2 days (max)

Day 1

Day 2

Good VibrationsMonday March 26th , 2012

Warm-up: (1) Draw a tuning fork on your paper.(2) Using prior knowledge, describe what a tuning fork does.

Objective: Students will be able to analyze the behavior of sound waves in order to explain how sound waves transfer energy.

Homework:

Good VibrationsINBOXFromDate: Today

We have been learning a lot about waves in general. I’m interested in the sound job. Do you think what we learned about waves and energy applies to sound?

It would be logical but sometimes the logical isn’t always correct.

I think I should check into this to be safe. Maybe I can conduct some investigations to see. Gotta split! I have a lot to research.

Activity A: Observing Energy TransferThe world is full of many different sounds. The

roar of a jetliner, the crash of a ball through a window, the voice of a singer; these and other sounds result from energy transfers. In this investigation, you will observe energy transfers which produce sound.

FIGURE 1

Tines Handle

Hold the tuning fork in one hand. Strike the tuning fork with the mallet. See Figure 1.

1. Describe your observations of the tuning fork tines after being struck by the mallet.

2. Strike the tuning fork. Touch the tines to the

surface of the water in the beaker. What evidence is there that energy from the

tuning fork was transferred to the water?

The water splashed around at the The water splashed around at the surface of the beaker. This shows that the surface of the beaker. This shows that the energy transferred from the tuning fork to the energy transferred from the tuning fork to the water.water.

Review/ Discussion

Identify the source of energy that caused the vibrations on the tuning fork.

Striking the tuning fork (creating a Striking the tuning fork (creating a disturbance) transferred the energy into the disturbance) transferred the energy into the tuning fork.tuning fork.

We call the motion of the tuning fork tines vibration. A vibration is a rapid back-and-forth repeating motion.

3. Complete the sequence chain to show the energy transfers in procedure 2.

Striking the

tuning fork

Tuning Fork

Water

4. Strike the tuning fork. Place the tuning fork Strike the tuning fork. Place the tuning fork near, but not touching, your ear. near, but not touching, your ear.

Identify evidence that energy in the tuning fork is transferred to the air.

5. Strike the tuning fork against the desk. Pick up a piece of paper and touch the tines to the paper.

Identify evidence that energy in the tuning fork is transferred to the paper.

6. Strike the tuning fork. Place the bottom of the tuning fork on the table top.

Identify evidence that energy in the tuning fork is transferred to the table.

Analysis #1

The strings of the banjo make sounds that are similar to the tone produced by the tuning fork. Construct a sequence chain to show the energy transfers that occur when the banjo is played and you hear the sound.

Good VibrationsTuesday March 27th , 2012

Warm-up: (1) Identify 2 pieces of evidence that a tuning fork has energy in it after striking a table.

Objective: Students will be able to analyze the behavior of sound waves in order to explain how sound waves transfer energy.

Homework: Wave Interactions HW #2

Classwork

You have observed evidence of energy transfer in sound waves. How exactly are sound waves produced? How is energy transferred in a sound wave? In order to answer these questions, you will need to do a little research.

Read the passage “The Nature of Sound” on pages 36-37 of the Prentice Hall: Science Explorer, Sound and Light.

1. Explain how sounds are produced. Justify your answer using information from the text.

2. Explain how energy is transferred in a sound wave. Justify your response using information from the reading.

1. Explain how sounds are produced. Justify your answer using information from the text.

Sounds are made when the medium is vibrating.

For example, a drum creates a disturbance which pushes the molecules of the air near it and creates sound.

2. Explain how energy is transferred in a sound wave. Justify your response using information from the reading.

Energy is transferred in a sound wave by the creation of compressions and rarefactions, which will cause the molecules of the medium to hit other molecules.

This passes the energy along.

Vocabulary ReferenceCompressions

When the particles of a medium are close together

RarefactionsWhen the particles of a medium are far apart

Exit TicketAn opera singer is practicing for a

performance. When she hits a high note, the glass of water on the table shakes. Explain why the glass shakes. Justify your answer using what you have learned about energy transfer.

DemonstrationObserve the demonstration.

Determine how energy is related to loudness of a sound.

As the energy put into making the sound __________,

the loudness of the sound _________________.

PredictionPredict what you think will happen to the

loudness of the sound provided by the ruler as we increase the amplitude.

As we increase the amplitude of the ruler I think the loudness will…..

InvestigationObserve the loudness of the ruler for each

amplitude.

Determine if the loudness was loud or soft.

AMPLITUDE (cm) LOUDNESS (relative)

1 cm Soft Loud10 cm Soft Loud

ConclusionAs the amplitude _______ _____

the loudness of a sound __________.

This is known as a _______________ relationship.

Exit Ticket