Why did the fork balance?

Every object has a centre of mass — a point where its mass is balanced around.

Because a fork is not the same shape or thickness all the way along, its centre of mass may not be exactly where you expect.

When you balanced the fork on your finger, you were searching for its balance point.

What happened when you added Play-Doh?

Adding Play-Doh changed where the fork's mass was located.

When you moved the Play-Doh, the balance point moved too. Changing the amount of Play-Doh could make an even bigger difference.

You discovered an important rule:

Balance depends not only on how much mass there is, but also on where that mass is positioned.

How can the fork sculpture balance on a glass?

When the two forks are joined together, their mass spreads out around the wooden skewer.

If everything is positioned in just the right place, the centre of mass of the whole sculpture allows it to balance on the tiny edge of the glass.

It might look impossible, but gravity is still pulling everything down towards Earth.

The secret is how all that mass has been arranged.

Can you change the balance?

Absolutely!

Moving the Play-Doh, changing its amount or adjusting the forks changes how the mass is distributed.

Sometimes a surprisingly small change is enough to make the sculpture tip over.

That's why scientists and engineers don't just think about how heavy something is — they also think about where its mass is located.

And there's even more physics hiding inside this balancing trick...