FRICTION 1

HYPOTHESIS

The heavier an object is, the more friction there is if you try to slide the object. Will more friction make it easier or harder to slide the object?

________________________________________________________

________________________________________________________

________________________________________________________

MATERIALS

2 science books1 bucket15 weights
1 loop of string1 hook

PROCEDURE

1. Clear off your desks. Get all of your materials.

2. Put the loop of string around one science book. See Figure 1.

3. Place the book about 1 inch from the edge of the desk with the string hanging over the edge. Attach the bucket to the string with the hook. See Figure 2.

4. Add weights to the bucket one at a time until the book moves or starts to slide. Be sure and add the weights gently. Record the number of weights needed in the chart below.

5. Repeat the experiment with a second science book stacked on top of the first one. Record your results.

NUMBER OF BOOKSPREDICTIONWEIGHTS NEEDED
1
2
3

6. Three books are heavier than two so there is more friction between them and the desk. Predict how many weights you will need to move three books.

7. Repeat the experiment to find out how many weights are needed. Record your answer. How does it compare with your prediction?

_______________________________________________________

_______________________________________________________

_______________________________________________________