Changes of State Lab Grade 7 Science

Your Task Every two minutes one student will record the temperature of the ice or the water on the large chart, and make a short observation of the state of the substance. You will be doing this while taking notes so pay careful attention!

Particle Theory of Matter Grade 7 Science

What is matter? Matter is anything that takes up space and has mass – so everything around us! Matter comes in three main states: StateSolidsLiquidsGases Examples

What is matter? Fun Fact! There are two other states of matter: Plasma and Bose-Einstein condensates

What is the Particle Theory of Matter? The Particle Theory of Matter is how scientists explain how particles stay together as matter, and how particles behave when matter is in different states. The Particle Theory of Matter is made up of four main points.

Point 1 All matter is made up of particles

In any state (solid, liquid, gas), every object is made up of particles too small to see. These particles are called atoms and molecules. These particles are often referred to as “the building blocks of life”. Think Lego. Different substances have different part.

Example: Tearing Paper When you tear a piece of paper into smaller and smaller pieces, the molecules do not change. The fact that the paper tears implies that it is made up of smaller particles. If not, the paper would not tear.

Point 2 All particles are in constant motion

All particles vibrate, rotate, and move in straight lines. Think about when there’s a class in the tech room cooking up a delicious storm. How is that you can smell the food even upstairs? It’s because the particles in the air are moving!

All particles are in constant motion Particles move differently in the different states of matter.

Solid - definite size and shape. - particles in solids can only vibrate in one place.

Liquid - definite size and volume, but the shape can change. - particles are sliding around and over each other. Think: pouring.

Gases - no particular shape or size. - particles move as much as the space they are in allows. - particles can be compressed.

Point 3 There are spaces between particles

The size of the spaces varies with the state of matter. Which state do you think has the most space between particles? The least?

Solid - very little space between the particles You can’t walk through a door. The door is Solid.

Liquid - particles are arranged randomly - large spaces between particles You can swim in the water. There are some spaces in the Liquid.

Gas - very large spaces between the particles (as much as the space allows) You can walk around. There is enough space in the air to let you through.

Point 4 Adding heat causes particles to move faster

Think of your muscles. Before doing any aggressive physical activity, you have to warm up your body or you will pull something. When the particles of a solid are heated up, the particles take that energy and move around more.

Adding heat causes particles to move faster Red = taking away heat Blue = adding heat

Adding heat causes particles to move faster What are your observations from the changes of state lab? Do they support or refute this point of the Particle Theory of Matter?

Dictionary Time!

Melting Point The melting point is the temperature at which a solid turns into a liquid. Example, the melting point of water (ice) is around 0 degrees Celsius. 0 o Celsius

Boiling Point The boiling point is the temperature at which a liquid turns into a gas. Example: The boiling point for water is 100 degrees Celsius. 100 o Celsius