Energy Demonstrations

See also: Heat

Energy is the capacity to do work and exists in many forms, including kinetic, potential, thermal, and chemical. This category introduces the principles of energy transformation, conservation, and transfer. Learning about energy provides a framework for connecting different areas of science and understanding the processes that drive the natural and technological world.

Demonstration	Materials	Difficulty	Safety	Summary
Burning Paper with Colliding Steel Balls	★★★	★☆☆	★☆☆	When two steel balls are struck together with paper between them, the collision generates enough heat to scorch and burn the paper.
Franklin’s Bells	★★★	★★☆	★★☆	A small conductive ball swings back and forth between two metal plates, alternately charging and discharging as it contacts each plate.
Giant Pendulum	★★★	★★☆	★★☆	A large pendulum suspended from the ceiling demonstrates conservation of energy by swinging out and back to its starting point near the instructor’s chin, never exceeding its original height. The dramatic demonstration shows that mechanical energy is conserved and that potential energy converts to kinetic energy and back.
Happy and Sad Balls	★★★	★☆☆	★☆☆	This demonstration compares how different materials affect energy transfer in collisions. A "happy" ball made of neoprene rubber bounces high, showing an elastic collision, while a "sad" ball made of norbornene barely bounces, showing an inelastic collision.
Stirling Engine	★★★	★★☆	★☆☆	A low temperature Stirling engine placed over a cup of hot water runs as heat flows from the water to the engine, demonstrating energy conversion from heat to mechanical motion.
Glowstick Dissection	★★☆	★★☆	★★★	This demonstration explores the chemical reaction inside glowsticks by dissecting them and using their contents to create glowing artwork. Students learn about chemiluminescence and reaction rates while experimenting with color, brightness, and duration of glow.
Lead Storage Battery	★★☆	★☆☆	★★☆	This experiment demonstrates how a lead storage battery works by constructing a simple lead-acid cell, charging it with a direct-current power supply, and then discharging it. It illustrates the reversible redox reactions that make rechargeable batteries possible.
Newton's Cradle	★★☆	★☆☆	★☆☆	A Newton’s cradle demonstrates conservation of momentum and energy through swinging metal spheres that collide in sequence. When one or more spheres are released, the same number of spheres on the opposite side swing out with nearly identical motion.
Potato / Lemon Battery	★★☆	★☆☆	★☆☆	By inserting copper and zinc electrodes into a potato, you can create a simple battery.
Rotating Chair with Dumbbells	★★☆	★☆☆	★★☆	A person seated on a rotating chair holds dumbbells with arms extended. As the person pulls the dumbbells inward, the chair spins faster, demonstrating conservation of angular momentum. Extending the arms again slows the rotation.
Three Energy Systems in the Body	★★☆	★☆☆	★★☆	This lesson explores how the body produces energy through three different systems - the ATP-PC system, the glycolytic system, and the oxidative system. Students connect these systems to physical activities such as sprinting, weightlifting, and endurance exercise.
Kettle Power	★☆☆	★☆☆	★★☆	Two electric kettles of different power ratings (e.g., 1 kW and 3 kW) are compared to show how electrical power relates to the rate of energy transfer. The demonstration illustrates that the higher-power kettle boils water faster and reinforces the relationship P = IV.
Microwaving Grapes to Create Plasma	★☆☆	★★☆	★★★	When two grapes slices are microwaved while touching, the microwave energy concentrates at their point of contact, creating an intense electric field strong enough to strip electrons from atoms. This ionizes the material and produces glowing plasma inside the microwave.
Pendulum Period Investigation	★☆☆	★☆☆	★☆☆	Students build a simple pendulum and test how string length, bob mass, and release angle affect the time for one swing. The demonstration shows that for small angles the period depends mainly on length, not mass or amplitude.
Pizza Box Solar Oven	★☆☆	★☆☆	★☆☆	This activity demonstrates how sunlight can be harnessed to cook food. A pizza box lined with foil and sealed with plastic wrap becomes a solar oven, concentrating the sun’s rays and converting them into heat energy to warm or cook food.
Rollback Can	★☆☆	★☆☆	★☆☆	A weighted rubber band is suspended inside a can. Rolling the can forward twists the band and stores elastic potential energy; when the can stops, the band unwinds and drives the can to roll back.
Stacked Ball Drop	★☆☆	★☆☆	★☆☆	A ping pong ball is dropped alone, with a golf ball, and then stacked above the golf ball to observe differences in rebound height. The demonstration shows how energy conservation and transfer limit the maximum possible bounce height.
The Spinning Can	★☆☆	★★☆	★☆☆	A can with small angled holes near its base will spin when filled with water and suspended.

Materials
★☆☆ Easy to get from supermarket or hardware store
★★☆ Available in most school laboratories or specialist stores
★★★ Requires materials not commonly found in school laboratories

Difficulty
★☆☆ Can be easily done by most teenagers
★★☆ Available in most school laboratories or specialist stores
★★★ Requires a more experienced teacher

Safety
★☆☆ Minimal safety procedures required
★★☆ Some safety precautions required to perform safely
★★★ Only to be attempted with adequate safety procedures and trained staff