Lesson 31: Matter vs Energy
Matter has mass and occupies space; energy can be stored and transferred by objects and systems. Motion, light, and electrical circuits provide examples of how material changes and energy transfers occur together.
Key Ideas
- Matter has mass and takes up space. Air, water, and rocks are all matter.
- Energy can be stored and transferred. A moving ball has energy, and a battery stores energy.
- Energy transfers can make matter move, warm up, or change. Sunlight can warm a rock, and a push can start a ball rolling.
- Light carries energy across empty space. Sunlight reaches Earth even though space has very little matter.
- Matter and energy help us describe different parts of the same event. A rolling ball is matter, and its movement has energy.
Vocabulary
- Matter: Anything that has mass and takes up space. Solids, liquids, and gases are all matter.
- Energy: The ability to cause changes, such as movement or warming. Energy can be stored and transferred.
- Mass: The amount of matter in an object. Mass does not change based on gravity.
- Occupies Space: Takes up room. A balloon gets bigger when air fills it.
- Particulate Nature: The idea that matter is made of tiny particles, such as atoms and molecules.
- Kinetic / Potential Energy: Kinetic: energy of motion. Potential: energy stored through position, arrangement, or condition.
Discussion Questions
- What changes in a flashlight when it is switched on? Which materials remain, and where is energy transferred?
- What changes when a ball is thrown or a spring is stretched? Describe both the material and the energy.
- A shadow is a region receiving less light. Is a shadow an added substance? What evidence supports your explanation?
Hands-On Activity: Does Air Have Mass?
Supply List
- A balloon and a kitchen scale
- A notebook and pencil
Instructions
- Place the empty, flat balloon on the scale and record the reading.
- Blow up the balloon, tie it off, and weigh it again.
- Did the scale reading change? Is the change large enough for this scale to measure? The balloon also takes up more space when inflated, which can affect a careful measurement.
- Describe the matter added and explain why a balance reading alone does not measure the energy used to inflate it.
Hands-On Activity: Where Does Light Energy Go?
Supply List
- A flashlight
- A jar or box with a lid
- A notebook and pencil
Instructions
- Shine the flashlight into the open jar or box for a few seconds.
- Quickly close the lid while the flashlight is still on, then turn the flashlight off.
- Open the lid. Is there any light visible inside?
- Discuss where the light energy went. Does darkness mean that energy was destroyed? This observation is not a universal test of whether energy can be stored.