Finally, we’re done with the basics of energy and can get down to some fun stuff. Now that you folks know what energy is all about you can begin to reap the rewards. The next few lessons are going to focus on sound. Sound is a form of energy. In this lesson we will focus on our sound antennas, our ears.

Sound Antennas

Energy is everywhere. As you sit reading this there is energy all around you in the form of sound waves, radio waves, television waves, cosmic rays, cell phone waves, wireless phone waves, etc. (By the way, except for sound waves the rest are all forms of electromagnetic waves. We will get to those several lessons down the line.) If you could somehow see all the energy that is around you all the time it would look like a constantly moving foggy haze of energy. Most of which goes through walls and some of which goes through you!

For better or for worse, we can’t detect all that energy. We can only detect energy in the form of sound waves and a small bit of electromagnetic waves (light and heat). For a radio to detect radio waves, it needs an antenna. The radio then takes the waves and, using the electronics inside the radio, turns the energy to sound energy. If the radio didn’t have the antenna, it couldn’t pick up the waves. The antenna alone couldn’t make anything out of the waves. Our ears are the same way. Our ears are our sound antenna. They pick up the sound waves. Nerves carry them to our brain, and our brain changes them to our perception of sound. Our eyes do the same thing with light, and our skin does the same thing with heat (another form of electromagnetic energy). These three antennae: ears, eyes, and skin, detect the outside energy. Our brain turns these detections into what we perceive as sound, light, or heat. Our antenna capture energy and our brains turn that into our perception of reality. Kinda neat, huh? Now here’s a new look at an old question: If a tree falls in the woods and there is no animal with ears around to hear it, does it make a sound? My answer to that question is “no”. The falling tree makes air compressions/sound waves, but if there is no antenna there to pick up the energy, and no brain there to interpret the energy, then there is nothing there to turn the sound waves to sound. Just like in your house right now, there are radio waves all over the place. If you don’t have a radio to catch those waves and turn them to sound, then there’s no sound.

Ears and Sound

Our ears are very good antennas. They are very effective at picking up quiet, loud, high-pitched and low-pitched sounds. It is difficult for people to make microphones that are as sensitive as our ears. Our ears can pick up and tell the difference between sounds as low-pitched as 20 Hz and as high-pitched as 20,000 Hz. Some animals can hear things that are even higher or lower pitched than that. Our ears and brain are also very good at picking out the direction a sound is coming from. Let’s play with our ears a little bit.

Experiment 1

Where Was That?

You need:

Any noise maker (an electronic timer with a high pitched beep works very well)

A partner

A blindfold (not necessary but more fun if you have one handy)

1. Sit or stand in the middle of a room.

2. Close your eyes or put on the blind fold.

3. Have your partner walk to another part of the room as quietly as possible.

4. Have your partner make the noisemaker make a noise.

5. With your eyes still closed, point to where you think the sound came from.

6. Try it several times and then let your partner have a turn.

How well did you do? Probably pretty well. Your ears are very good at determining where sounds are coming from. The reason your ears are so good at detecting the direction of a sound is due to the fact that sound hits one ear slightly before it hits the other ear. You brain does an amazing bit of quick math to make its best guess as to where the sound is coming from and how far away it is. Let’s do a little more with this.

Experiment 2

Tricking Your Ears

You need:

Any noise maker (an electronic timer with a high pitched beep works very well)

A partner

A blindfold (not necessary but more fun if you have one handy)

1. Sit or stand in the middle of a room.

2. Close your eyes or put on the blindfold.

3. Have your partner walk to another part of the room as quietly as possible.

4. Have you partner move the sound maker around the room like before, but this time make sure your partner makes the sound directly in front of you, behind you and over your head as well.

