Whole Earth Curriculum WEC

Lesson 06 — Heating and Cooling Change States

Learners discover that heating and cooling move matter between its states: heating melts a solid to a liquid and evaporates a liquid to a gas, while cooling freezes a liquid to a solid and condenses a gas back to a liquid. They watch water change before their eyes — ice melting, water evaporating, a puddle drying — and draw the change-of-state circle.

D06 P3: Intellectual & Cognitive Awareness D06.S3 55 minutes Draft

Objectives

Essential question

How do heating and cooling move matter between solid, liquid, and gas?

heatcoolmeltfreezeevaporatecondensechange of state

Materials

Standard materials

Low-tech / no-cost

Enriched / lab & device

Works in different contexts

A circle of water in three states — ice labeled solid, water labeled liquid, and steam labeled gas — with heating arrows labeled melt and evaporate going one way and cooling arrows labeled freeze and condense going back
A circle of water in three states — ice labeled solid, water labeled liquid, and steam labeled gas — with heating arrows labeled melt and evaporate going one way and cooling arrows labeled freeze and condense going back

Lesson 6 — Heating and Cooling Change States

Summary

Water is the perfect teacher for change of state. Learners watch the same matter move between its three states: heating melts a solid into a liquid and evaporates a liquid into a gas, while cooling freezes a liquid into a solid and condenses a gas back into a liquid. They hold ice as it melts, watch a wet mark dry, and draw the circle that water travels — the same circle happening in kitchens, rivers, and skies everywhere.

Objectives

  • Describe the three states of matter (solid, liquid, and gas) and how heating and cooling change them. (D06.S3.03.01)

Connection

You have seen this a hundred times: an ice cube melts into water in your warm hand; a puddle dries in the Sun; steam condenses into little drops on a cool window. That is one substance — water — moving between solid, liquid, and gas. Heat pushes it one way; cold pulls it the other. The same circle is making the rain and the snow and the clouds above your head, wherever you live.

Materials

  • Ice cubes and a warm spot
  • A small cup of water and a cold place or freezer
  • A warm, wet mark on a surface
  • Paper and crayons

Preparation

  • Have ice cubes, a warm spot, and (if possible) a freezer or very cold place ready.
  • Make a wet mark on a smooth surface to watch it dry over the lesson.
  • If using a kettle or pan for steam, an adult operates it and keeps hands clear.

Facilitator note

This lesson is written to the learner (“you”). Anchor the four words — melt, freeze, evaporate, condense — with concrete, watched examples before the circle is drawn (concrete before abstract). Model once (worked example: “heat melts ice”), then let pairs test one change themselves. Note the four changes are reversible — matter is not created or destroyed here, just rearranged (a first seed of the conservation idea, deepened in Grade 4). Keep the global lens: the same freezing, melting, and evaporating waters a rice field, carves a river, and clouds a sky anywhere on Earth. If boiling water is shown, an adult handles the heat, and learners watch at a safe distance — no fear, just care. Distinguish the evidence (what we watched happen) from the words we use to name it; the names are tools.

Procedure

  1. Gather and remember (5 min). Last lesson you met the three states: solid, liquid, gas. Today: what makes matter change from one to another? The answer is heat and cold.
  2. Heat melts and evaporates (15 min). Hold an ice cube and watch it melt — a solid becomes a liquid. Watch a wet mark slowly dry in the warm air — the liquid evaporates into a gas you cannot see. Say the two heat words: melt, evaporate.
  3. Cold freezes and condenses (10 min). Put a small cup of water somewhere cold and predict what will happen: it will freeze into a solid. If you have steam or a cold window, watch a gas condense back into liquid drops. Say the two cold words: freeze, condense.
  4. Draw the circle (15 min). Draw water in its three states — ice, water, steam — in a circle. Draw arrows with the right words: heating goes melt → evaporate; cooling goes freeze ← condense.
  5. Close (5 min). Heat and cold are the hands that move matter between its states. The ice in your cup, the drying puddle, and the clouds in the sky are all the same water, changing.

Differentiation

  • Support: Match two changes (ice melts, water freezes) to their names with a partner.
  • Support (non-speaking): Point to the ice melting or the mark drying; a partner says the word.
  • Support (blind/low-vision): Feel ice melt in your hand and feel the cool of your wet hand drying; name each change by telling.
  • Support (motor): Direct a partner to hold the ice and wet the mark while you watch and name each change of state.
  • Extension: Trace one water drop’s full journey through all four changes and tell where each might happen in the world.

Assessment

  • Formative (observation): Can the learner name at least two changes of state and say whether heat or cold causes each?
  • Artifact (portfolio): The labeled change-of-state circle drawing.

Home connection

At home, watch a change of state with a grown-up: an ice cube melting in a cup, a wet cloth drying on a line, or breath fogging a cold window. Name the change together.

Resources