State that energy may be stored as kinetic, gravitational potential, chemical, elastic (strain), nuclear, electrostatic and internal (thermal)

1.7.1 Energy

Energy is the ability to do work. Think of it as a “fuel” that powers everything around us. In physics we classify stored energy into several main types. Below you’ll find a quick guide to each, with everyday examples and a handy summary table.

Kinetic Energy

Energy that a body possesses because of its motion. The faster an object moves, the more kinetic energy it has.

• A ball rolling down a hill: \$\\frac{1}{2}mv^2\$.
• 🚴‍♂️ A cyclist pedalling at 15 m s⁻¹.
• ⚽ A football kicked into the air.

Gravitational Potential Energy

Energy stored because of an object’s position in a gravitational field. The higher the object, the more energy it holds.

• Climbing a ladder: \$mgh\$.
• 🏔️ A rock at the top of a cliff.
• 📦 A book on a shelf.

Chemical Energy

Energy stored in the bonds between atoms and molecules. It’s released when bonds are broken or formed.

• 🧪 Burning a candle.
• 🍎 Eating fruit – the sugar is converted to energy.
• 🚗 Fuel in a car’s tank.

Elastic (Strain) Energy

Energy stored when a material is stretched or compressed. Think of a rubber band or a spring.

• 🔗 A stretched rubber band.
• ⚙️ A compressed spring in a toy car.
• 🧱 A bent metal beam.

Nuclear Energy

Energy released when the nucleus of an atom changes. It’s the power behind the sun and nuclear power plants.

• ☀️ Fusion in the sun.
• 🔬 Radioactive decay in a medical X‑ray machine.
• 🛢️ Nuclear reactors producing electricity.

Electrostatic Energy

Energy stored in the electric field between charged objects. It’s the force that makes a balloon stick to a wall after rubbing it on hair.

• ⚡ Static electricity from a rubbed balloon.
• 🔌 The charge stored in a capacitor.
• 🧲 The attraction between magnets (though technically magnetic, it’s related to electric charges).

Internal (Thermal) Energy

Energy associated with the random motion of particles inside a substance. It’s what we feel as heat.

• 🔥 A hot cup of tea.
• 🌡️ Warm air rising from a radiator.
• 🧊 Ice melting as it absorbs heat.

Summary Table