How do science concepts apply to your world? Here are some questions you'll be able to answer after you read this chapter.

• Why can a snowblower remove snow faster than a person using a shovel?
• How can you lift a car using your hands?
• How does a nutcracker make it easier to crack a nut?
• Why are the trails up mountains constructed to be long and winding?
• Why do bicycles have gears?

How Do Ramps Help You Raise Objects?

Procedure

1. Make a stack of five books.
2. Make a ramp by leaning a short board against the top of the book stack. Place a sixth book against the bottom edge of the board to keep the ramp from sliding down.
3. Measure and record the height and length of the ramp.
4. Use a spring scale to pull a laboratory cart up the ramp at constant speed. Record the force indicated on the spring scale.
5. Repeat Steps 2 through 4 using a longer board.

Think About It

1. Comparing and Contrasting   Which ramp required a greater force to pull the cart? Which ramp required the cart to travel a greater distance?
2. Predicting   How do you think the force needed to pull the cart would change if the cart accelerated up the length of the ramp?
3. Formulating Hypotheses   Explain why a box that is too heavy to lift can often be pushed up a ramp.