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Where’s your head at? Our ability to sense the rotational movement of our head comes from a set of organs in the inner ear. One of these organs, the utricle, also gives us the ability to sense acceleration. Our latest video takes a look inside our ears, and how you can make a device to mimic this sense of acceleration.

Video transcript available here.

Inside your ear, this set of organs is called the vestibular system, where you have three semicircular canals oriented in three different directions. When your head turns, thick fluid moves within the semicircular canals, bending a cluster of hairs located at the base of each canal. The bending of these hairs transmits signals to your brain, giving you a sense of balance. A second organ, the utricle, uses a similar system of fluid and hairs to give us the ability to sense acceleration.

The homemade accelerometer works on the same principle these organs use to sense acceleration. The water inside the container is just like your ear fluid, the cork just like that cluster of hairs.

Inside the accelerometer, the fluid moves the cork and string in the opposite direction.  When you reach a constant speed, the cork and string bend back to being vertical. Measuring the angle of the string can give you an idea of the direction and amount of acceleration.

Teachers notes with curriculum links are available here.