Let’s see how much you’ve picked up with these experiments and the reading – answer as best as you can. (No peeking at the answers until you’re done!) Just relax and see what jumps to mind when you read the question. You can also print these out and jot down your answers in your science notebook.
Some of these questions you might recognize from the last lesson on potential energy, but we put them here again so you can see how they are inter-related. Have fun!
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Section One:
1. Which of our body parts function as antennae?
2. Why do I call those antennae?
3. Why do we have two ears?
Section Two:
1. Sound travels by waves. Transverse or longitudinal waves?
2. Sound travels faster in air, water, or solids?
3. Why does sound travel faster in that medium?
4. Would sound travel faster on a hot day or a cold day? Why?
5. Which travels faster, light or sound?
6. If you see a firework and hear the sound one second later, how far away is the firework?
7. If you see lightning and hear the lightning 10 Mississippi’s, uh I mean seconds, later, how far is the lightning?
Section Three:
1. If sound is a form of energy, what’s moving?
2. All sound comes from what?
3. What kind of a wave is sound?
4. What does frequency have to do with sound?
5. What does amplitude have to do with sound?
Section Four:
1. What causes sound?
2. What vibrates?
3. What is natural frequency?
4. Why do objects make different noises if they are hit or dropped or plunked?
5. What three things determine something’s natural frequency?
6. What is resonance?
7. If something is vibrating at 30,000 Hz, can we hear it?
8. What happens if energy is continued to be put into something resonating?
Need answers?
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At high latitudes, sensitive radios that are tuned below 5 MHz can detect three different types of radio emissions from the Earth’s ionosphere. While this is normally below the range of human hearing, if you could hear it, it would sound like static bursts and squawks. NASA has been studying these for years: http://istp.gsfc.nasa.gov/istp/news/0112/fall01agu.html
Thank you. I did not know the sun makes noise. Can we hear the northern lights… do they make sound? The Inuit say they can hear it sometimes.
30,000 Hz is usually beyond our ability to hear it – most adults top out around 15,000 Hz because of hearing damage (music was too loud as a teenager, stood too close to a jet engine, hours of rocking screaming babies, etc…) You can translate the 30,000 Hz sound to something within our range and still call it 30,000 Hz, but it’s not a true 30,000 Hz. That’s one way that I have folks ‘hear’ the sound of the sun – I capture the radio range which is at lower frequencies and bump it up to audible range. Does that help?
7. If something is vibrating at 30,000 Hz, can we hear it?
Your answer is no but it seems we can hear it when listening to it on you tube. Why is that?