Systems and Energy Transfers

• Physics
• Lower Secondary (Key Stage 3)

Systems and Energy Transfers

Learning Objectives

• Understand what a system is and the concept of a closed system
• Identify different types of energy stores
• Comprehend how energy is transferred between stores and surroundings

What do you already know about energy transfers?

Definition of a System

• A system is a group of objects where energy changes occur
• Energy can be stored in various forms such as kinetic, gravitational potential, thermal, etc.

Concept of a Closed System

• A closed system is one where no energy can escape to or enter from the surroundings
• Total energy of a closed system remains constant

Types of Energy Stores

• Kinetic
• Gravitational potential
• Elastic potential
• Thermal
• Chemical
• Nuclear
• Magnetic
• Electrostatic

What type of energy store is present in a stretched rubber band?

1. Sound energy
2. Light energy
3. Magnetic energy
4. Elastic potential energy

What is the energy store when a person climbs up a ladder?

1. Kinetic energy
2. Nuclear energy
3. Gravitational potential energy
4. Thermal energy

Which of the following is an example of a kinetic energy store?

1. Sleeping person
2. Stationary rock
3. Moving car
4. Still water

Which energy store is involved when a battery is charged?

1. Nuclear energy
2. Gravitational energy
3. Chemical energy
4. Elastic energy

What is the name of the energy store when a car is moving?

1. Thermal energy
2. Potential energy
3. Chemical energy
4. Kinetic energy

Which of the following is an example of a gravitational potential energy store?

1. Blown balloon
2. Melting ice cube
3. Growing plant
4. Elevated water

Which of the following is an example of a thermal energy store?

1. A candle
2. Charging phone
3. Running car engine
4. Boiling water

In what energy store is the food we eat transformed into?

1. Nuclear energy
2. Electrical energy
3. Kinetic energy
4. Chemical energy

Which of the following is an example of an elastic potential energy store?

1. Glass bottle
2. Metal spoon
3. Stretched rubber band
4. Magnet

Which of the following is an example of a chemical energy store?

1. Wind turbines
2. Solar panels
3. Nuclear power
4. Batteries

Modes of Energy Transfers

• Heating
• Waves
• Electricity
• Forces

Which energy transfer occurs when a wind turbine converts wind into electricity?

1. Heating
2. Mechanical work (Forces)
3. Electrical current
4. Waves

What type of energy transfer is involved when a battery powers an electronic device?

1. Electrical current
2. Mechanical work (Forces)
3. Heating
4. Waves

What form of energy transfer occurs when a kettle heats water?

1. Mechanical work (forces)
2. Waves
3. Electrical current
4. Heating

Which type of energy transfer takes place when a light bulb emits light?

1. Heating
2. Waves
3. Mechanical work (forces)
4. Electrical current

Summary

• A system is a group of objects where energy changes occur
• A closed system does not allow energy to escape or enter
• Energy can be stored in various forms
• Energy can be transferred through heating, waves, electricity, and forces

Write down 3 things you learned in this lesson.

Have students enter three things they learned in this lesson. With this they can indicate their own learning efficiency of this lesson.

Write down 2 things you want to know more about.

Here, students enter two things they would like to know more about. This not only increases involvement, but also gives them more ownership.

Ask 1 question about something you haven't quite understood yet.

The students indicate here (in question form) with which part of the material they still have difficulty. For the teacher, this not only provides insight into the extent to which the students understand/master the material, but also a good starting point for the next lesson.