My PBL Project

Materials:

• Water

• Pins

• Bowl

• Towel

4. After you pour all 1000 pins in the bowl, your bowl should produce a bubble over your bowl. It should look like this:

Procedures:

1. Assemble all the materials on a table.

2. Take the bowl and fill the bowl with water. The water should be all the way to the top of the bowl. It should look like this:

4. After you pour all 1000 pins in the bowl, your bowl should produce a bubble over your bowl. It should look like this:

3. Start to pour pins in the bowl. Don't put all the pins in at the same time because it might cause the water to overflow. Pour about 100 pins per time.

Surface Tension is now created!

Scientific Principle:

Surface tension is a contraction tendency of the surface of a liquid that allows it to resist an external force. It is revealed, for example, in the floating of some objects on the surface of water, even though they are denser than water, and in the ability of some insects to run on the water surface. This property is caused by cohesion of similar molecules, and is responsible for many of the behaviors of liquids.