Energy: Forms and Transfer — Answer Key
Part A: Multiple Choice
Circle the best answer for each question.
1. Why do scientists say energy is conserved in every system?
A) It disappears when used
B) It only changes form, never created or destroyed
C) It doubles each time it transfers
D) It can be made from nothing
Grade 4 students learn that energy is conserved: the total amount stays the same. Energy only transforms between forms; it is never destroyed or created.
2. What is the original source of the energy in the food you eat for lunch?
A) Wind
B) The sun
C) Ocean tides
D) Rocks underground
Grade 4 science traces food energy back to plants, which use sunlight to grow. The sun is the original source for almost all food chains on Earth.
3. A car burns gasoline to move. Where did the energy in gasoline first come from millions of years ago?
A) Lightning storms
B) Sunlight captured by ancient plants
C) Volcanoes
D) Earth's core
Grade 4 lessons explain that gasoline comes from ancient plants that captured sunlight. Even fossil fuel energy chains start with the sun.
4. Wind turbines spin to make electricity. What is the original source of wind energy?
A) Earth's gravity
B) The sun heats air unevenly
C) Ocean salt
D) Underground water
Grade 4 students learn that wind comes from the sun heating Earth unevenly, causing air to move. So even wind energy traces back to sunlight.
Part B: Fill in the Blank
Write the correct answer on each line.
1. The law that says energy is never created or destroyed is called the law of conservation of energy.
Grade 4 science introduces conservation of energy. This law states the total energy in a closed system stays constant through all changes.
2. Almost every energy chain on Earth begins with the sun.
Grade 4 lessons teach that the sun is the starting point for most Earth energy chains, including food, weather, fossil fuels, and wind.
3. When energy transforms, the total amount in the system stays the same.
Grade 4 students learn that the total amount of energy never changes during transformations. Forms change, but the total quantity is conserved.
4. Plants capture sunlight and store it as chemical energy in their leaves and seeds.
Grade 4 science teaches photosynthesis: plants store sunlight as chemical energy. This becomes the food energy that animals and humans eat.
5. Even though some energy turns into heat or sound, it is not lost; it is just transferred to the surroundings.
Grade 4 lessons emphasize that wasted heat or sound is still real energy. It transfers to the air and surroundings instead of being destroyed.