www.TeachEngineering.org: Free Curriculum for K-12

> Home > Curriculum > Activities > Ramp and Review (for High Scool)

Activities may be standalone, or part of lessons or curricular units.

TE Activity: Ramp and Review (for High Scool)

In this hands-on activity — rolling a ball down an incline and having it collide into a cup — the concepts of mechanical energy, work and power, momentum, and friction are all demonstrated. During the activity, students take measurements and use equations that describe these energy of motion concepts to calculate unknown variables and review the relationships between these concepts.

Light-rail trains are a modern form of public transportation powered by overhead electrical lines that travel along a dedicated pathway of steel rails. To design these trains to be quiet, efficient and safe, engineers considered all of the energy of motion concepts: the work required to convert the mechanical energy when the train went from a stopped position to forward/backward motion, how much momentum the train acquires between stations, and the power required to overcome the friction between the train's wheels and the effects of drag.

Learning Objectives
Materials
Introduction/Motivation
Procedure
Attachments
Troubleshooting Tips
Assessment
Extensions
Activity Scaling

Grade Level: 10 (9-11)	Group Size: 3
Time Required: 60 minutes	Activity Dependency : None
Expendable Cost Per Group : US$ 7
Keywords: friction, kinetic energy, Joule, mechanical energy, momentum, potential energy, power, work

Reviews: Read Reviews \| Be the First to Write a Review

Colorado Math
- 1. model real-world phenomena (for example, distanceversus- time relationships, compound interest, amortization tables, mortality rates) using functions, equations, inequalities, and matrices; (Grades 9 - 12) [2005]
- 2. select and use appropriate algorithms for computing with real numbers in problem-solving situations and determine whether the results are reasonable; and (Grades 9 - 12) [2005]
- 1. demonstrate meanings for real numbers, absolute value, and scientific notation using physical materials and technology in problem-solving situations; (Grades 9 - 12) [2005]
- 2. select and use appropriate techniques and tools to measure quantities in order to achieve specified degrees of precision, accuracy, and error (or tolerance) of measurements; and (Grades 9 - 12) [2005]
Colorado Science
- Standard 1: Students understand the processes of scientific investigation and design, conduct, communicate about, and evaluate such investigations. (Grades 0 - 12) [1995]
- Standard 6: Students understand that science involves a particular way of knowing and understand common connections among scientific disciplines. (Grades 0 - 12) [1995]
- 2.2 Students know that energy appears in different forms, and can move (be transferred) and change (be transformed). (Grades 0 - 12) [1995]
- 2.3 Students understand that interactions can produce changes in a system, although the total quantities of matter and energy remain unchanged. (Grades 0 - 12) [1995]

After this activity, students should be able to:

Identify components of mechanical energy, work and power, momentum and friction and how they interrelate.
Construct a model to demonstrate potential and kinetic energy, work, power, momentum and friction.
Understand that energy, work and power, momentum and friction can be described by equations.
Use multiple equations to solve for unknown variables.
Calculate the amount of mechanical energy, work and power, momentum and friction in a system.

Before the Activity

Gather materials, including a copy of the Ramp and Review Worksheet for each group
You may want to set up a demo test station to help students visualize how the pieces go together.

With the Students

Pass out the materials to groups. (Note: Teams of two or four also work.)
Tape two dowel rods to each edge (of the same side) of a yardstick, approximately 1-inch apart from each other. This serves as a track for a golf ball to roll down.
Prop the yardstick against a wall or desk or rest upon a large stack of books to create a slope for the ball to roll down.
Place the cup at the end of the yardstick, and tape two dowel rods onto the table the width of the widest part of the cup. This serves as a track to ensure the cup travels in a straight path.
Place a crushed paper towel or 3-4 tissues inside the bottom of the cup to absorb the impact of the ball and help keep the ball in the cup.
Place the cup at the end of the yardstick ramp to catch the ball at the end of the incline.
Record the mass of the ball and cup, as well as the height of the ramp on your Ramp and Review Worksheet.
Place the ball at the top of the ramp, and let it go! 9. Measure the distance the cup travels at the end of the ramp. Repeat this step three times and record the average value.
Complete the Calculations and Results section of the worksheet.
Keeping in mind your results complete the Further Learning section of the worksheet.

