Opening paper flowers

We started this experiment a few weeks ago and my son half-heartedly coloured in some flowers I had drawn with a permanent pen (Sharpie) then lost interest. I put them on one side and we came back to it later... We folded them in two different ways, some with the petals folded in half so the tips touched the middle of the flower, and the others with each petal folded into the middle going around the flower shape in a spiral.

Watching paper flowers open

We placed them on the surface of some water in a plastic tray from our recycling bin and watched as the flowers opened! This happens because the paper absorbs water and expands.  The swelling along the fold causes the paper to unfold. We found the petals folded in half opened faster than the ones in a spiral as each petal absorbed the water and unfolded independently rather than having to wait for the petals folded on top to move first.

More drawn with coloured Sharpie, folded two different ways

Our other finding was that the ones my son coloured with felt tip pen just before we put them in water were already too damp from the ink and didn't open, they just absorbed more water and sank! The ones he coloured several days beforehand worked fine as they had dried out completely (although the water soluble ink did come out into the water). My son was a little disappointed his most recent creations didn't open, and requested more of "Mummy's ones" without the felt tip. We did a few more, and he delighted in watching them open.

He liked this activity overall, but as I'd been hoping it would be a nice way to get him interested in colouring in, the failure of the recently coloured ones didn't work out like I'd intended!  It's still a nice simple and quick science activity though and I'm sure we will come back to it in the future.