physics related ornament?

can someone help me think of a physics related ornament? i have to make it myself so can you also think of a easy one?

Try a tree with a falling apple, that should be simple.

Um... how about a laser that'll produce a monochromatic light, shooting through a diffraction grading film, and then through a series of mirrors and also a photographic gate, in order to measure the speed of light?

Aka A Big Vagina!

well, my teacher is going to put it on a tree so making a tree would be weird

Then just bring in an apple?

what??? how is that even related? here is an example: my friend said he is making like an atom model or something, like that do you understand

Make the same thing as your friend except tie an elastic band to the top so it can bounce up and down ON the tree.

you could possibly make a small newtons cradle out of marbles and fishing line with a frame made of popsickle sticks then put a string on the top to hang it from.