Particles
What are the tiny building blocks of all matter?
Atoms
Name the three main states of matter.
Solid, liquid, gas
What is thermal energy?
The total energy of motion of particles in a substance
What do we call the change from solid to liquid?
Why does water expand when it freezes?
The particles arrange in a crystal structure that takes up more space
According to the particle model, how do particles move in a solid?
They vibrate in fixed positions
Which state of matter has a definite shape and volume?
Solid
How is temperature related to the motion of particles?
Higher temperature = faster particle motion
What is the opposite of condensation?
Evaporation
Why do we feel cooler when sweat evaporates from our skin?
Evaporation uses heat energy from our body, cooling us
What is the difference between an atom and a molecule?
An atom is a single particle of an element; a molecule is two or more atoms bonded together
How do the particles in a liquid behave differently than in a gas?
Liquid particles slide past each other but stay close; gas particles move freely and spread apart
What’s the difference between heat and temperature?
Heat is energy transfer; temperature is the average kinetic energy of particles
Why does melting ice not increase in temperature until all the ice has melted?
The heat energy is used to break particle bonds, not raise temperature
Why does popcorn “pop” when heated?
Water inside the kernels turns to steam, building pressure until the kernel bursts
Why do particles in gases have more freedom to move than particles in solids?
Because they are farther apart and not held tightly together
Plasma is sometimes called the “fourth state of matter.” What makes plasma different from gases?
Plasma has charged particles (ions and electrons)
Why does a metal spoon feel colder than a wooden spoon, even if they are at the same temperature?
Metal conducts heat away from your hand faster than wood
What is sublimation? Give one example.
Solid turning directly into gas; e.g. dry ice (solid CO₂)
How do thermal energy and particle motion explain why hot air balloons rise?
Heated air particles move faster and spread apart, making the air less dense than the cooler outside air
Explain how the particle model helps us understand why gases can be compressed but solids cannot.
Gas particles are spread out , so they can be pushed closer; solid particles are tightly packed
Why do scientists consider Bose-Einstein condensates a state of matter, and how do the particles behave in this state?
At very low temperatures, particles group together and act as a single "super-particle"
Explain why adding the same amount of heat to two substances can cause different temperature changes.
Different substances have different specific heats (they absorb energy differently)
Using the particle model, explain why evaporation can happen at temperatures below boiling.
Some surface particles have enough energy to escape into the air even before boiling point
Engineers design spacesuits for astronauts with layers of insulation. Using thermal energy and states of matter, explain why insulation is necessary in space.
Insulation reduces heat transfer (extreme hot and cold) since space has no air to regulate temperature