anyone good at Sceince?!!?!!?!?!?

This better not be your homework, cheater -_-

1) The particles in metal are closer together, while the particles in air are farther apart. sound is caused 由 vibrations of the partcles. The particles would hit each other much faster in metal than in air, which is why it travels faster in metal.
2) They measure approximately how long it takes for the sound to reflect back from the food.
3) Sound waves need a medium (gas, solid 或者 liquid) in which to travel through. 太空 has no medium.
4) It means the frequency of the sound is 150 waves passing 由 per second. (not necessarily sure about this one)

Okay, I am not positive about these answers, but here's what I think:

1. Sound is really just vibrations, so it probably vibrates easier through metal than it does through open air.

2. They probably have really good hearing, so when they screech they can hear the vibrations hitting an object and based on what it sounds like and where it's coming from, they can know where it is.

3. In outer space, there is no air 或者 anything for vibrations to travel through to make sound.

4. I'm not sure, but the less hertz the lower the sound will be, so I'm guessing that 150 hertz might be a higher sound.

) Sound travels at different speeds in different substances. Why does it travel faster in metal than in air?
The speed of sound is not always the same. Remember that sound is a vibration of kinetic energy passed from molecule to molecule. The closer the molecules are to each other and the tighter their bonds, the less time it takes for them to pass the sound to each other and the faster sound can travel. It is easier for sound waves to go through solids than through liquids because the molecules are closer together and 更多 tightly bonded in solids. Similarly, it is harder for sound to pass through gases than through liquids, because gaseous molecules are farther apart. The speed of sound is faster in solid materials and slower in liquids 或者 gases. The velocity of a sound wave is affected 由 two properties of matter: the elastic properties and density. The relationship is described 由 the following equation.
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2) How do animals,like bats 或者 porpoises, use ultrasonic sounds to find their way 或者 to catch food?
动物 such as bats make ultrasonic noises which then bounce off the prey. The amount of time that the sound takes to come back enables the bat to judge their distance from the prey.

3) In outer space, there are no sounds. why?
Sounds requires a medium to travel through. An example is air. You've also heard sound travel through water and solid objects like wood.

In the past it was often thought that no medium exists in space. However, in current astronomy and astrophysics it is thought that dark matter is the medium 由 which sound can and does travel about space. Due to the atoms being so spread out though, the human ear would not be capable of detecting the sound waves.
For 更多 information check out:

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4) The hertz is used to measure the frequency of sound. If something is rated 150 hertz what does that mean?
link

here is a website to listen to some different frequencies. Unfortunately they don't have the "150" hertz frequency to listen to but scroll down, and on the right there are vawe charts, click on them and wait a sec, and then 你 should hear a 预览 of the sound, (you need quicktime)

The less hertz the lower the tone will be




Here 你 go, I hope this helps

Kowalski's good at science! xD

I only know 1 and 3 :P

1. Because metal is denser so it can travel faster through it than air.

3. There is no air in space. It's just an empty vaccum and sound needs a medium to travel through.


We're studying some of this stuffs right now... mostly waves (light, sound, radio, ect) ;)

im kinda good