solids, liquids and gases 7G Particle model of solids, liquids and gases 7G Particle model of solids, liquids and gases What is the world made of? Solids, liquids and gases The particle model

What is the world made of? 7G Particle model of solids, liquids and gases What is the world made of?

7G What is the world made of? - Big questions

Greek thinkers thought everything was made up of 4 things: 7G What is the world made of? - Ancient thinkers Since ancient times the greatest thinkers have tried to understand and group the world around them. Greek thinkers thought everything was made up of 4 things: TEACHER’S NOTES The material on this and the following slide could be used to discuss why people come up with different theories.

In India they added a fifth group: 7G What is the world made of? - Ancient thinkers In India they added a fifth group: The ancient Chinese had a slightly different view. They believed the universe was made up of 5 components: TEACHER’S NOTES The material on this and the previous slide could be used to discuss why people come up with different theories.

A theory is an idea that explains observations. 7G What is the world made of? - Creating a theory A theory is an idea that explains observations. Scientists, like ancient thinkers, are curious about the world. They carry out investigations and produce theories about what they see. But a theory doesn’t just appear by itself! Creating a good theory involves several stages. The following stages are in the wrong order. Put them in the right order and explain your answer. evidence theory observations conclusion data prediction Answer- prediction observations data evidence conclusion theory

Solids, liquids and gases 7G Particle model of solids, liquids and gases Solids, liquids and gases

Everything in the Universe is made of matter. 7G Solids, liquids and gases - It’s a matter of fact! Everything in the Universe is made of matter. Matter is all the stuff around you – everything you can touch, see or smell. There are 3 states of matter…

7G Solids, liquids and gases - It’s a matter of fact!

A useful starting point is to think about their shape and volume. 7G Solids, liquids and gases - In a state! You can investigate solids, liquids and gases to understand how they behave. A useful starting point is to think about their shape and volume. TEACHER’S NOTES - clarify definitions and distinction between “shape” and “volume”

solid liquid gas fixed shape fixed volume 7G Solids, liquids and gases - In a state! Fill in the table with the answers to these testing questions: Does it have a fixed shape? Does it have a fixed volume? solid liquid gas fixed shape fixed volume TEACHER’S NOTES - answers not revealed here - space to fill in answers - complete by adding tick/cross on whiteboard - students copy and complete own version of table

Does it conduct heat well? 7G Solids, liquids and gases - In a state! Now answer some more testing questions about a solid, a liquid and a gas. solid liquid gas Is it easy to squash? Does it conduct heat well? Can it spread out? Can it stretch? Is it heavy for its size?

7G Solids, liquids and gases – What are they made of?

7G Solids, liquids and gases – What are they made of? You can do the same “splitting experiment” if you think about a liquid or a gas. Solids, liquids and gases are all made of tiny particles. This is called the particle theory. TEACHER’S NOTES But just how small are these particles?

7G Particle model of solids, liquids and gases The particle model

He also thought about the size of these particles. 7G The particle model - The necklace of Democritus Democritus, an ancient Greek thinker, was one of the first to suggest the idea of particles. He also thought about the size of these particles. Democritus considered the particles in a grain of salt (one millimetre cubed).  

Imagine you could take apart all the particles in this grain of salt. 7G The particle model - The necklace of Democritus Imagine you could take apart all the particles in this grain of salt. How long would the row of particle be? Would it be long enough to make a necklace? Next you arrange all the particles in a row.

7G The particle model - The necklace of Democritus Democritus never found out the answer to his salty puzzle. Thousands of years later, we know just how long the row of salt particles would be… 12 900 000 000 metres That’s more than 33 times the distance from the Earth to the Moon!   All that from just one grain of salt! What does tell us about the number and size of the particles?

So next time you pour salt on your chips 7G The particle model - The necklace of Democritus The number of particles is very, very, very, very, very, very, very, very, very, very ,very, very big! The size of the particles must be very, very, very, very, very, very, very, very, very, very, very small! So next time you pour salt on your chips spare a thought for all those tiny salt particles!

Solids, liquids and gases behave in different ways. 7G The particle model - From theory to model Solids, liquids and gases behave in different ways. What does this tell us about their particles? A theory is an idea that explains observations. Scientists use a model to give a mental picture of what is happening in their investigation. TEACHER’S NOTES make link to students observations about properties of a solid, a liquid and a gas Any theory about particles must be able to explain the differences between a solid, a liquid and a gas.

The particle model of matter describes: how particles are arranged 7G The particle model – Solids, liquids and gases The particle model of matter describes: how particles are arranged how much energy particles have and how they move    In some matter the particles are held together by forces of attraction. TEACHER’S NOTES - use the following animations to consider how the particle model explains the behaviour of solids, liquids and gases? Use the particle model to decide if the forces of attraction are strong, weak or do not exist.

The particle model of a solid 7G The particle model – Solids, liquids and gases The particle model of a solid

The particle model of a liquid 7G The particle model – Solids, liquids and gases The particle model of a liquid

The particle model of a gas 7G The particle model – Solids, liquids and gases The particle model of a gas

- are very close together in a fixed arrangement 7G The particle model – Solids, liquids and gases solid particles… - are very close together in a fixed arrangement - have a small amount of energy - vibrate but do not move   liquid particles… - are close together but have no fixed arrangement - more energy than solid particles - vibrate and can move about   TEACHER’S NOTES - use the following animations to consider how the particle model explains the behaviour of solids, liquids and gases? gas particles - are far apart and have no fixed arrangement - have a large amount of energy - move rapidly in all directions  

Water can be a solid, liquid or a gas. 7G The particle model – Changing state Water can be a solid, liquid or a gas. Its state depends on how much energy the water particles have. ice water steam If enough energy is added to or removed from the particles a change of state can occur.

freezing condensing melting evaporating 7G The particle model – Changing state Match the change of state to the correct arrow on the diagram. freezing condensing melting evaporating   ice water steam What happens to the particles during each change of state? CLUE: Think about their energy, their movement and the distance between them.

True or False? 1. The particles in gas have a large amount of energy. 7G The particle model – True or false? True or False?   1. The particles in gas have a large amount of energy. 2. The particles in a solid have no forces of attraction between them. 3. The particles in a liquid are close together and have a fixed arrangement. 4. When a liquid freezes it becomes a gas. 5. Evaporation describes the change from a liquid to a gas. 6. When a liquid loses energy it becomes a gas. 7. A gas condenses to a liquid when its particles lose energy. 8. When the particles in a solid gain energy the solid melts. TRUE FALSE FALSE FALSE TRUE FALSE TRUE TRUE