Can you make a paperclip float in water? Your standard metal paperclip isn’t very buoyant and as you would expect, tends to sink in water. But with just a piece of tissue paper and a pencil you can make a paperclip float…
- Place a small piece of tissue paper in the water so it floats
- Carefully put your paperclip on the tissue paper without you touching the paper
- Slowly use the pencil to push the paper down so it sinks – try not to touch the paperclip.
- You should be left with a floating paperclip – but is it really floating?
Technically, the paperclip isn’t actually floating. It is held on the surface of the water by surface tension. Water molecules tend to attract one another and this forms a ‘skin’ on top where the water particles hold tightly together. This surface tension is strong enough to hold the paperclip. But if you poke the paperclip or shake the bowl, you break the surface tension and the paperclip will sink.
Pond skaters also use water tension to walk on water. They have evolved legs that distribute their weight evenly and so are adapted to life on the water’s surface.