5. With your eyes still closed, point to where you think the sound came from.

6. Try it several times and then let your partner have a turn.

Did you get fooled this time? This works sometimes, but not always. What I hope happened was when the noisemaker was above your head, directly in front of you or directly behind you, you had trouble determining where the sound was coming from. Can you guess why this might have happened? Your ears are placed directly across from one another. If a noise happens directly in front of you, it hits your both ears at the exact same time. Your brain has no clues as to where the sound is coming from if the sound hits both ears at the same time so it makes its best guess. In this case, its best guess may be wrong. Let’s try one more thing here.

Experiment 3

Uni-ear

You need:

Any noise maker (an electronic timer with a high pitched beep works very well)

A partner

A blindfold (not necessary but more fun if you have one handy)

Ear plugs, if you have them (a finger will be okay if you don’t.)

1. Sit or stand in the middle of a room.

2. Close your eyes or put on the blindfold.

3. Put an ear plug in one of your ears. If you don’t have one, use your finger to cover your ear. Be very careful not to put your finger into your ear. Just use your finger to cover the hole in your ear.

4. Have your partner walk to another part of the room as quietly as possible.

5. Have your partner make the noisemaker make a noise. This will work best if the noise is not too loud.

6. With your eyes still closed, point to where you think the sound came from.

7. Try it several times and then let your partner try to find the sound.

How did you do with just one ear? Did you get fooled a little more often this time? Your brain has fewer clues to work with so it does the best it can with what it has.

Ears and Frequency

When it comes to sound, the frequency of the wave determines the pitch of the sound. The higher the frequency, the higher the pitch. The lower the frequency, the lower the pitch. The bark of a chihuahua has a much higher frequency sound wave than the bark of a rottweiler. We will do a little more with this in later lessons (don’t worry, you don’t have to buy a dog). For now, I just want to show you how good your ears are at telling the difference between very close frequencies. So, let’s try it.

Experiment 4

You can Tune a Piano but can you Tuna Fish?

You need:

A piano or a keyboard (if you don’t have one try this website for a virtual one http://www.pianoworld.com/fun/javapiano/javapiano.htm)

Piece of paper

Pencil or pen

A partner

I’ll play the piano for you at www.handsonlinelearning.com/movies.

1. The object of this is to test how well you can tell the difference between different pitches/notes on a piano. Have your partner go to a piano while you get ready with a pencil and paper.

2. Have your partner play a note. Listen very carefully to the note, your partner can even play it more than once if you’d like. Then have your partner play three more notes. One of the next three notes should be the same note as the very first note.

3. Your job is to try to hear which of the three notes matches the first note. Write down whether note 1, 2, or 3 is the matching note.

4. Try it several times.

5. Switch places and let your partner try.

How did you do? Chances are you did pretty well. Your ears are amazing at detecting the smallest differences in sound frequencies. With practice you can get even better at telling the differences between notes.

Thanks to your sound antennas you can pick up sound energy all around you. They, in combination with your brain, work amazingly well to determine the pitch, loudness, and direction of sound. Yea for ears!

Energy is all around us all the time.

Antennae are necessary to pick up energy.

Our bodies have three antennae; eyes, ears, and skin.

Eyes can detect light waves, which are a small portion of the electromagnetic spectrum.

Skin can detect heat, which is another even smaller portion of the electromagnetic spectrum.

Ears can detect sound waves.

Our antennae pick up the energy, sound waves, heat, or light. Our brain interprets them.

Since we have two ears we are very good at determining the direction of a sound.

Our ears are also very good at telling the difference between sound frequencies.

1. Which of our body parts function as antennae?

2. Why do I call those antennae?

3. Why do we have two ears?

Answers

1. Our antennae are our ears, eyes, and skin.

2. Antennae pick up energy. Our eyes, ears and skin all pick up energy. Our brain then interprets the energy as light, sound or heat. By the way, you may be asking, “What about the nose? Is our nose an antenna”? Not in my opinion. Molecules have to come into the nose and land on smell sensors to register as a smell. Noses detect matter (molecules), not energy.

3. Our two ears, plus our brain allow us to be fairly accurate at knowing where sounds are coming from. The sound will hit one ear before hitting the other and our brain can do the math and figure out which direction