# 12th Grade Work, Conservation Of Machanical Energy Lesson Plan (Physical Education)

## Topic: Work, conservation of machanical energy

### Objectives & Outcomes

• Understand the concept of conservation of mechanical energy and its practical applications.

### Content

• Mechanical energy is the energy of motion and can be represented by a vector
• The Law of Conservation of Mechanical Energy states that the total mechanical energy of a system remains constant during a closed system process if no work is done on or by the system
• Work is done when a force produces a displacement, and is measured in units of energy such as Joules (J) or KiloJoules (kJ)
• The relationships between work, energy, and displacement can be expressed mathematically as follows:

### ΔW = FΔd

• One of the practical applications of the Law of Conservation of Mechanical Energy is in the area of simple machines, where it can be used to predict the resulting displacement and/or rotational velocities of a system as a result of a given amount of applied force
• The Law of Conservation of Mechanical Energy can also be used to calculate the total mechanical energy of a system at the beginning and end of a given process in order to check for any unwanted or unbalanced losses of energy

### Assessment

• Written test or exam on the content of the lesson
• Interactive worksheets or practice problems related to the lesson
• Exam or Short Write on the practical applications of the Law of Conservation of Mechanical Energy in the area of simple machines

### Resources

• Textbook or other printed materials on the topic
• Handouts with definitions and mathematical expressions
• Calculator
• Computers with internet access for research and practice problems
• Simple machines (e.g. screwdriver, hammer, wheelbarrow)

### Warm-up

• Ask students to think about a time when they had to do work in order to achieve a goal or achieve something they wanted. Ask them to share their experiences with the class and discuss the following questions:
• What were you trying to achieve?
• What needed to be done in order to achieve the goal?
• Did you feel tired or energized at the end of the process? Why?
• How is the process of doing work similar to or different from the concept of conservation of mechanical energy?
• review any vocabulary or concepts that may be new to the students, such as energy, work, and simple machines

### Presentation

• Begin the lesson by presenting the concept of mechanical energy and its conservation in a simple and understandable way. For example, show students a box with a lid that is attached to a string and a weight at the other end of the string. Explain that when the box is opened, the weight will fall and do work by pulling down the lid of the box. Ask students to consider the following questions:
• What type of energy is involved in this process?
• How is this type of energy different from other types of energy, such as thermal energy or chemical energy?
• How can we represent the energy of motion or mechanical energy as a vector?
• How can we account for any changes in the total amount of mechanical energy in a system during a closed process, such as the one shown with the box and the weight?
• After discussing these questions, introduce the concept of the Law of Conservation of Mechanical Energy and its practical applications in the area of simple machines.

### Demonstration

• Using the box, weight, and string, demonstrate the process of doing work and conserving mechanical energy. Have students pay attention to the changes in the total amount of mechanical energy in the system during the demonstration.
• After the demonstration, ask students to think about how the concept of conservation of mechanical energy can be applied to the simple machines that they have already learned about in class. Ask them to share their thoughts with the class and discuss the following questions:
• How does the use of a simple machine change the amount of mechanical energy in a system?
• How does the conservation of mechanical energy help us understand how a simple machine works?

### Guided practice

• Divide the class into small groups and provide each group with a simple machine (e.g. a gin wheel, a screw, a lever).
• Have each group work together to come up with a scenario that demonstrates how the simple machine works and how the concept of conservation of mechanical energy applies to the scenario.
• Have each group present their scenario to the class and discuss how the concept of conservation of mechanical energy helps explain how the simple machine works.

### Independent practice

• Have students work in pairs to design and build their own simple machine. They should use the concept of conservation of mechanical energy to guide their design.
• Encourage students to be creative and think outside the box.

### Closure

• Have students share their simple machines with the class and explain how they were designed to conserve mechanical energy.
• Review the concept of conservation of mechanical energy and how it can be applied to simple machines.

### Assessment

• Observe students during the engineering challenge and provide feedback on their potential solutions.
• Have students complete a simple quiz on the concept of conservation of mechanical energy and its application to simple machines.