There are three phases of water. Water can transition between these phases via six different phase changes. In this post, learn about each one, then try out the phases of water classroom activity at the end!
A note for teachers: you’ll find lessons on the phases of water, phase changes, water molecule properties, snow-water equivalent calculations, and much more in my Science in the Snow Unit. It’s an applied STEM unit with a wintery theme and packed with hands-on activities. Plus, every purchase helps support this blog!
Ice (solid)
Water molecules are packed closely together and bonded in a rigid pattern, such that they cannot move past one another. Like other solids, ice:
- Does not take the shape of its container
- Does not expand/compress to fill its container
Liquid Water
Water molecules are packed very closely together but are still moving and slide freely past one another. Like other liquids, liquid water:
- Takes the shape of its container
- Does not expand/compress to fill its container
Water Vapor
Water molecules are far apart from one another and move very rapidly and freely. Like other gases, water vapor:
- Takes the shape of its container
- Expands/compresses to fill its container
Phase Changes
Solid → Liquid
Melting – the process of changing from a solid to a liquid, due to an addition of energy (heat).
Solid → Gas
Sublimation – the process of changing from a solid to a gas, without passing through the liquid phase, due to an addition of energy (heat).
Liquid→ Solid
Freezing – the process of changing from a liquid to a solid, due to a loss of energy (heat).
Liquid→ Gas
Evaporation – the process of changing from a liquid to a gas, due to an addition of energy (heat).
Gas→ Liquid
Condensation – the process of changing from a gas to a liquid, due to a loss of energy (heat).
Gas→ Solid
Deposition – the process of changing from a gas to a solid without passing through the liquid phase, due to a loss of energy (heat).
Phases of Water Venn Diagram Activity
For this activity, students will use a Venn Diagram with three circles to compare ice, water, and vapor.
- Label the three sides of the diagram: ice, liquid water, and vapor.
- Students should read the descriptions below, then decide where each description belongs on the Venn diagram:
- Takes the shape of its container
- Does not take the shape of its container
- Its volume expands to fill up its container
- Does not expand to fill its container
- Compressible
- Nearly incompressible
- Flows
- Does not flow
- Forces between molecules keep them in an organized pattern
- Molecules can move past each other
- Molecules sliding very closely past one another
- Molecules are very far apart
- Made of hydrogen and oxygen
- The densest of the 3 phases (Hint 1: when are the molecules closest together? Hint 2: think about what sinks vs. floats.)
- Think of a few of your own to add!
- You can find the worksheets for this activity, an answer key, phase change diagrams and more in my Phases of Water Mini Study:
Study Water and Ice with Wild Earth Lab:
The information and activities in this post come from my complete Science in the Snow Unit. Grab the full unit from my shop:
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