Energy: Forms and Transfer — Answer Key
Part A: Multiple Choice
Circle the best answer for each question.
1. A child pedals a bicycle up a hill. Which energy chain matches what happens?
A) Light to chemical to motion to potential energy
B) Chemical (in food) to motion (pedaling) to kinetic and potential energy of the bike
C) Sound to electrical to potential energy
D) Heat to chemical to light energy
In Grade 4 Science, food gives chemical energy that the body turns into motion, which becomes kinetic and potential energy as the bike climbs.
2. Why does a desk lamp feel warm after being on for a while, even though it is meant to give off light?
A) Some electrical energy is changed into heat energy as well as light
B) All electrical energy becomes only sound energy
C) The lamp creates new energy out of nothing
D) The lamp turns light energy into chemical energy
Grade 4 learners study how lamps change electrical energy into light, but some always becomes heat energy too.
3. Which statement best matches the idea of conservation of energy in Grade 4 Science?
A) Energy disappears when a battery runs out
B) Energy can only be created by big machines
C) Energy is never made or destroyed; it only changes form
D) Energy only exists in moving objects
Grade 4 Science teaches that energy is conserved, meaning the total amount stays the same while it changes form.
4. An electric oven cooks a pizza. Which best describes the main energy transfer to the pizza?
A) The pizza loses chemical energy to the air
B) Electrical energy in the oven becomes heat energy that transfers to the pizza
C) Light energy from the pizza becomes electrical energy
D) Sound energy from the oven becomes chemical energy in the pizza
In Grade 4 Science, an electric oven changes electrical energy into heat, which is then transferred to the food and cooks it.
Part B: Fill in the Blank
Write the correct answer on each line.
1. When a bouncing ball loses height with each bounce, energy is being transferred to the ground and the air, mostly as heat energy.
Grade 4 students learn that bouncing balls lose kinetic energy mainly to heat and a little to sound.
2. A guitar string changes motion energy into sound energy that travels to your ears.
In Grade 4 Science, vibrating guitar strings transfer motion energy into sound waves that move through the air.
3. In a complete energy chain, the total amount of energy at the start equals the total amount at the end.
Grade 4 learners apply conservation of energy by checking that energy in equals energy out for each chain they study.
4. A hand-cranked flashlight first turns motion energy into electrical energy, then into light energy.
In Grade 4 Science, hand-crank flashlights show a clear chain from motion to electrical to light energy.
5. Even though useful energy seems to disappear, it has often turned into heat energy that spreads out into the surroundings.
Grade 4 students learn that lost energy is usually thermal energy that has spread out and is hard to recover.