When I went out to check the ice mobiles late nast night they were melting fast; you can see the water dripping from the bottom of this one.

However, I was surprised to find that the one with brown leaves was still considerably largely than the one with green leaves and berries!  “Why would that be?” I asked myself.  After all, they were both exactly the same size; I had hung them out at exactly the same time and both were equally frozen solid.

In this photograph you can see how much bigger the lower one is than the higher one.

Surely a few inches in height hadn’t made any difference?  I looked back at the picture that I took when I first hung them out.

Mmmmm….. Could the orientation of the ice mobiles have anything to do with it?  The higher mobile is facing almost directly South.  How could I find out if this is what made a difference?

This surprise finding got me thinking.  What if I had followed the instructions on the Nature Detective site and boiled the water to make a clear mobile?  Would that have made a difference?  What if I had dyed the water I used so that the mobiles were different colours?  Would that have altered the speed that the ice melted?  What about the height that I hung them?    What if I made ice mobiles with salty water?  What if I made them with sugary water?

So many ‘What Ifs’.  I think that the best science lessons start when children generate lots of ‘What Ifs’ for themselves and then think of their own ways to find out.   How do you encourage the children in your class to ask “What if……?”

This morning the ice mobiles were gone.  There was no sign that they had ever hung in the apple tree; my experiment was over.  Tomorrow I’ll tell you about an icy experiment with my class that lasted for more than a fortnight!