Floating Needle

If you try to float a needle in a bowl of water, you can’t do it without help, because the needle is too heavy and narrow. But if you lay it on a small piece of tissue and lay the tissue on the water, when the tissue sinks, the needle will continue to float!

This works because of what’s known as surface tension. The molecules at the top of the water pull on each other, making its surface act like a kind of thin, elastic skin. If you look closely, you can see a “dent” in the water where the weight of the needle is pushing down on it. Eventually the needle’s weight will break the “skin,” and the needle will sink.