### Phriendly Physics: An Invitation to Learn

BACKGROUND
The most basic aspects of physics contain a richness and depth that can be appreciated and explored without mathematics or with very minimal math. This activity, modified from one used in Phriendly Physics, encourages exploration and careful observation of an event that appears very simple but is actually quite complex.

Objectives:
Students will:

• use the techniques of inquiry to
investigate a physical phenomenon.
• explore a research topic of their
own choosing.
• make decisions as part of a group.
• observe events closely.
• learn to record their observations
and thoughts in an organized
manner.

MATERIALS (for each pair or group of students)

2 (or more) one-meter ramps. It helps to have a slight depression or "track" down the center of the ramp. A three-dollar molding strip will serve this purpose.

Books or blocks of wood on which to set one end of the ramps.
A wide variety of balls. Select different sizes and materials: large and small, heavy and light, hollow and solid, smooth, rough, and fuzzy.

Lab notebooks or journals and writing utensils.

Stopwatches (optional)

PROCEDURE

Have each group of students find a place on a table or the floor to set up their ramps. Using the materials they have on hand, they can investigate different areas of study such as mass, momentum and acceleration. It is very important that they write down everything they do. If you feel it is appropriate, you may want to assign specific tasks to members of the group, one of which would be the group recorder, who would write down everything the group does.

Then you circulate among the groups with the following objectives in mind: encouraging the students, assisting them as needed, and helping them record their results from their experiements. If students are having trouble focusing their investigation, you could prompt them by suggesting questions to investigate. Possible examples include:

• Is it easier to observe the behavior of the balls if the pitch of the ramps is steep, or shallow? Why? Can you think of a situation that would make shallow preferable to steep? What about the other way around?
• Does a stopwatch help you observe? Is there information you can obtain with a stopwatch that you can't obtain any other way? What is it? Is there information that you can get without using the stopwatch? What is it?
• What information would you be able to get if you made pencil marks on the ramp? Where would you place the marks? Why? Would you get different information if you placed the marks differently? How?
• Examine (look at, touch, squeeze, smell, bounce, etc.) a tennis ball and a steel ball. List all of the similarities and differences you notice between the two balls. Roll the two balls down the ramp at the same time. Look back at your list of similarities and differences. Which of those do you think were responsible for determining how the balls rolled down the ramps? Decide how you would test to see if you're right. Carry out your tests.

We strongly recommend that you make up your own questions to fit the level of the students and the direction in which they are steering themselves.

As a concluding activity, the groups could present their information to the rest of the class or propose another way of sharing what they have learned.