Science -- Your Future, Scotland's Future
SCI-FUN Roadshow Exhibits -- Gyrowheel
SCI-FUN Roadshow Exhibits -- Gyrowheel
In this exhibit you learn that spinning objects behave differently to still objects. When you tilt the spinning gyrowheel you feel a strong resistance and you may even turn on the platform.

Spinning objects don’t like being moved because they want to keep on spinning in the same direction at the same speed. If you try to move a spinning object, the movement will transfer back to you.

A spinning object has something called angular momentum, which remains constant while that object is spinning unless an outside force (such as friction) comes in. If nothing else changes, the speed and direction (also known as velocity) of the spin will remain constant.

When you try to tilt a spinning object you are changing the direction of the spin. The direction of the spin is part of the angular momentum, which must remain constant. To keep angular momentum constant, the object resists the tilt. When you’re standing on the gyrowheel platform, that resistance transfers through you, and you turn as well.

In 1687 Sir Isaac Newton wrote his three laws of motion. We now know that these laws control the movement of every object we know of. The laws of motion are:

1 An object will continue to move in the speed and direction (velocity) it is moving, unless an outside force acts upon it. So when something is still (no velocity), it will stay still unless it is pushed or pulled. Or when it’s moving in a certain direction, it will keep going. Or, like the gyrowheel, when an object is spinning, it will continue to spin.
2 When a force is applied to an object, the force will equal the mass of the object multiplied by the acceleration of the object, i.e. how fast the object speeds up.
3 For every force that is applied to an object, that object exerts the same force back. So when we try to turn the wheel, the wheel tries to turn us back.

1 Spinning objects want to keep on spinning in the same __________ at the same __________.
2 How many laws of motion did Sir Isaac Newton come up with?
3 What do we call the speed of something when combined with direction?
4 According to Newton’s laws, what will a spinning object do if nothing happens to it?
5 What does an object do to you when you apply a force to it?
6 Can you think of another SCI-FUN exhibit that looks at angular momentum? What did you change in that activity to change your speed?

1 Get a spinning top (maybe you have younger relatives, maybe your parents kept hold of all your baby toys, or you might have one from a Christmas cracker). Get the top spinning, then gently nudge it – it will skid across the table but it won’t topple over.
2 Take your bike out to a big empty space. As you’re cycling along quite fast, slightly lean over to one side, without turning the handlebars. You won’t topple, because the angular momentum of the wheels is resisting you. You will turn in the direction you lean in. Watch a motorbike race on television: the riders never turn the handlebars, they lean in the direction they are turning.