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
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.
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.
Hydrogen Fuel Cell	★★★	★★☆	★★☆	A hydrogen fuel cell kit demonstrates how water can be split into hydrogen and oxygen using electrolysis, and how the gases can later be recombined in the fuel cell to generate electricity that powers a small device such as a motor or light.
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.
Nichrome Wire Kettle	★★☆	★★☆	★★☆	A coil of nichrome wire is used to heat water in a beaker by converting electrical energy into heat energy through resistance, demonstrating the principle behind an electric kettle.
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.
The Spinning Can	★☆☆	★★☆	★☆☆	A can with small angled holes near its base will spin when filled with water and suspended.
Balloon Powered Car	★☆☆	★☆☆	★☆☆	Students construct a simple car powered by the air escaping from a balloon. The activity demonstrates Newton’s laws of motion and the conversion of potential energy stored in the inflated balloon into kinetic energy as the car moves forward.
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.
Crumple Zones Egg Car	★☆☆	★☆☆	★☆☆	This demonstration models how crumple zones in cars protect passengers during a collision. A small car carrying an egg is rolled down a ramp and crashed. Without protection, the egg breaks, but when a sponge or other soft material is added to the front, it absorbs impact energy, protecting the egg.
Drinking Bird	★★★	★☆☆	★☆☆	The drinking bird is a classic science demonstration that appears to move endlessly by dipping its beak into a glass of water and bobbing back up again. In reality, it operates through heat transfer and changes in vapor pressure, showing the conversion of thermal energy into mechanical motion.
Efficiency of Bouncing Balls	★☆☆	★☆☆	★☆☆	Different types of balls are dropped from a set height, and the height of their bounce is measured to determine their efficiency in conserving energy during impact.
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.
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.
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.
Marshmallow Catapult	★☆☆	★☆☆	★☆☆	Build a simple catapult using ice cream sticks, rubber bands, and a spoon to launch soft objects like marshmallows. This activity demonstrates how elastic potential energy can be converted into kinetic energy and how energy transfer creates motion.
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.
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.
Potato / Lemon Battery	★★☆	★☆☆	★☆☆	By inserting copper and zinc electrodes into a potato, you can create a simple battery.
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.
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.
Rubber Band Powered Car	★☆☆	★☆☆	★☆☆	A simple car is built from cardboard, straws, wooden skewers, CDs, and a rubber band. Winding the rubber band stores elastic potential energy, which is released to spin the axle and propel the car forward.
Spinning Convection Snake	★☆☆	★☆☆	★★☆	A paper snake cut into a spiral shape spins when held over a heat source, demonstrating how convection currents move air and transfer heat.
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.
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.

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