Maximizing Kinetic Energy: An Investigation Using Marbles and Marble Run Construction Sets
Summary
In this physics lab, students investigate what variables in the construction of a marble run affect the velocity and kinetic energy of the marble at the end of the run. They construct various runs using different combinations of tubes, slides, and ramps of different slopes, and they compare the final velocity and kinetic energy of the marble at the end of each run. Students share their data with the class and work together to identify the factors that affected final velocity. They complete a lab report summarizing their findings.
CollapseLearning Goals
Content goals:
-Projectile motion: Students will be able to calculate the velocity of a marble after collecting data on the horizontal distance traveled and the vertical distance from the table to the floor.
-Kinetic energy: Students will be able to calculate the kinetic energy of a marble after finding its velocity.
-Potential energy: Students will discover the relationship between the height of a run and kinetic energy, and they will be able to interpret this relationship in terms of potential energy.
-Forces: Students will discover the relationship between steepness of a ramp and final velocity and interpret this using a free body diagram that shows how the gravitational force on the marble varies with ramp angle.
Thinking skills and science process skills:
-Students will be able to design a data table to collect data from their experiment.
-Students will be able to design an experimental set-up to test their hypotheses about relevant factors affecting the outcome (including sufficient replication of trials).
-Students will be able to analyze their data as the experiment progresses, form new hypotheses, and change their experimental set-up to test new hypotheses.
-Students will be able to analyze aggregate data from the class and determine which variables affect the outcome of the experiment.
-Students will be able to use the following concepts to interpret their results:
*Energy is conserved but may be converted from potential to kinetic and vice versa.
*Gravitational potential energy of an object close to the surface of the Earth is proportional to the height of the object.
*The magnitude of the gravitational force acting on an object on a ramp is dependent on the angle of the ramp.
-Students will use the following vocabulary in analyzing their results:
*velocity
*projectile motion
*acceleration
*gravitational force
*kinetic energy
*potential energy
-Projectile motion: Students will be able to calculate the velocity of a marble after collecting data on the horizontal distance traveled and the vertical distance from the table to the floor.
-Kinetic energy: Students will be able to calculate the kinetic energy of a marble after finding its velocity.
-Potential energy: Students will discover the relationship between the height of a run and kinetic energy, and they will be able to interpret this relationship in terms of potential energy.
-Forces: Students will discover the relationship between steepness of a ramp and final velocity and interpret this using a free body diagram that shows how the gravitational force on the marble varies with ramp angle.
Thinking skills and science process skills:
-Students will be able to design a data table to collect data from their experiment.
-Students will be able to design an experimental set-up to test their hypotheses about relevant factors affecting the outcome (including sufficient replication of trials).
-Students will be able to analyze their data as the experiment progresses, form new hypotheses, and change their experimental set-up to test new hypotheses.
-Students will be able to analyze aggregate data from the class and determine which variables affect the outcome of the experiment.
-Students will be able to use the following concepts to interpret their results:
*Energy is conserved but may be converted from potential to kinetic and vice versa.
*Gravitational potential energy of an object close to the surface of the Earth is proportional to the height of the object.
*The magnitude of the gravitational force acting on an object on a ramp is dependent on the angle of the ramp.
-Students will use the following vocabulary in analyzing their results:
*velocity
*projectile motion
*acceleration
*gravitational force
*kinetic energy
*potential energy
Context for Use
Activity type: indoor lab
Time needed: One block period (80 minutes) for planning, carrying out the experiment, and sharing data. One block period for data analysis and discussion of relevant concepts.
Prerequisite concepts: velocity, acceleration, projectile motion, forces, free-body diagrams, kinetic energy.
Equipment: balance, marbles, wide variety of marble run construction set pieces (can be placed in a single bin for all groups to select pieces from), white paper, carbon paper, meter sticks, protractors.
Time needed: One block period (80 minutes) for planning, carrying out the experiment, and sharing data. One block period for data analysis and discussion of relevant concepts.
Prerequisite concepts: velocity, acceleration, projectile motion, forces, free-body diagrams, kinetic energy.
Equipment: balance, marbles, wide variety of marble run construction set pieces (can be placed in a single bin for all groups to select pieces from), white paper, carbon paper, meter sticks, protractors.
Description and Teaching Materials
-Organize students in groups of 3-4.
