1. Solids, Liquids and Gases
Three States of Matter
Solids, Liquids and Gases

2. Three States of Matter
Have you ever seen a snowflake under a microscope?
Can you tell what kind of matter it is made of? How could you find out?

3. Three States of Matter Snowflakes are a form of solid water
Water particles are always water particles, whether in solid (ice), gas (vapour) or liquid (water) form
The particles of water are exactly the same in each state; individual particles do not freeze or melt, instead, their movement changes
Additionally, the arrangement of particles is different in each state
Matter behaves differently in each state

4. Solids A solid has a definite shape and a definite volume
Volume is the quantity (amount) of space something occupies
For example, a coin is made of metal, and the metal is in its solid state, therefore, the coin’s shape and volume remain constant (as long as the temperature doesn’t change)
Particles of a solid are like students sitting in a movie theater,
watching a movie; students have a bit of distance between
them, they can sit and fidget in their seats, but they cannot
move around very much

5. Liquids
A liquid has a definite volume, but does not have a definite shape.
A liquid takes the shape of its container (eg. Milk can be held in a 1L carton, or a 1L bag, and in both cases, the volume of milk will also be 1L)
The volume does not change but the shape can change
Particles of a liquid are like students moving
moving through a busy shopping mall.
Students can move around, but are still
close together

6. Gases A gas does not have a definite volume or a definite shape
The gas takes on the shape and the volume of its container
Eg. When a deflated basketball is filled with air, the air particles occupy a spherical space and a volume equal to the volume inside the inflated ball
Particles of a gas are like students running out of
school on the last day of school.
Students can move quickly, and in all different
directions

7. Testing The Particle Theory
Questions
Part A: What happens to the mass of a solid when it melts?
Part B: How does mixing a solid and a liquid together (until the solid disappears) affect the total mass of the mixture?
Prediction: Write a prediction for each testable question, on your P.E. O.E work sheet. Each prediction should have a reasonable explanation for your prediction, based on the particle theory
PEOE Demonstration

8. Testable Question: Part A
What happens to the mass of a solid when it meltS?
When substances change state there is no change in mass, so if 100 g of ice is melted, 100g of water are formed and if this is boiled it will form 100g of steam (this is called "conservation of mass").
If this steam could be collected, cooled and condensed it would form 100g of water which could be frozen to give 100g of ice.
Children often think that solids get lighter when they melt as liquids are lighter than solids.

9. Testable Question: Part B
How does mixing a solid and a liquid together affect the total mass of the mixture?
We know that matter can neither be created nor destroyed, and the salt has dissolved in the water, creating a salt-water solution
No new matter has been created, nor has it been destroyed, so it makes sense that the mass of the mixture is equal to the mass of the water + the mass of the salt added to create the mixture