Module 6: Conservation of Energy and Momentum (17 Days)
This unit begins with an overview of energy transformations. Students list quantities that are conserved in nature and examine the energy transformations.
Students then investigate gravitational potential energy through an excellent simulation. The work-energy theorem is presented in detail.
Students will use the mouse trap car to struggle with practical energy transformations and research an energy topic of interest to society.
The unit continues with an exposure to a wide variety of collision events. These are classified as mostly elastic or mostly inelastic. The concepts of impulse and momentum conservation are introduced.
Students are assigned a research project to investigate the use of these principles in safety devices for automobiles and sporting equipment. Student groups will give presentations based upon that research.
Where does the energy come from that powers the machines around us?
Where does energy go?
Will we ever run out of energy as a society?
Is it possible to have clean energy?
Rube Goldberg Machine
The following video has multiple energy conversions presented in an entertaining music video.
Knowledge & Skills
The student knows that changes occur within a physical system and applies the laws of conservation of energy and momentum.
The student is expected to investigate and calculate quantities using the work-energy theorem in various situations. (Readiness Standard)
The student is expected to investigate examples of kinetic and potential energy and their transformations (Readiness Standard)
The student is expected to calculate the mechanical energy of, power generated within, impulse applied to, and momentum of a physical system. (Readiness Standard)
The student is expected to demonstrate and apply the laws of conservation of energy and conservation of momentum in one dimension. (Readiness Standard)
The work-energy theorem follows directly from Newton’s 2nd law and states that the net work done on a mass is equal to the change in kinetic energy of that mass.
Work and the various forms of energy have specific definitions in physics, which are used to calculate the values of these quantities.
Power is the rate at which energy is used or transformed.
When two objects collide over a brief period of time, the total momentum of the two objects before the collision is equal to the total momentum after the collision. (Total momentum is the vector sum of the momentum of the two objects.)
In addition to momentum being conserved in a collision, the mechanical energy may also be conserved. Those collisions are referred to as elastic collisions, and more information about the collision may be determined.
Students may think momentum is the same as force.
Students may think momentum and kinetic energy are the same.
Momentum – product of the mass and velocity of an object
Conservation of energy – the fundamental principle of physics that the total energy of an isolated system is constant, despite internal changes
Kinetic energy – the mechanical energy that a body has by virtue of its motion
Potential energy – energy related to the position of an object
Mechanical energy – energy due to the movement of an object
Impulse – the quantity of force and time applied in a situation
Work-energy theorem – shows the relationship between work and energy
Power – rate at which work is done
Research and develop a written report on energy conservation, efficiency, and energy conversions in a small appliance.
Design and perform a laboratory investigation demonstrating how potential energy is transformed into kinetic energy.
Create a demonstration that will help to explain how bungee jumping can demonstrate elastic and inelastic collisions using the concept of impulse and momentum transfer.
Demonstrate the ability to use the momentum impulse concepts to analyze car accidents or sporting activities (e.g., baseball, golf, tennis) in an oral presentation to the class.
This module will have the stated performance indicators as well as the unit assessment and one exam.