Watch a pendulum swing back and forth. At the highest points, it pauses briefly. At the lowest point, it moves fastest.
🤔 Where does the energy go? Why does it slow down at the ends and speed up at the bottom?
Think about: At the highest points, energy is stored as potential energy (height). At the bottom, it's all converted to kinetic energy (motion). Energy transforms back and forth!
PotentialKineticThermal
Observation 2: Dropping a Ball
Drop a ball from height. Watch it bounce. Each bounce is lower than the last. Eventually it stops.
🤔 Where does the energy go? Why doesn't it bounce back to the same height?
Think about: Some energy converts to heat (thermal energy) and sound on each bounce. Energy is conserved, but some becomes less useful forms!
PotentialKinetic
Observation 3: Roller Coaster Hills
On a roller coaster, the first hill is always the tallest. Later hills are smaller.
🤔 Why can't later hills be taller than the first? What would happen if they tried?
Think about: The first hill gives the coaster its total energy. Without adding energy, it can never go higher than where it started. Energy conservation!
ChemicalThermalKinetic
Observation 4: Eating Food
After eating a meal, you have energy to run, think, and stay warm. Food contains "calories" - a unit of energy.
🤔 What happens to the chemical energy in food? Where does it all go?
Think about: Chemical energy converts to kinetic energy (movement), thermal energy (body heat), and is stored as potential energy (fat). Your body is an energy conversion machine!
Elastic PotentialKinetic
Observation 5: Stretching a Rubber Band
Stretch a rubber band and hold it. When you release it, it flies across the room.
🤔 Where does the energy come from that makes it fly? What happens if you stretch it more?
Think about: Stretching stores elastic potential energy. More stretch = more stored energy = faster flight! This is like a spring.
Made your observations? Now let's understand the science of energy.