Scientists use the Particle Theory of Matter to describe temperature. Grade 7 Science Unit 2 Scientists use the Particle Theory of Matter to describe temperature. Chapter 5

Discussion What are objects (or matter) made up of? What makes something an object (matter) in real-life?

Matter Matter: Is anything that has mass and takes up space. Mass is measured in kilograms (it’s related to how heavy something is) Taking up space means volume – Big (an elephant) or small (a bacteria)

So what makes up matter? If we had the best microscopes in the world and we looked at matter – what is it made up of?

So what makes up matter? If we had the best microscopes in the world and we looked at matter – what is it made up of? Particles! – also called atoms (sadly we can’t see them with our microscopes!)

The Particle Theory of Matter! 5 points about this theory: All matter is made up of tiny particles.

Particle Theory of Matter These particles are always moving –they have energy. The more energy they have, the faster they move.

Particle Theory of Matter There is space between all particles. Mini Activity: Pg. 137, 5-1A

Particle Theory of Matter There are attractive forces between the particles.

Particle Theory of Matter The particles of one substance are the same but different from another substance.

Particle Theory of Matter Iteractive to relate to the PTM: http://phet.colorado.edu/en/simulation/legacy/states-of-matter-basics

Particles have Energy PTM #2 says all particles have energy This is important for Temperature! If particles have more energy will they be hotter or colder?

Particles have Energy PTM #2 says all particles have energy This is important for Temperature! If particles have more energy will they be hotter or colder? Hotter!

Particles have Energy kinetic energy: The energy that particles have due to motion (moving) Measured in Joules or J Moving faster means they have more energy! Does this relate to temperature?

Temperature Temperature: The average energy of the particles of a substance.

Question 1: “All particles in a glass of room temperature water are moving at the same speed.” Explain whether this statement is true or false.

Question 2: “Will the particles of air closest to a sunny window have the same amount of kinetic energy as those near the floor?” Explain

Kenetic Energy Do all the particles have the same energy? The kinetic energy is the average of all the particles energy

Kenetic Energy Do all the particles have the same energy? The kinetic energy is the average of all the particles energy 12.9J

What is the kinetic energy of the matter in the following test tubes?

What is the kinetic energy of the matter in the following test tubes? 10J 15.8J

Review Questions Page 145 Q’s: 1, 2, 3, 4 & 8

Matter can be in different States Matter can change depending on how much energy it has What will happen to ice water if I add energy to it? What will happen to liquid water if I add energy to it?

3 States of matter

Observe the differences between the 3 states of Matter http://phet.colorado.edu/en/simulation/legacy/states-of-matter-basics

Discussion How are these three states different from one another?

Expands to fit the container Solid Liquid Gas Volume Does Not Change Expands to fit the container Shape Does not take the shape of the container Takes the Shape of the container *flat top Particle arrangement Closely packed together Close together, but can slide past each other Large spaces between them Particle movement Vibrate in the same position Slide past one another Moves freely in all directions Drawing

Interactive and Quiz: http://www.bbc.co.uk/education/guides/z2wmxnb/activity

*Important note When energy is added or removed the state of matter can change!

Adding Heat When heat is added what happens: Do the particles change into new ones? Do the particles change speed? Do the particles have different amount of space between them?

Adding Heat When heat is added what happens: Do the particles change into new ones? No! Do the particles change speed? Yes they move faster! Do the particles have different amount of space between them? Yes - more, especially if it becomes a gas

When heat is added the volumne increases! Expansion Increasing the volume of a substance Contraction Decreasing the volume of a substance

Expansion When the particles are heated, they: gain energy, move faster, spread out and take up more space thereby increasing their volume.

Contraction When the particles are cooled: they lose energy, move slower, move closer together and take up less space thereby decreasing their volume.

Explaining why Why does air pressure in tires increases during a car trip? Why do footballs or soccer balls deflate when they are taken outside on a cold day?

Activity Day! 1. Activity 5-2 B “Bulging Balloons” 2. Activity 5-2 C “Race to for the Top” 3. Activity 5-2 D “ Expanding Solids” Pages 151 -155

Review Questions Page 157 Q’s: 2, 3, 4, 9 & 10

Changing States Adding or removing heat changes the state of matter by changing the movement of the particles * the type of particles does NOT change, just there motion

Changes of State

Changing State interactive http://www.bbc.co.uk/schools/scienceclips/ages/9_10/changing_state_fs.shtml

We can graph the changes of state by observing temperature Core Lab activity Activity 5-3C “The Plateau Problem” Page 166 (7)

* When matter is changing state all the energy is used up, so temperature does NOT increase!

Review Questions Page 169 Q’s: 1, 2, 3, 4, 7 & 8

Chapter Review Questions Page 170-171 Q’s: 1, 2, 3, 4, 5, 7, 8, 11, 13, 15 & 18