"Sinkin' Lincoln" Lab

by E. S. Belasic

Objectives:

• to define surface tension

• to determine what factors affect surface tension

• to collect data on how many drops of water a penny can hold

Materials:

• pennies

• paper cups with water

• dropper bottles with clean water

• dropper bottles with soapy water

• paper towels

Pre Lab Questions:

1. What is surface tension?

2. How many drops of clean water do you predict a penny can hold?  _______

3. Soapy water?  _______

Procedures:

1. Take your penny and rinse it well in the paper cup with clean water.

2. Dry it very thoroughly!

3. Place your penny flat on the table, heads or tails up.

4. Begin to add drops of clean water.  Record # of drops in Table 1.

5. Clean penny. Repeat 2 more times.

6. Repeat using soapy water.

7. Place data (average) on stem and leaf on board.

Data:

Table 1: Number of drops (half page)

Figure 1: Stem and leaf of class data - clean water drops (half page)

Figure 2: Stem and leaf of class data - soapy water drops (half page)

Table 2: Summary data table of average drops (half page)

Analysis/Results:

1. Describe your findings using class data.
2. How would you explain what happened?
3. Does soap make a difference?
4. Do you think we'd get the similar results if we used nickels? dimes? quarters? oil? Explain.

Conclusion: 

In 2-3 sentences, explain what you learned in this lab.

This lab has been modified from its original version.