) 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 madami 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 or gases. The velocity of a sound wave is affected sa pamamagitan ng two properties of matter: the elastic properties and density. The relationship is described sa pamamagitan ng the following equation.
link 2) How do animals,like bats or porpoises, use ultrasonic sounds to find their way or to catch food?
mga hayop 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 sa pamamagitan ng 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.
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link 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 you should hear a prebiyu of the sound, (you need quicktime)
The less hertz the lower the tone will be
Here you go, I hope this helps