Page 33 - 新思维科学学生用书7 样章

2 Materials and their structure

Think like a scientist

Particle theory

Scientists observe the world around them and think carefully about what they see.
Development of the particle theory was based on the observations that scientists
made about how solids, liquids and gases behave.

Scientists saw that most solids cannot be compressed. Can you think of any solids that
do not fit the rules of particle theory? Think about the properties of a sponge or

a marshmallow. Can a sponge be compressed?
Questions
1 Use particle theory to explain how a sponge can be a solid, but it can also

be compressed.
2 How well does particle theory explain the properties of solids, liquids and gases?
3 What are the strengths of the particle theory?
4 What are the weaknesses of the particle theory?

Activity

States of matter
On a large piece of paper, draw three large squares and label them ‘solid’, ‘liquid’
and ‘gas’, like this. Leave space around them.

Solid Liquid Gas

In each square, draw how the particles are arranged in that state of matter.
In the spaces around the squares, write the properties of the three states of matter.

Summary checklist

I can classify matter as a solid, liquid or gas.
I can list the properties of solids, liquids and gases.
I can describe the way in which particles are arranged in solids, liquids and gases.
I can explain the properties of solids, liquids and gases using particle theory.

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