waves with the same frequency can be very different in volume. Demonstration #2 - To show that the more we push an object to vibrate, the louder the sound.
Ask a student to hit the same note of the xylophone with varying amounts of force. Explain that the pitch of the sound does not change, but that what has changed is the volume. The more energy we use, the louder the sound. Demonstration #3 - To show that the size of a wave is related to the degree of push at its source.
Drop the water from the dropper close to the water surface and observe the size of the wave. Raise the dropper high above the dish and allow the water to drop at the same rate. Notice the size of the wave. How are the waves different? (They are different in size or amplitude.) Why? (When the dropper is high, there is more push or energy in the drop when it hits the water than when it is low.) Divide the class into groups of five students. With each group, build a local telephone network by connecting each student with a string to a desk in the middle of the group. Make a diagram of the networks, using a telephone to represent each student, and put the student's name next to the telephone. Connect the desks together using string. Make sure that each node is connected to every other desk. Trace the path of a call from a student at one end of the class to a student at the other end. If you are calling someone else in your local exchange, how is your phone connected to theirs? If you call someone outside the exchange, how are you connected? Telephone Number
Write down your telephone number and identify the three parts of the number representing your area, your exchange and your phone. Use the telephone book to find other area codes. Discuss the purpose of the different parts of a telephone number. The first three digits are the area code. They represent an area of the country around the city in which you live. The next two digits represent a group of up to 100,000 telephones linked together in what is called an exchange. There are several exchanges in each area. The last five digits identify a specific telephone in the telephone exchange. Communication Have students think about how we send messages (communicate). Explore different ways of sending messages over long distances (using flags, light, sound). Have them create code messages to send to each other. Challenge students to send a secret message to a student in another room. Sounds To introduce the concept of sound to your class, ask the students to write down every noise (loud and soft) that they hear for a period of 3 to 5 minutes, as well as the source of the sound. Have the students write a poem "Sound is ...". Music Make a musical instrument.
Have groups of students research and create their own musical instruments flute, shakers, percussion, strings (elastic bands), etc. Students may wish to explore the making of instruments with household objects - spoons, cookie sheet, bowls, tumblers etc. Have the students think about the pitch and amplitude produced by their instruments. How can they be ? Try an orchestrated arrangement with two or three students working together on their instruments to produce music. The speed of sound in dry air at 0§C is 331.6 m/sec. If it takes 10 seconds for a sound to reach your ears, how far away was its source? (331.6m X 10 = 3316 metres) Can you estimate the distance of a thunderstorm by measuring the time between a flash of lightning and the sound of thunder? The speed of sound in water at ordinary temperatures is 1525 m/sec. If it takes 10 seconds for a sound underwater to reach your ears, how far away was its source? (1525m X 10 = 15250 metres) The speed of sound through steel is 4877 m/sec. If it takes 10 seconds for a sound to reach your ears through steel, how far away was its source? (4877m X 10 = 48770 metres) Ask the students what they can conclude about sound as it travels through different substances. Questions about school programs should be sent to scorbeil@technomuses.ca. |
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