Healthy Kids Activities - Ears #1

So this week is going to be about ears and eyes.  I am combining the 2 so I can move on to better stuff next week.  So it will be brief but good! :)

You need playdoh for this activity.  You also should print this Diagram on the EAR HERE.

We stamped everyone's ears with playdoh then we discussed what each part of the ear does.

The Books we are reading are from the Library.  We liked...Hearing by Sharon Gordon, The Ear Book by Al Perkins, and My Ears by Lloyd G. Douglas. I am sure there are more out there, these are just the ones I picked up.

Outer Ear - These are the bits we can see, and also the ear canal. They act like a funnel to catch sound waves and direct them to the ear drum.

(A canal is a pathway for water, but the ear canal is a pathway for sound)

Middle Ear - This is a small air-filled space on the inside of the eardrum.

There are 3 tiny bones called ossicles in this part.

They are called the hammer, anvil and stirrup (because that is what they look like).

When the sound waves move the eardrum, these bones move and pass on the vibration to the very much smaller oval shaped window of the cochlea (the bit that looks like a shell). The hammer is touching the ear drum so it shakes when the sound comes through, and the movement goes right through the anvil to the stirrup, which is touching the cochlea.

Because of the difference in size between the eardrum and the oval window, the middle ear is very good at changing vibrations in the outside air into vibrations in the watery fluid inside the cochlea (you can tell, if you put your head under the sea, pool or bath water, that sound does not usually pass very easily from air to water).

Inner Ear -The cochlea has fluid in it, which moves and bends hairs on the outside of cells. There are about 17,000 hair cells in each ear, so they really are tiny. They are not like the hair on your head

Some of these hair cells (the 'inner hair cells') create an electrical impulse(signal), which is sent along the auditory nerve to the brain. Most of them (the 'outer' ones), however, are like tiny muscle cells, which react to the vibrations in the fluid by trembling and shaking; in this way they work like high quality amplifiers and make the vibrations much stronger and clearer for the smaller number of inner hair cells.

The brain then works out what you are hearing.

	The semi-circular canals in your inner ear contain fluid too.
	They send messages to your brain to help you keep your balance when you move.

(all of this information is from...Children and Womens health services.