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In this exhibit you learn about how the shapes of some objects make them move differently to how we'd expect.
A Tippy Top is a small spinning top which, when spun fast enough, will eventually flip over and spin on its stem. It is sold as a toy, but is also of great interest to physicists.
The Tippy Top flips over because it is more stable on its stem, than it is on its round end. As it spins, it wanders about the table, which means that its axis of rotation is not in line with its point of contact with the table, and this makes it unstable. This causes the Tippy Top to flip over into a more stable position.
As the Top flips over, it slows down. This is because it has used some of its spinning energy to lift it up. This is why it is important to get the Tippy Top spinning very fast: if it's going too slowly it won't have enough energy to lift up.
There are also many naturally occuring Tippy Tops. Hard boiled eggs function as Tippy Tops and will lift up onto one end if spun. Egg shaped stones behave similarly. In South America, people play with a small round fruit with a stem. If the fruit is spun by its stem, it will flip over and spin on its stem.
The toy Tippy Top was invented in Germany in 1891, but didn't become popular. It was invented again in 1950 by a Danish scientist who had seen the South American fruits. At that point, the Tippy Top took off, and was sold as a toy, given away in breakfast cereal and put into Christmas crackers.
Although a toy, the Tippy Top was an object of fascination to many scientists. Niels Bohr and Wolfgang Pauli, two great 20th Century physicists, were both entertained by the Tippy Top. Politican Winston Churchill was also a fan.
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Questions
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| 1 |
When spun, a Tippy Top ________ over and spins on its ________. |
| 2 |
Which is a more stable position for a spinning Tippy Top, on its round end or its stem? |
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Why is it important to spin the Tippy Top very fast? |
| 4 |
Where are Tippy Top-like fruits played with? |
| 5 |
The Tippy Top was invented twice. In which two years was it invented? |
| 6 |
Find out who Niels Bohr and Wolfgang Pauli were and what they discovered. |
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Activities
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| 1 |
Spinning eggs is a way to find out if they've been hard-boiled or not. Get a hard-boiled egg (about 5 min in boiling water on the hob then allow to cool) and an uncooked egg. Spin both eggs on a hard surface (try the floor: you don't want to be dropping raw eggs off a table). The raw egg will spin on its side, but the boiled egg will lift up onto its end, like a Tippy Top. The sloshy contents of a raw egg mean its centre of gravity moves so it is stable on its side. |
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You can make a Tippy Top out of four marbles and some strong glue. Glue the marbles together into a tetrahedron (pyramid) shape. Once the glue is dry, spin the Top on a hard surface. The Top will lift up and spin on a single marble. If you use different coloured marbles, you can see how they move. |
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