Per Group
Place the RISE girls into cooperative groups of two or three. Have the girls work together and share the responsibilities of recording data and manipulating materials.
1. Tell the girls that they are going to create their own friction. Have
the girls rub their hands together for one minute. (The girls may start
complaining about how hot their hands are getting, but remind them that
sensations are also observations and they should make mental notes of all
their sensations for their observation log.)
2. As they are rubbing their hands together, ask the girls to describe how
their hands feel. Is there anything else that is happening? (Some girls
will rub off some of the dirt that was on their hands, which is another
property of friction. Friction causes the objects involved to wear away.)
3. Tell the girls to stop rubbing their hands. Have the girls put their
hands on their faces. How do their hands feel on their cheeks?
4. Explain that whenever the surfaces of two objects rub together (the hands
in this case) the resulting friction creates heat. (In this simple activity,
the heat is quickly observed and will vary girl to girl according to the
amount of moisture (perspiration and oil in the skin) that is present on
their hands.
1. Have the girls rub their hands as they did in activity one, except this
time put into the girls' hand a dab of hand lotion.
Have the girls rub their hands briskly for one minute.
2. Ask the girls how their hands feel. Are they hot like before?
3. Have the girls draw conclusions as to what are friction and lubrication.
Have them create their own definitions for friction and lubrication. (The
hand lotion acts as a lubricant, reducing friction, and thereby reducing
the amount of heat produced by friction. Reduction in friction resulting
from the use of a lubricant can also be demonstrated by applying a small
amount of olive oil or cooking oil to the palms of the hands before rubbing.)
4. Ask the girls to explain when friction was maximized, and minimized,
during this activity.
1. Have the groups try to spin a book on their table tops. Have them try to spin two or more stacked books.
2. Have them count how many completed spins they did in each trial. Record the group's results on the board.
3. Ask them what force is preventing them from being able to spin the book well (friction). Ask them if they need to minimize or maximize friction in order for the books to spin well.
4. Ask the girls to try to come up with a way that allows the book to spin more often than it already does. Have them share their ideas.
5. Pass out a metal lid from cookie/coffee cans and 6 to 8 marbles to each group. Have them put the marbles under the metal lid.
6. Next have them place the book(s) carefully on the metal lid.
7. Have the girls try spinning the book(s). Have them count how many spins they can achieve. Ask if they were able to accomplish more spins with the lid than without the lid. Record each group's answers.
8. Ask, "What did the lid and marbles represent? Did they maximize or minimize friction?" ( The lid and marbles represent ball bearings that reduced friction and allowed for greater movement.)
Friction is a force that causes two objects to resist movement over each other.
Friction is created when two things rub against each other. No surface is completely free of bumps and pits. The rougher the surface, the more friction is created as the bumps and pits slide past each other.
Making the surfaces smoother and/or applying lubricants are ways of reducing friction. Friction can also be reduced with the use of rollers or ball bearings.
 |
 |
 |
 |
 |
 |
| HomePage | Table of Contents |
Program Overview |
Starting a Girls RISE |
Explorations | Girls on the RISE |