WLWeather Lab NC

Day 7 of 30

Phase Changes and Energy

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Learning target

I can explain whether water absorbs or releases energy during each phase change.

Essential question

How can water change state without changing identity?

Scaffolded notes

Build the idea

1

Adding energy spreads particles

Melting, vaporization, and sublimation require water to absorb energy from the surroundings. Particle motion increases and attractions are overcome. Evaporation is vaporization from a liquid surface and can occur below the boiling point.

2

Removing energy brings particles together

Condensation, freezing, and deposition occur when water releases energy to the surroundings. Gas particles slow and form liquid droplets during condensation. Liquid particles organize into a solid during freezing.

3

Phase changes shape weather

Evaporation transfers water and energy into the atmosphere. Condensation forms cloud droplets and releases energy that can strengthen rising air. Freezing and melting influence precipitation type and surface conditions.

Stop and explain

Check your thinking

1. Does condensation absorb or release energy?

Possible response: It releases energy to the surroundings.

2. Why can evaporation cool a surface?

Possible response: The highest-energy liquid particles escape, taking energy with them.

Interactive challenge

Try the science

Match each phase change to its energy direction.

Before you leave

Exit ticket

Name one energy-absorbing and one energy-releasing phase change.