Water - Investigation 1: Water Observations
Part 2: Surface Tension

Teacher Background

• Surface tension is the skinlike surface of water that pulls it together into the smallest possible volume.
• Drops of water form domes on pennies because of surface tension.
• Surface tension can be disrupted by the addition of some other substances.
• Teacher Observations:  Check for understanding of surface tension and reporting results honestly.

Set-up/Management Tips

1. Rinse pennies in vinegar to make sure there is no soapy residue.
2. Discuss as a class how the high the dropper should be from the penny.
3. A flex cam is a good piece of technology to use with this investigation to show detail.
4. Remind students not mix soap droppers with the plain water cups.

Literacy Support

A Drop of Water:  A Book of Science and Wonder by Walter Wick

Science Stories

Read “Surface Tension.”

Scientific Vocabulary

The following words are key vocabulary words that will be introduced in this lesson and reinforced throughout the unit:

• surface tension
• dome