Choose two or three activities for a lesson.
Forms of energy that can be covered: kinetic (motion, light, sound, thermal, electrical) and stored (gravitational, chemical, elastic, nuclear).
Either at the start of the lesson, or after an activity or two once students have experimented with energy types and conversion, start a class discussion, or ask each table group to discuss "What is energy?". Ask them to come up with an explanation of what energy actually is (a challenge!)
(The classic description: "Energy is something that can do work", but this is not so helpful for students. A more understandable sentence is: "Energy is something that can make things happen", or "Energy is something carried by an object that lets it move or change in other ways", or "Energy brings about changes in matter". See the photo for ideas that students came up with.
Pick activities from these for a lesson:
Sit in a circle and throw a bean bag to each other. Use the bean bag as a discussion tool: the student holding the bean bag can speak.
The discussion can be specifically about motion (kinetic) energy - the bean bag has motion energy as it is moving. Motion energy is the energy in a moving object. Chemical energy in our hands is converted to motion energy.
The bean bag can be used as a tool to discuss what energy is, either at the start or end of the lesson.
Energy input and output in devices activity, to explore different kinds of energy transformation in familiar household devices. Include a discussion of how electrical energy is produced from fossil fuels and renewable resources.
Make the jumping stick toy, as an example of transfer between elastic potential energy and motion energy.
Roller coaster also rich with energy transformations: gravitational potential, motion, sound and heat. (Enough for a whole lesson.)
Heat convection demonstration to demonstrate a form of heat energy.
Follow with candle heat pinwheel - using heat energy to make something move. The heat energy is transformed into motion energy.
Pinwheel for younger grades who can't use candles to see transfer of motion energy.
Candle chemistry: Chemical energy contained in the candle wax (the energy holding the particles of the wax together) transforms to heat and light energy energy during combustion.
Set off a baking soda and vinegar rocket, showing chemical energy to motion and potential energy.