SOUND
- Q. Why is the speed of sound in air called Mach 1?
- A. It is named after Ernst Mach, a scientist who studied supersonic missiles in the late 19th century.
- Q. What is thunder?
- A. Thunder is the 'push' of sound waves from lightning.
- Q. Why do we hear thunder some time after we see the lightning?
- A. The speed of light is much faster than the speed of sound, so we see the lightning long before we see hear the thunder.
- Q. Why is your voice distorted if you speak into a moving desk fan set at a distance close to you?
- A. Sound is vibrations of air. Since the air is moving around a fan, this will distort the waves of sound, so your voice sounds strange.
- Q. Why did American Indians put their ears to the ground to hear if the cowboys were coming?
- A. Sound travels faster through solids than through the air, so the Indians could hear the cowboys even before they could see them.
- Q. What is a whip crack?
- A. The tip of whip travels faster than the speed of sound, creating a sonic boom.
- Q. How many telephones were invented by Alexander Graham Bell?
- A. Two (Ha!Ha!)
- Q. Why do cars coming towards you sound different to cars travelling away from you?
- A. This is called the Doppler Effect. As a car comes towards you, the sound waves also come towards you and are squashed up so you hear a higher frequency. As the car moves away from you so do the sound waves, they become more widely spaced apart. You hear a lower frequency.