1. The powerpoint of Sound We hear terrible, pleasant, loud, quiet, cute, annoying, and many more sounds everyday but, how and why? Picture 1

2. What is sound anyway? Sound is a type of energy made by vibrations. This energy collides with particles close to them to make sound waves. If your ear is close enough to the sound you can hear it. The sound waves keep going until the waves run out of energy. Like if you throw those small stones into the pond. The rings of waves expand forever. Same with sound. When the sound vibrations are fast, you will hear a higher note. When the sound vibrations are slow, you hear a low note. Sound needs something to travel through like air or water. So sound can’t be heard in space. You would need to know sign language. Sound travels through air at 340 meters (1,120 feet) per second. A reflected sound wave is an echo.

3. What organ lets us (humans) hear sound? The ear lets us hear sound. The ear is located on each side of your head, if you look at the person’s side of their face you will see their ear (if they have one). The diagram of the ear can be seen in Picture 2. Picture 2

4. How do we talk? We humans talk by making noises using vocal chords. If you still don’t believe me, put your fingers on your throat as you speak. Now you can feel something vibrate. That something is your vocal chords.

5. What is frequency and pitch? Frequency is the number of complete waves that pass a point each second. The unit of frequency is hertz. One hertz is equal to one wave per second. A pitch and a frequency are related. A sound’s pitch tells how high or low a sound is. A low-frequency sound has a low pitch. A high-frequency sound has a high pitch, vice versa. A toy whistle has a frequency of about 1000 hertz, so it has a high pitch. Thunder has a frequency of 50 hertz which means it is low- pitched. The frequencies that humans can hear is from 20 hertz to 20 kilohertz. This is called human hearing. Anything higher or lower cant be heard by humans. The unit of sound is decibel.

6. Sources Websites: http://www.sciencekidsathome.com/science_topics/what_is_sound.html Books: Concepts And Challenges: Physical Science

7. Credits Nothing much, It was a one person project, so Zaid Khan did everything.