Lesson 20: Energy in Nature
Sunlight supplies energy to plants and most familiar food webs. This lesson follows energy through organisms and the surroundings, then compares fossil fuels with renewable energy sources.
Key Ideas
- Moving things have kinetic energy. Energy can also be stored, as in a raised rock, a stretched spring, or food.
- Energy can change form or move between things. It cannot be created from nothing or destroyed.
- Friction spreads energy into objects and their surroundings as warmth. Machines often need more energy supplied to keep running.
- Animals use chemical energy stored in food. Their cells release energy for movement, growth, and other life activities.
- Most plants use sunlight to make sugars that store energy. That energy can pass to an animal when it eats the plant.
Vocabulary
- Kinetic Energy: The energy an object has because it is moving.
- Potential Energy: Stored energy, such as in a raised object or a stretched spring.
- Chemical Energy: Energy stored in materials such as food, fuel, and batteries that can be released through chemical changes.
- Energy Transfer: Energy moving from one thing to another, such as from a warm cup to your hands.
Discussion Questions
- Where does the energy in your body come from? Can you trace it all the way back to the Sun?
- Why can't plants just make energy out of nothing? What are they actually doing with sunlight?
- Imagine there were no sunlight for a year. What do you think would happen to life on Earth?
- A plant gets eaten by a rabbit, and the rabbit gets eaten by a fox. Where did the energy that powers the fox's muscles originally come from?
- What happens to energy after an animal uses it to run, think, or move? Where does that energy go?
- Why does Earth need a constant supply of sunlight if energy can't simply be recycled forever?
- Fossil fuels contain energy from ancient living things. How is burning gasoline similar to releasing stored sunlight?
- What do solar panels, wind turbines, and hydroelectric dams have in common? How are they ultimately connected to the Sun?
- If you could invent a new way to capture energy from sunlight, wind, or water, what would it look like?
- Which seems more surprising to you: that plants can turn sunlight into stored energy, or that your body can turn food into the energy needed to think and move? Why?