Paper towel
Bucket of small stones
Scientific method worksheet (below)
Clear drinking glasses
Masking tape


I will present three different types of "challenges" today to encourage the students to think creatively and to work as a team.  Students will be broken up into groups of 3-5.  Emphasis is placed on teamwork, thought process, a common goal, and creativity, rather than a specific "right" or "wrong" answer.

Challenge I
Two glasses will be placed approximately 8 inches apart.  The first one contains ice floating in water, while the second one is empty.  Students are told that they are to move the ice from one glass to the next without touching the ice or the glasses.  First, have the students state the problem on the scientific method sheets.  Second, their group must design a hypothesis.  Third, they must write this idea on the scientific method worksheet (simply to ensure that the student actually use the scientific method and think about what they are about to do), and then they may test their hypothesis.  If the hypothesis fails, they must go back and think of a new way to solve the problem.

Students were extremely creative with this challenge.  Some used the nail and toothpick to pick up the ice cube (not an easy task); others created elaborate slings with the string and toothpicks, and one group used the salt and melted the ice around the string, thereby freezing the string to the cube, and carried it over.

Challenge II
Again, two empty glasses should be placed approximately 8 inches apart.  Place a piece of tape between the center of the glasses.  The students are told they must get the water from one glass to the next without touching the glasses.  First, allow them to cross the line with their hands.  Most will solve this pretty quickly by wringing out the water from one glass to the next.  Next, issue the same challenge, but prevent the students from crossing the line.  The secret to solving this problem is to utilize the paper towel and show the effect of capillary action.

Challenge III
This experiment is a simple one that demonstrates surface tension.  Have each of the groups grab a handful of small pebbles.  Fill each of the glasses to the rim with water.  Then ask the students how many stones it will take before the water flows over the sides.  Take a poll throughout the class and write down the results.  Almost inevitably, the students will underestimate the number of pebbles (often by huge amounts), since they assume the water can only fill up to the sides of the glass.  As a hint, when adding the stones, have the students place them in one at a time at eye level to ensure they can see the "rounding" of the water over the sides of the glass.


The Scientific Method

What is the problem that you are observing?

How do you propose that this problem be solved?

Perform the test using the hypothesis that was designed.

How well did your hypothesis work?  If it wasn't successful, think of another hypothesis and repeat the test.

Shawn Len, 2000.