States of matter
Properties
Reversible changes
Irreversible changes
Surprise me!
100
Name the three states of H2O.
Ice - water - vapour (or steam).
100
Name the opposites:
hard - ...,
rigid - ...,
brittle - ...
hard - soft,
rigid - flexible (bendy),
brittle - tough (strong).
100
What is this change called?
Dissolving
100
What is this change called?
Rusting
100
Name four natural materials.
Clay, wood, cotton, leather, cork, iron, gold, wax, glass, paper...
200
What kind of change is it?
Condensation - from gas to liquid.
200
Name the three properties shown here.
Transparent - translucent - opaque
200
How to separate rice grains and beans?
We can separate them by sieving.
200
Act out (like in a Drama class) how a raw egg becomes a fried egg.
It is heated and it is changed with no return...
200
Why does oil look separate from water?
Oil is INSOLUBLE in water, we can only mix them.
300
Show a word that I will give you with pantomime so that somebody can guess it.
A person who guesses the word will get the points as well!
300
Wood and glass here are...
Electrical insulators
300
Act out (like in a Drama class) how a gas becomes a liquid and then a solid.
Fast motion - slow down - freeze. Or take a lot of space - squeeze - shrink a lot.
300
Why cannot we turn this change back?
It is a chemical reaction. A new substance was made (gas was released), so we cannot get soda and vinegar back.
300
Find and show a flexible and translucent electrical insulator in 30 seconds.
Any translucent plastic or glass object, tracing paper, nylon or a similar fabric.
400
The melting point of gallium is 30℃ and the boiling point is 2400℃. Can you hold a liquid gallium in your hand? Explain.
Yes, you can. At body temperature (36.6℃) gallium melts and becomes liquid.
400
Odd one out. Explain.
Nylon – hard – magnetic – electrical conductor – opaque.
Nylon is the odd one out. It is soft, non-magnetic and translucent electrical insulator.
400
Odd one out! Explain.
Fuel burning in a car engine - cooking pasta in a boiling water - melting gold to make a crown - wood rotting in water.
Melting gold to make a crown. It is the only reversible change here.
400
Explain what happens here. Why is it an irreversible change?
1 - Evaporating wax was touched with a flame and lit up a candle again.
2 - Wax is melting and then burning out, so we cannot get it back.
400
What substance can be found on Earth in all three states in the same place at the same time?
Water
500
Why do liquids can take a shape of their containers AND cannot be compressed?
1 - Particles in a liquid can move, so liquids can flow.
2 - Particles in a liquid are close to each other.
500
Why do we need to change properties of materials? Give three reasons.
To make new objects (melt, evaporate, freeze to change shape).
To improve existing properties (iron-steel).
To make new materials with useful properties.
500
You mixed salt and pepper of the same grain size. How could you separate them?
Add water to dissolve the salt, then pour the salt water through a filter (separate pepper), then evaporate water (to get the salt back).
500
What material is this? What are the improved properties (name two)?
Gorilla Glass. It is harder (scratch-resistant) and tough (hard to break down).