ScienceGrade 3

What Happens to Matter When It Is Heated or Cooled?

Heating gives matter more energy — its particles move faster.

Learning Objective

Students will learn that heating adds energy and cooling takes energy away — and that at certain temperatures matter changes state: solids melt to liquids, liquids freeze to solids, liquids evaporate to gas, and gas condenses back to liquid. (TEKS 3.6C — predict, observe, and record changes in matter caused by heating or cooling; NGSS 2-PS1-4.)

What You'll Learn

Cooling takes energy away — particles slow down.
Enough heating melts a solid into a liquid (ice → water at 0°C/32°F) or turns a
Enough cooling freezes a liquid into a solid (water → ice) or condenses a gas
The SAME matter is still there — only its state changed.

Words to Know

Melt: When a solid turns into a liquid from heating.; The ice cube melted in the warm pan.
Freeze: When a liquid turns into a solid from cooling.; The water froze into ice in the freezer.
Evaporate: When a liquid turns into a gas from heating.; The hot water evaporated into steam.
Condense: When a gas turns back into a liquid from cooling.; Steam condensed into drops on the cold lid.
Energy: The power that makes particles move faster or slower.; Heating adds energy; cooling takes it away.
State: The form matter is in — solid, liquid, or gas.; Water changed state from solid to liquid.

Check What You Learned

Quick Quiz

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What does heating do to matter's particles?

Fun Facts

Heating adds energy to matter and its particles move faster; cooling removes energy and particles slow down — enough change causes a state change
Source: kinetic particle model; NGSS elementary energy transfer framing
Ice melts to liquid water at 0°C (32°F) — the melting point of water
Source: standard physical property of water
Liquid water evaporates into water vapor (a gas) when heated; at 100°C (212°F) it boils rapidly
Source: standard physical property of water
Water vapor touching a cold surface condenses back into liquid drops — e.g. steam beading on a cold lid over a pot
Source: standard condensation definition
Liquid water freezes to solid ice when cooled to 0°C (32°F) — the freezing point equals the melting point
Source: standard physical property of water
The same matter persists through state changes — melting, freezing, evaporating, condensing do not create new substances
Source: conservation framing in TEKS 3.6C / NGSS 2-PS1-4

Lesson Info

Grade 3

2026-10-29

Standards Alignment

TEKS 3.6C
predict, observe, and record changes in the state of matter caused by heating or cooling such as ice melting, water evaporating, or condensation forming
2-PS1-4
construct an argument with evidence that some changes caused by heating or cooling can be reversed and some cannot
5-PS1-1
matter is made of particles too small to be seen