Use bread bag ties to create boats that race along the surface of water without even touching them.
What you need:
- shallow dish, square or rectangular
- water
- bread bag clips
- food dye (optional)
- dishwashing liquid
- cotton tips
What to do:
- Pour the water into the dish so it covers the bottom of the dish.
- Place bread bag clips at one end of the dish.
- Add a drop of food dye into the hole of the bread bag clips (optional).
- Put some dishwashing liquid onto some cotton tips.
- Touch the cotton tip into the water, just behind the bread bag clips.
- The bread bag clips will shoot forwards, across the top of the water- have a race, which one will win?
What happens:
You could also try throwing the bread bag clips into the water – they will probably sink, however when you gently place them on the water, they float. This is because of surface tension. The surface of the water has molecules that are more strongly bound to each other than those in the bulk of the water, so even things that sink into the water can float on it’s surface. When the dishwashing liquid is added, it breaks down the surface tension, causing the water to spread, which propels the bread bag clips along the top. If you use food dye, this will also move around as the surface tension is affected.
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