"Sinkin' Lincoln" Lab

Liz LaRosa


updated pdf version of this lab 2008



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?  _______


  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 experiment using soapy water.

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


Table 1: Number of drops (half page)

  Trial 1 Trial 2 Trial 3 Average
Clean Water       drops
Soapy Water       drops

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)


  n max min range sum avg median
Clean Water              
Soapy Water              



  1. Describe your findings using class data.
  2. How would you explain what happened?
  3. Does soap make a difference?
  4. What other variables may be a cause for the differences in the number of drops each penny was able to hold?
  5. Do you think we'd get the similar results if we used different sized coins? Explain.
  6. Do you think we get similar results if we used different types of liquids such as oil or vinegar?


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

This lab has been modified from its original version.