Surface Tension

What You Need:

• Glass of water
• Dry paint brushes

Instructions:

1. Make sure the paintbrushes are dry.
2. Notice how the bristles of the paintbrush look while they are dry.
3. Now dip the tip of the brush into the water, and notice how the bristles are all pulled together at the tip now that they are wet.
4. Surface tension of water is strong, and pulls together the bristles and the water.

Note:

Notice that the softer “fluffier” brushes are more affected by the surface tension of the water. The stiffer bristles, like the ones on the purple brush, are more resistant to the tension.