Sound & Frequency (SOL 5.2)

Sound and Frequency

Topic:

Concept:

SOL:    5.2

The student will investigate and understand how sound is transmitted and is used as a means of communication. Key concepts include

• frequency, waves, wavelength, resonance, vibration;
• the ability of different media (solids, liquids, gases) to transmit sound; and
• communication tools (voice, Morse code, sonar, animal sounds, musical instruments).

Rationale:

Goals:

Objective:The student will be able to change the pitch of a water-filled glass by pouring water out of or into a glass with 100% accuracy.

The student will be able to orally state why the pitch changes with 75% accuracy.

The child will describe a theory that might explain why stethoscopes amplify sound.

The child will identify the cochlea inside the model of the ear with 100% accuracy and draw a model of how hearing occurs.  The model will list at least three stages that occur before people have heard a sound.

The child will predict his or her own speech frequency with 70% accuracy.

Content:

Sound waves

Sound through solids

Pitch

Frequency

Hypothesis building

Affective:

The children will work cooperatively in groups and share materials graciously.

Psychomotor:

The children will manipulate many objects, exercising their fine motor skills.  Also, the children will exercise controlling their vocal cords by attempting different pitches.

Materials:

Station 1:

5 glass bottles

5 chalkboards

water

spoon

Station 2:

5 stethoscopes

white board

white board markers

Station 3:

model of ear with cochlea and ear drum

construction paper

markers

book about the human ear (Eyewitness Books)

Station 4:

microphone

laptop with sound frequency display

paper

Station 5:

Wooden plank

Bowl

salt

Sarah wrap

Percussion instrument

Procedure:

Navajo Code Breakers

Introduce the book and talk about Morse code.  Show the children pictures of soldiers in the book using sound to win World War II.  Why would people speaking an American Indian language over radio transmissions be so important?

Station 1:

Change the pitch.  Fill the different glass jars with different amounts of water.  Tap the glasses lightly with a spoon. Which jars ring with the highest pitch?  Draw the frequency for each glass on the chalkboard in front of it.

Station 2:

5 stethoscopes

Try the stethoscopes on and listen to your heartbeat.

Together, write on the white board different theories that can explain why stethoscopes work.

Notice that the tube is very thick rubber, almost solid.  Why wouldn’t it be thin and full of air?  Leave room for other groups to list their theories, too.

Station 3:

As you refer to the model and the diagram of the ear on page 6 of the book at your station, make your own ear diagram on construction paper.

Can you identify the cochlea in the ear model?  Compare your answer with a partner’s answer.  Can you use the book as a reference to find which part on the model is the cochlea?

Station 4:

The child will be blindfolded.  His or her friends will control the computer as it records the sound the blindfolded child makes.  The friends will hide the frequency display.  The child will draw what he or she thinks the frequency should look like.  The children will compare the two and, if the prediction is not accurate, determine why and explain it to each other.

Station 5:

Put your ear on the end of the wooden shelf.  Ask a partner to scratch the opposite end very lightly.  Do you hear the sound better through the solid or through the air?

Create the eardrum model we saw on Bill Nye.  Use tape to secure the bag over the bowl.  Tap until you see the salt jump and the bag vibrate.  Tell your partners what you think is happening.

Closure:

Proceed through each station and talk about the results.  Ask children to help clean up.  Dismiss class.