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ZatsWhy (Answers) - The Everyday World

What is sound energy?
Why does ice split when put in water?
What comes out when wind and water are put together?
What came first - the chicken or the egg?

What is sound energy?
Sound energy comes from something that is “vibrating,” or moving back and forth very fast. For instance when you ring a bell, the bell produces sound because the ringer makes the metal of the bell vibrate. You can’t see the bell vibrating very well, but you can feel it if you put your finger on the bell while it’s still ringing. Your finger can make the bell start to quiet and you can make the bell quiet completely if you put your whole hand on it. The bell becomes quieter (or stops ringing) depending on how much your finger (or hand) stops it from vibrating. (For instance, if you put your finger on a quiet bell, you can feel that it’s not vibrating at all.) The ringing, vibrating bell sends out energy as it pushes on the air around it, first one way then the other, back and forth, really fast. This energy from the vibrating bell makes little “air waves” that go out from the bell sort of like how little water waves go out in all directions from the spot where you drop a rock into a pond. The difference with sound is that you can’t see the sound waves in the air coming from the ringing bell the way you see the water waves in the pond. Instead, we hear the sound of the bell because when the sound energy waves reach your ears, they make your eardrum vibrate the same way the bell is vibrating. Your brain automatically knows that a ringing bell caused the kind of vibration on your eardrum, so that’s what you hear even if you don’t see the bell! Sound energy waves travel through liquids or solids even better than they do through air. You can try it out yourself. Next time you and a friend are swimming, compare how well you hear finger snaps above the water and underwater. (It’s a fun surprise, I think.). Super question, Lena. Thanks.
by Jeff | Mon Mar 4 16:17:31 PST 2002 | Back to Top

Why does ice split when put in water?
I wondered about that myself, Joanna. Here’s why it happens. Even though a piece of ice looks solid all the way through, it actually has tiny cracks in it. When you put the ice cube in water, the water flows into the cracks and gets inside the ice cube. Once the water gets inside, though, the ice cools it down. Now you may have noticed that when water freezes, the piece of ice is bigger than the water was when you put it in the freezer. (Scientists say the water “expands” when it freezes.) The same thing happens to the water when it flows into the ice cube. As it freezes and gets bigger, the water pushes on either side of the crack in the cube until it splits the ice! Good question, Joanna. Thanks!
by Jeff | Tue Nov 20 12:12:33 PST 2001 | Back to Top

What comes out when wind and water are put together?
There are a couple of ways of looking at wind and water combining together, Dan. Where do we see air moving (wind) with water in it? I live in the San Francisco bay area, and we see a lot of fog in this part of the world, often moving in with the wind from the sea. The fog is really made up of little drops of water, so “fog rolling in” is one thing that can happen when wind and water are put together. In that same way, a rainstorm or snowstorm with a lot of wind is also wind and water put together. Your question also brings up another idea that’s very important in the world around us. In our world, water is constantly moving around and changing forms in a process that scientists call the “Water Cycle.” Water falls from the clouds to the ground as rain or snow, and some of it collects into rivers and streams. The water in the rivers and streams flows until it collects into lakes or oceans. All during this time, some of the water is “evaporating” or turning from a liquid into a gas (what scientists call “water vapor”). Evaporation happens even more in the lakes and rivers where there is a lot of water spread out over a big area. When it’s hot out, more water goes from liquid to water vapor. Wind can increase evaporation when it blows across the surface of the water, too. Plants are also helping this process. Plants pull water out of the ground (the water that didn’t run off into the streams and rivers) and some of it comes out on their leaves and evaporates into the air. (Scientists call this process “transpiration.”). The water vapor in the air forms clouds, which are made up of little drops. The clouds collect more and more water, and they eventually release it back to the ground in the form of rain or snow. The whole process then starts over again. Water on our planet is always going through this big cycle all the time. Here are some links if you’d like to learn more about the Water Cycle: http://www.epa.gov/OGWDW/kids/cycle.html http://www.epa.gov/region07/kids/wtrcycle.htm http://mbgnet.mobot.org/fresh/cycle/concepts.htm Thanks for the question, Dan.
by Jeff | Fri Jan 25 11:27:54 PST 2002 | Back to Top

What came first - the chicken or the egg?
You may have learned in school that all living creatures have something called DNA. It is basically a blueprint for all the characteristics of you and your body. In nature, living things evolve through changes in to form a zygote - the first cell of a new baby chicken. This fils to make a complete animal. Chickens evolved from whatever came before chickens through small changes in their n see from this description that the egg came first. Prior to that first true chicken zygote, there were only animals similar to a chicken but not exactly a chicken. So, all this means that there were eggs before there were chickens, but these eggs weren't really chicken eggs until there were chickens to lay them. Want to learn more? Check out: Encyclopedia Brittanica on DNA http://www.britannica.com/eb/article?eu=31232&tocid=0 The Genetic Science Learning Center http://raven.umnh.utah.edu/new/projects/kitchenDNA.html
by Jeff | Tue Jun 12 14:54:15 PDT 2001 | Back to Top

What is WhyizZat all about?

WhyizZat is a fun site to learn about science and ask science questions. My name is Jeff, and I have been interested in science since I was in about the 4th grade. I like all kinds of science subjects, including how our bodies work, what makes up the world around us, what the stars and planets are like. I'm not a scientist myself, but I've learned a lot about science and what I don't know I can usually find out.

- Jeff Koppelmaa