Week 9 · Theme 2 Matter and Energy, Unit 2 Particles in Motion, Concept 2.1 Matter in the World around Us (B) · 3 lessons
3
Modelling matter with buttons
Discovery Education Science P5: Term 1, Unit 2, pp. 142–146
GoalBuild a bean model of the three states and use particles to explain everyday heating.
New words
model · a way of showing how something worksmelt · to change from solid to liquid when heatedexplanation · a claim, evidence and reasoning put together
Explanation
You can build a model of particles from dry beans or buttons in a shallow tray. For a solid, pack the beans close together in neat rows and give the tray a very small shake. For a liquid, keep them close but not in rows, and shake a bit more so that they slide past each other. For a gas, use only a few beans in the same tray and shake it hard, so that they spread out and bounce. Shaking is like adding thermal energy. A chef’s kitchen uses this idea. A pat of butter in a warm pan melts because heat makes its particles move more until they slide. Rice cooks in a pot with a lid, and steam rises. The explanation uses a claim, evidence and reasoning: heat makes particles move more, so a solid can melt.
State
Beans in the tray
Shaking
solid
many, in rows
very gentle
liquid
many, no rows
a bit more
gas
only a few
hard
Worked examples
Tray
Beans
solid (4 rows of 6)
24
gas tray
6
left in the solid tray
18
Youssef’s tray holds 4 rows of 6 beans for the solid. He moves 6 beans to another tray for the gas. How many beans are left in the first tray? 4 × 6 = 24, and 24 − 6 = 18.
Butter in a warm pan melts. Heat makes its particles move more, so they leave their pattern and slide.
Part
What it says
Claim
Heat can make a solid melt.
Evidence
Butter is solid in the fridge and liquid in a warm pan.
Reasoning
Heat makes particles move more until they slide past one another.
The explanation about melting in three parts:
Class activity
Bean model. In a shallow tray use 12 beans in rows for a solid, the same 12 beans without rows for a liquid, and only 4 beans for a gas. Shake each one the right amount. Draw the three trays with dots. Tell a grown-up which part of the model is not like real particles.
Practice
1
In the bean model, how do you shake the tray for a gas?
Hard, with only a few beans so they spread out and bounce.
2
A solid tray has 3 rows of 5 beans. How many beans?
3 × 5 = 15 beans.
3
Why does butter melt in a warm pan?
Heat makes its particles move more until they slide past one another.
4
Which part of a claim, evidence and reasoning tells why the evidence supports the claim: the claim or the reasoning?
