LabLearner—The Science of Learning
LabLearner—The Science of Learning

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Earth’s Forces

Investigation 3 – Lab

 

 

 

 

 

 

 

Back to Investigation 3

BE PREPARED

 

Group materials:
  • 1 acrylic cylinder
  • 1 metric ruler
  • 1 meter stick
  • 2 sheets of sandpaper
  • 1 roll of masking tape
  • 1 wood block
Individual materials: 
  • 1 Student Data Record

Teacher Preparation

  1. Place all materials at the distribution center.
  2. Divide the class into five (5) cooperative groups.

Instruction

  1. Direct each student group to obtain the following necessary materials from the distribution point: one (1) meter stick, one (1) metric ruler, 2 sheets of sandpaper, one (1) roll of masking tape, one (1) wood block, and one (1) acrylic cylinder.

GET FOCUSED

  • Students will perform experiments to explore the effect of different surfaces on friction.
  • As students perform their lab experiments, they should keep the following question in mind:

How does surface type affect friction?

INVESTIGATE

Trial 1

In Trial 1, students will create a ramp using the woodblock and ruler. Students will measure the distance that an acrylic cylinder will roll when released from the ramp onto the tabletop surface. The following steps are included to guide students through the Trial:

a. Students will create a ramp by placing the wood block so that it rests on its largest side.

b. The metric ruler should be placed with the 0 cm end on the tabletop and the 28 cm mark on the edge of the woodblock. If necessary, remind students of the Procedural Tool, Metric Ruler Use and Operation.

c. The meter stick should be placed 3 cm to the side of the metric ruler so that the 0 cm mark on the meter ruler begins where the 30 cm ruler touches the table. If necessary, remind students of the Procedural Tool, Meter Stick Use and Operation.

d. To begin the trial, students should hold the acrylic cylinder by its flat sides. It should be held so that it rests on the metric ruler. The front edge of the cylinder should be at the 3 cm mark on the ruler.

e. Caution students to let go of, but should not push, the acrylic cylinder. Students should record the distance traveled across the table in Problem 4 of the Student Data Record.

f. Steps d and e should be repeated two more times. Students should perform a total of 3 runs on the tabletop surface and record the distance each time in the table in Problem 4 of the Student Data Record.

Trial 2

The frictional force between the acrylic cylinder and masking tape.

a. Leave the ramp and the meter stick in position.

b. Place the masking tape on the lab table. There should be no ridges in the masking tape, and no gaps between each strip. The ruler should sit on top of the masking tape.

c. Hold the acrylic cylinder at the 3 cm position on the ruler and let it go. Do not push the acrylic cylinder.

d. Use the table on the previous page to record how far the acrylic cylinder traveled along the masking tape before it stopped.

e. Repeat steps 5c and 5d two more times. Record the data in the table.

Trial 3

The frictional force between the acrylic cylinder and sandpaper.

a. Remove the masking tape.

b. Turn the two sheets of sandpaper over and tape them together.

c. With the rough surface side up, place two sheets of sandpaper on the table. Tape the sandpaper to the table.

d. Hold the acrylic cylinder at the 3 cm position on the ruler and let it go. Do not push the acrylic cylinder.

e. Use the Table in Problem 4 to record how far the acrylic cylinder traveled along the sandpaper before it stopped.

f. Repeat steps 6d and 6e two more times. Record the data in the Table.

KEYS

CLEAN UP

Let students know your expectations for clean-up. Ask them to clean up.