how science works, hsw, particles, elements

1. 3.11 Imagine something unseen
28 January 2015
How does
anyone know
what I look like?

2. Aims
• Learn how evidence from experiments and
creative thinking can give us scientific
explanations
• Learn early scientific ideas about matter

3. An ancient tale
• Six men were asked to work out what an
elephant is like. But instead of looking at one,
they had to touch it in the dark. The man who
touched the tail thought it was a rope, and the
man touched the trunk thought it was a
snake. A tusk was mistaken for a spear, a leg a
tree trunk and an ear for a fan. The man who
touched the elephants side thought it was a
wall.

6. Are particles real?
• If we cannot see these particles, how do we
know they are real?

7. Early ideas
• Ancient Greeks though
everything was made
of four elements, and
they were different
because of their
different proportions
• Fluids flow so their
particles were
rounded, solids had
jagged particles

9. 3.11 Imagine something unseen
Questions
1. Which of the two models of gases described
on page 87 is used today?
2. What could the men in the Indian story on
page 86 have done to collect accurate
evidence about the elephant?
3. Why do scientists use models?
4. Suggest why the designers of large buildings
use models to check their designs before
building work starts.
(Level 3)
(Level 4)
(Level 5)
(Level 6)
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10. 3.11 Imagine something unseen
Questions
5. Why do gases expand to fill their container?
Use the model of gas particles that push
each other away in your explanation.
(Level 7)
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11. 3.11 Imagine something unseen
For your notes
 Scientists use models to explain things that
are observed.
 The same thing can be explained by different
models.
 Scientists will change to using a different
model if someone comes up with one that
explains things better.
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