In this illustration, a golf ball is placed at the top of an angled yardstick with rails on the sides to guide it as it rolls down the ramp. A cup is placed at the bottom of the yardstick to catch the ball. Rails are also used to guide the cup as it slides away from the bottom of the yardstick due to the force of the rolling ball.

Figure 1. The height, h, is the vertical distance from the ground to the top of the angled yardstick/ramp surface. The distance, d, is the horizontal distance from the bottom of the ramp to the point where the cup containing the ball comes to a rest.
click for copyright

If the ball falls out of the cup,

Adjust the slide rails so that the cup can not turn while sliding.
Make sure to place the cup on a smooth surface and not on carpet.
If the yardstick is angled too high or too low, the cup will not slide as well as it could. Adjust the yardstick to approximately a 30˚-40˚ angle.

Make sure the students are consistent in their measurements; e.g., when measuring how far the cup slid, they should measure from the front of the cup because the front of the cup started at the zero meter mark.

Pre-Activity Assessment

Brainstorming: Have the students engage in open discussion. Remind students that no idea or suggestion is "silly." All ideas should be respectfully heard. Ask the students to think of situations an engineer faces that involve a combination of mechanical energy, momentum, collisions, work and power, and friction. (Example answer: Designing a slide: potential energy turns into kinetic energy; friction from sliding: as you gain velocity, you gain momentum.)

Activity Embedded Assessment

Worksheet: Have the students record measurements and follow along with the activity on their Ramp and Review Worksheet. Encourage students to compare answers from the Further Learning section.

Hypothesize: Ask each group what would happen to the coefficient of friction if a heavier glass cup was used instead of a lightweight cup. (Answer: The coefficient of friction would be the same; however, the frictional force would increase.) Ask what would happen to the coefficient of friction if the surface was changed to ice. (Answer: The coefficient would decrease because there is less frictional force on ice.)

Post-Activity Assessment

Worksheet Discussion: Review and discuss worksheet answers from the Further Learning section with the entire class. Use the answers to gauge students' mastery of the subject.

Discussion Questions: As a group, ask the following questions. Have students raise their hand to answer. Write answers on the chalk/white board.

Why is the work expressed as a negative value? (Answer: Work is defined as "force acting over a distance." When the force and distance traveled are in the same direction, the value of work is positive. However, in this case of friction, the force is acting in the opposite direction of the sliding cup; hence, a negative value of work.)
How did the friction, momentum, kinetic and potential energy, and work and power all come together to make the cup move? How does this relate to activities you do every day? (Answer: To make the cup move, first we needed to build up momentum. This was done by giving the ball potential energy and converting it into kinetic energy. When the ball reached the bottom of the track, it collided with the cup and conserved momentum. Once the cup started sliding, friction came into play to bring the cup to a stop. The power of friction was related to how fast the cup stopped. This is very similar to riding down a hill with your scooter and braking to a stop.)

There is another form of mechanical energy called rotational energy that has not been discussed in this unit. In actuality, as the ball rolls down the incline, some of the potential energy is turned into rotational energy, while the rest is turned into kinetic energy. This decreases the ball's velocity as it rolls down the incline and makes our calculated value of velocity slightly higher than it really is. Have your students search the Internet to find out more about rotational energy and why it causes certain objects to roll slower down an incline.

Integrated Teaching and Learning Program, College of Engineering, University of Colorado at Boulder Chris Yakacki, Malinda Schaefer Zarske, Denise Carlson, Ben Sprague, Janet Yowell © 2007 by Regents of the University of Colorado. The contents of this digital library curriculum were developed under a grant from the Fund for the Improvement of Postsecondary Education (FIPSE), U.S. Department of Education and National Science Foundation GK-12 grant no. 0226322. However, these contents do not necessarily represent the policies of the Department of Education or National Science Foundation, and you should not assume endorsement by the federal government.

Last Modified: May 18, 2007