Yr9 Waves - Ear & Eye

Question 1

Discuss how the ear works.

Answer 1

Sound waves travel by particle vibrations. When a particle vibrates it makes the particle next to it vibrate. The pinna focuses these vibrations into the ear canal where the vibrations travel through the air and cause the ear drum to vibrate. The small bones in your ears move back and forth while the ear drum vibrates. The movement moves the membrane at the other end of the cochlea. The cochlea is filled with a liquid that vibrates and moves little hairs also inside the cochlea. The movement of these hairs is transferred into electrical signals that are sent to the brain by the auditory nerve. The brain translates these signals into the sounds we hear.

Question 2

Discuss how the eye works.

Answer 2

Light rays travel to the cornea. The cornea is transparent to let the light through, but tough to protect the inner eye. Then the light passes through the pupil. The pupil is a hole that is controlled by the iris muscle. The iris can close to prevent too much light damaging the retina. The light then passes through the lens. The lens is a clear structure that refracts light rays and converges them through the vitreous humor and onto the retina. The retina is the back lining of the eye of the eye that contains light sensitive cells. These cells convert light falling on them into electrical and nervous messages. These messages are then sent to the brain.
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