We all know that some things float and some things sink. Boats float and spoons sink. Wood floats and paper sinks. I don't think this experiment will work, because we have to find out if paper clips can float. This project may turn out to be a "gotcha!" We all know that paper clips don't float. Needles don't float, either.

We have a wide-mouthed glass of water onto which we are supposed to very gently place a paper clip. Go ahead and do it, then watch it sink right to the bottom.

Oh oh! It's a gotcha, all right. On me! I didn't know as much as I thought I knew! That paper clip is staying right up there, on top of the water! Wow! Let's try a needle, and see what happens. Fooled again! It stays up, too! How can that be?

Let's look very closely at the surface of the water. Does it have a film? It sort of bends under the weight of the paper clip, doesn't it. The liquid is, again, doing its trick with surface tension. Surface tension is what is holding up the items that we know will not float.

That is a pretty good trick!

Now, lets float a piece of tissue paper on the surface of the water, and very gently place a paper clip onto the tissue. We know that the paper will absorb the water, and it would seem that the paper clip would sink right along with it.

That is really a trick! The tissue absorbs water and sinks, and the paper clip stays right up on top!

Surface tension can do a lot of tricks. I wonder what else it can do?