-Give each group one marble and have them find its mass on a balance.
-Explain the goal of the experiment (to figure out which factors affect the marble's velocity and kinetic energy).
-Review how to calculate velocity using projectile motion equations, provide equation for kinetic energy.
-Have students hypothesize what factors might affect the velocity of the marble.
-Show students materials they can use (marble run pieces, meter sticks, white paper, carbon paper, protractors).
-Ask students to design an experimental set-up to test their hypotheses.
-Assist students as needed with design (students may need help figuring out how to use carbon paper to record where the marble fell on the white paper).
-Have students begin the experiment and make new hypotheses to test after a few trials.
-Assist students in designing experimental set-ups to test subsequent hypotheses.
-Assist students with data analysis. Provide information about conservation of energy and gravitational potential energy. Rubric for the Marble Run Lab Report (Microsoft Word 23kB Aug3 09)
-Give each group one marble and have them find its mass on a balance.
-Explain the goal of the experiment (to figure out which factors affect the marble's velocity and kinetic energy).
-Review how to calculate velocity using projectile motion equations, provide equation for kinetic energy.
-Have students hypothesize what factors might affect the velocity of the marble.
-Show students materials they can use (marble run pieces, meter sticks, white paper, carbon paper, protractors).
-Ask students to design an experimental set-up to test their hypotheses.
-Assist students as needed with design (students may need help figuring out how to use carbon paper to record where the marble fell on the white paper).
-Have students begin the experiment and make new hypotheses to test after a few trials.
-Assist students in designing experimental set-ups to test subsequent hypotheses.
-Assist students with data analysis. Provide information about conservation of energy and gravitational potential energy. Rubric for the Marble Run Lab Report (Microsoft Word 23kB Aug3 09)
Teaching Notes and Tips
*Teachers who have access to Vernier photogates or similar tools could allow students to use them to find the final velocity, rather than calculating velocity using the projectile motion equations.
*Teachers can motivate students by framing the lab as a competition to see which group can get their marble going the fastest.
*Depending on their prior experiences with inquiry, students may need more or less support in designing the experimental set-up and deciding which data to collect. Sharing data from multiple groups can help in case a specific group did not collect data on a relevant variable (ramp angle or height).
*Teachers can motivate students by framing the lab as a competition to see which group can get their marble going the fastest.
*Depending on their prior experiences with inquiry, students may need more or less support in designing the experimental set-up and deciding which data to collect. Sharing data from multiple groups can help in case a specific group did not collect data on a relevant variable (ramp angle or height).
Assessment
Formative assessment:
-Check students' predictions and experimental designs, and ask them questions to determine whether they are thinking like scientists.
-Ask students questions about the class data and check that they are applying relevant concepts.
Summative:
-Check lab reports using the rubric provided above.
-Check students' predictions and experimental designs, and ask them questions to determine whether they are thinking like scientists.
-Ask students questions about the class data and check that they are applying relevant concepts.
Summative:
-Check lab reports using the rubric provided above.
Standards
Forces: 9P.2.2.1: Forces and inertia determine the motion of objects.
Free-body diagrams: 9P.2.2.1.1: Use vectors and free-body diagrams to describe force, position, velocity, and acceleration of objects in two-dimenstional space.
Gravitational force: 9P.2.2.1.3: Use gravitational force to explain the motion of objects near Earth and in the universe.
Conservation of Energy: 9P.2.2.2: When objects change their motion of interact with other objects in the absences of frictional forces, the total amount of mechanical energy remains constant.
Potential and Kinetic Energy: 9P.2.2.2.1: Explain and calculate the...potential energy and kinetic energy involved in objects moving under the influence of gravity and other forces.
Free-body diagrams: 9P.2.2.1.1: Use vectors and free-body diagrams to describe force, position, velocity, and acceleration of objects in two-dimenstional space.
Gravitational force: 9P.2.2.1.3: Use gravitational force to explain the motion of objects near Earth and in the universe.
Conservation of Energy: 9P.2.2.2: When objects change their motion of interact with other objects in the absences of frictional forces, the total amount of mechanical energy remains constant.
Potential and Kinetic Energy: 9P.2.2.2.1: Explain and calculate the...potential energy and kinetic energy involved in objects moving under the influence of gravity and other forces.