What's the word?
The energy an object has because it is moving.
What is kinetic energy?
In which phase do molecules mainly move in place?
What happens to the molecules' freedom of movement during a phase change?
It changes
This word means the relative size of things.
What is scale?
A statement that can be supported or challenged with evidence.
What is a claim?
The way molecules in a substance move around relative to each other.
What is freedom of movement?
Why can a liquid flow?
Its molecules have enough freedom of movement to move around each other.
A solid is heated until it becomes a liquid. What happens to the molecules' kinetic energy?
Their kinetic energy increases.
You can observe an ice cube melting with your eyes. Is this an observation at the macroscale or molecular scale?
What is the macroscale?
Data or observations used to support a claim.
What is evidence?
The pull between molecules that keeps them attracted to one another.
What is molecular attraction?
Why doesn't gas have a visible shape?
Its molecules have a lot of freedom of movement and can move away from one another.
A liquid becomes a solid when energy is transferred away from it. What happens to the molecules?
They lose kinetic energy, so molecular attraction pulls them closer together.
Can you directly see individual molecules with your naked eye?
No. Molecules exist at the molecular scale, which cannot be observed with the naked eye.
A student says, "The water became a gas because its molecules gained kinetic energy." Is this a claim, evidence, or reasoning?
What is a claim?
A noticeably different form or state of the same substance, such as solid, liquid, or gas.
What is a phase?
When energy is transferred to a substance, what happens to the molecules' kinetic energy and freedom of movement?
Their kinetic energy increases, which can increase their freedom of movement.
A substance is heated. Its molecules gain enough kinetic energy to overcome the attraction between them. What happens?
A phase change occurs because the molecules gain more freedom of movement.
A student observes water changing from a liquid to a gas. What molecular-scale change could explain this macroscale observation?
The molecules gain kinetic energy and freedom of movement, allowing them to move farther apart.
A student records that the temperature of water increased from 20°C to 80°C. Is this a claim, evidence, or reasoning?
What is evidence?
A student says, "Temperature is the amount of heat in a substance." What vocabulary word could you use to refute this claim, and what does temperature actually measure?
What is kinetic energy? Temperature measures the average kinetic energy of the molecules in a substance.
Explain why a solid and a gas made of the same substance behave differently even though their molecules are made of the same substance.
Their molecules have different amounts of kinetic energy and freedom of movement. In a solid, molecules mainly move in place. In a gas, molecules can move much farther apart.
A student says, "When water freezes, its molecules stop moving." Refute the claim.
Molecules are ALWAYS in motion. They lose kinetic energy and have less freedom of movement, but they still move in place.
Explain how an observation at the macroscale can be explained by something happening at the molecular scale. Use at least 3 vocabulary words.
A visible change, such as melting, can be explained by molecules gaining kinetic energy and changing their freedom of movement. The molecular change explains the macroscale change we observe.
A student says: "The temperature increased. Since temperature measures average kinetic energy, the molecules gained kinetic energy. This allowed them to move more freely."
What part of a CER is this, and why?
What is reasoning? It explains how the evidence connects to the claim using scientific concepts.