Day 14 of 30
Changes of state: melting and freezing
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Learning Objective
Students will be able to explore changes of state and melting and freezing.
In this lesson, we'll explore changes of state: melting and freezing. Scientific inquiry allows us to investigate and explain natural phenomena.
Matter exists in different physical states based on particle arrangement and energy. Solid: particles are tightly packed in a fixed arrangement; solids have definite shape and volume. Liquid: particles are close but can flow past each other; liquids have definite volume but take the shape of their container. Gas: particles are far apart and move rapidly in all directions; gases have neither definite shape nor volume—they expand to fill any container. Plasma: a high-energy state (stars, lightning) where electrons are stripped from atoms. Changes of state occur when energy is added or removed: melting (solid → liquid), freezing (liquid → solid), evaporation (liquid → gas), condensation (gas → liquid), sublimation (solid → gas), deposition (gas → solid). These transitions involve absorbing or releasing heat without a temperature change.
As you work through today's material, pay attention to the examples and try to identify the patterns or strategies being used. This will help you apply these concepts to new problems.
Take notes on key points and make connections to what you've already learned in previous lessons.
To examine systematically through observation and experiment
Observable facts that support or refute a claim
Instructions
Materials Needed
- Lab notebook
- Investigation materials
- Safety equipment if needed
Based on today's lesson, what is one thing you observed or learned?
How could you test or investigate this topic further?
Why is this topic important in the real world?
Teaching Tip
For this age group: Balance direct instruction with collaborative activities. Allow students to explain their thinking and make connections to prior knowledge when exploring changes of state: melting and freezing.