Learning standards covered by this activity:
Major Understanding
- 4.1a All energy transfers are governed by the law of conservation of energy.
- 4.1c Potential energy is the energy an object possesses by virtue of its position or condition. Types of potential energy include gravitational and elastic.
- 4.1d Kinetic energy is the energy an object possesses by virtue of its motion.
- 4.1e In an ideal mechanical system, the sum of the macroscopic kinetic and potential energies (mechanical energy) is constant.
- 4.1f In a non-ideal mechanical system, as mechanical energy decreases there is a corresponding increase in other energies such as internal energy.
- 4.1g When work is done on or by a system, there is a change in the total energy of the system.
Process Skill
- 4.1 i Describe and explain the exchange among potential energy, kinetic energy, and internal energy for simple mechanical systems, such as a pendulum, a roller coaster, a spring, a freely falling object
The above learning standards were taken from the Core Curriculum Physical Setting/Physics, The University of the State of New York, The State Education Department.
Materials
- Pipe covering insulation, 2 tubes per group. Make sure the inside diameter of the insulation is big enough for your marbles to fit easily in. This is about 1 ½” to 2 ½” in diameter
- Marbles (four per group)
- Masking tape (a roll per group)
Procedure
- Before class cut each tube in half the long way. (One end us usually cut already, you just need to use a box knife to slice the other end.
- You should get a semi-circle shaped tube as shown below.
- Have students work in groups of three or four and give them at least an hour and a half to complete their roller coaster.
- Allow students to masking tape a roller coaster to drop the marble down. Increase the difficulty by having the students make a mandatory loop-the-loop or corkscrew, or a set number of hills.
Student Analysis
This activity is a fun and creative way to get students thinking about potential and kinetic energy. You can ask the students the following questions or have students write answers to the following questions using vocabulary used in class.
- What difficulties did you encounter building your roller coaster?
Answer: varies - Was it possible to make the second hill taller than the first hill? What would you need to do in order to make this work?
Answer: If the student is dropping the marble then the second hill must be short, if the student is giving the marble speed while dropping it, then it would be possible to make a higher second hill. - As you pick up the marble from the ground and placing to the top of your roller coaster you are increasing the marble’s what by doing work on it?
Answer: Potential energy - Describe how the potential energy and kinetic energy of the roller coaster changes throughout the roller coaster’s path.
Answer: Potential energy decreased going down hills and when the marble went up a hill or up a loop-the-loop, then the potential energy increased. The Kinetic energy increased as the marble got closer to the ground. - Was energy conserved during the ride on the roller coaster? Give evidence to support your answer.
Answer: Some energy was lost due to friction and rotational forces (the students might not know about rotational forces though). Sometimes the marble didn’t make it over a second hill even if it was lower than the first hill because it lost too much energy along the way.
Reinforcement Activities
Have students explore circular motion as well by discussing how the marble is able to make it through the loop-the-loop. You can have students study the effect of dropping the marble from different heights to make it around a loop-the-loop with several different products offered by Cenco Physics listed below.
Have students investigate conservation of energy with the discrepant event set up by Potential/Kinetic Energy Tracks, yes it is true that if energy is conserved, two objects falling the same vertical height will have the same final speed, but does the speed need to be the same the while the objects are falling? Use this device to show students that final speed is not the same as average speed.
