I Need a Sceptic's Scientific Explanation of my Snowglobe

Post Reply New Topic

OK, first of all I'm not the type to believe in ghosts. I'm a humanities graduate though and don't understand much about science.

I'd like a scientist or just someone with more science knowledge than me to give me a rational explanation for what's going on with my snow globe. It's not freaking me out but it is making me curious as to how it works.

I live in a cabin which is outside and in a country where it's cold at the moment.

There's a snow globe on my shelf. It isn't an electronic one or a battery one. It's wind up. Usually, to get it to work, I have to wind it up.

My magical thinking explanation is I haven't played with it enough this year and it's started to play by itself. But rationally I know this to be a nonsense.

Thing is though, I have no rational explanations for the reason why something which works through being wound up would start to work without being wound up.

What's going on isn't that it's tipping the snow up on its own. It's simply playing music.

I'd like a scientist/scientific mind to explain this to me in lay person's terms.

How much is it playing? Just a note or two? Or a few minutes?

Heat and cold cause things to expand and compress...it could simply be a matter of the metal inside shifting around a tiny amount.

Sounds a bit strange at any rate.

Even if it played a slightly longer segment, it's possible that the mainspring didn't fully unwind last it was wound up, and shifting temperatures released what tension remained.

It's a few notes.
Hmm probably a temperature thing then, interesting.

I concur with what the others have said. Here is an official explanation from Sara Al-Assam, Student, Tiffin Girls' School, Kingston:

Recall that all materials are made up of atoms. At any temperature above absolute zero (-273 degrees celsius) the atoms will be moving. In a solid they will be vibrating in fixed positions, in a liquid thy will be jostling past each other and in a gas they will be whizzing past each other at very high speeds. When a material is heated, the kinetic energy of that material increases and its atoms and molecules move about more. This means that each atom will take up more space due to its movement so the material will expand. When it is cold the kinetic energy decreases, so the atoms take up less space and the material contracts.

Some metals expand more than others due to differences in the forces between the atoms / molecules. In metals such as iron the forces between the atoms are stronger so it is more difficult for the atoms to move around . In brass the forces are a little weaker so the atoms are free to move about more. These differences in contraction are used in a bimetallic strip, which is composed of a strip of brass laid along side strip of Iron. When the strip is heated the brass expands more than the iron so the strip beds. It is used in devics such as fire alarms and circuit breakers to either make or break contacts in an electric circuit.

Source: Expansion and Contraction : Why does heat and cold make things expand and contract ? Also why do some metals expand more than others?

Definitely the metals, I bet it hasn't unwound itself all the way yet and if you forcefully unwind it, you'll see there's still some unwind left in it. A wind up gear works by twisting and stretching the metal around itself so that pressure builds up and causes it to unwind, playing the music. Depending on the temperature of the metal, it could expand or contract enough on its own to slightly wind or unwind further, playing a few notes.

Ever hear your pipes banging in your walls sometimes? That's because the hot or cold water has finished passing through them and they're returning to their normal temperature again, contracting or expanding and knocking against the pipe next to them. This is easily avoidable by properly anchoring the pipes, by the way.