Topic 2: Heat Affects Matter in Different Ways

Transcription

1 Topic 2: Heat Affects Matter in Different Ways 1

2 2.1 States of Matter and the Particle Model of Matter A. States of 1. Matter is made up of tiny particles and exist in 3 states:, and. 2. Matter can change its state by or away heat energy. 3. Heat energy: a form of energy that from matter at a higher temperature to matter a lower temperature. 2

3 B. Water s Changing State 1. Water can undergo changes through all three states of matter: a) The point of water is 0 C. b) The point of water is 0 C. c) The point of water is 100 C. d) When water that is a gas loses heat energy and becomes a liquid, we call the process. This occurs at 100 C. C. Particle Model of Matter 1. All matter is made up of extremely particles. 2. The tiny particles of matter are always. 3. Adding heat to matter makes the particles move around. 4. The particles have between them. 3

4 D. Heat and the Particle Model of Matter 1. Particles are always moving because they have energy. a) Kinetic energy energy of 2. Solid State a) Has a definite and. b) Particles move back and forth around a point. 3. Liquid State a) Takes the shape of its but has a definite volume. b) Particles can easily past each other. 4. Gas State a) Particles are not to each other. b) No set shape or. c) There are spaces between particles. d) Particles are moving much. E. The Effect of on Particles 1. When heat is, the particles move faster. 2. When heat is, the particles move slower. 3. Heat energy transfers from temperature matter to temperature matter. Melting aluminum 4

5 F. How the Particle Model Explains Changes in State 5

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7 2.2 Heat and Temperature A. Introduction 1. Temperature: a measure of how or cold matter is. B. Thermal Energy 1. The kinetic energy of all the particles the substance contains. 2. The soup in the pot has more thermal energy because it contains more. C. Energy Transfers 1. Scientists use the word to mean the energy that transfers from one substance to another because of differences in kinetic energy. 2. So, in our soup example, the soup became hot because kinetic energy from the particles in the hot stove burner to the cooler soup. D. The Between Heat and Temperature 1. Heat energy transfers from areas where particles have kinetic energy to areas where particles have kinetic energy. 2. Temperature is the kinetic energy of the particles in a substance, the hotness or coldness of an object. 7

8 E. Understanding the Difference 1. Thermal Energy a) The total kinetic energy of the particles in a substance. 2. Heat a) The that transfers from a substance whose particles have a kinetic energy to one whose particles have kinetic energy. 3. Temperature a) A measure of the average kinetic energy of the particles of a. 8

9 Topic Heat Affects the Volume of Solids, Liquids and Gases A. Observing the of Heat 9

10 B. Expansion and Contraction of 1. The particle model of matter tells us that when the thermal energy of a solid, so does its volume. a) We say that the solid, which occurs when heat transfers to a solid. 2. When the thermal energy of a solid, its volume decreases, and the solid contracts. a) This occurs when heat transfers from the solid to matter. 10

11 C. Heat Affects the of Liquids and Gases 1. Liquids and gases will also when their thermal energy increases. 2. And they will when their thermal energy decreases. 3. Liquids expand than solids but not as much as gases do. D. Expansion and Contraction in Liquids and Gases 1. We see expansion of liquid in a. a) As the liquid inside (usually alcohol) warms up, it expands and up the narrow glass tube. b) As it cools off, it. 2. It s the same with gases. Why are the balloons? 11

12 Topic Heat Transfers by Conduction A. Conduction 1. One way that heat transfers through matter is by. 2. Conduction is the of heat energy between substances that are in contact with each other. 3. None of the particles move from one part of the substance to another, they simply transfer energy by into each other. 12

13 B. Conductors 1. One of the key characteristics of conduction is that heat transfers in only direction from areas of greater kinetic energy to areas of less kinetic energy. 2. That is, heat transfers from areas having thermal energy to areas having less thermal energy. 3. Conduction is most common in. 4. Materials that allow easy transfer of are called conductors. a) Metals are of good conductors of energy. C. Insulators 1. Insulators are materials that do not allow transfer of heat. 2. They the amount of heat that can transfer from a hotter object to a colder one. 3. Plastic,, and are good insulators, which means they are poor conductors of heat. 13

14 Topic Heat Transfers by Convection and Radiation A. Understanding Convection 1. In convection, heat is transferred when liquid or gas particles from one area to another. 2. Convection a) Heat transfer by convection occurs when the particles in a or move in circular patterns called convection currents. 14

15 B. Convection Currents in 1. As with conduction, heat transfers by convection move in only direction. It moves from an area of kinetic energy to one of kinetic energy. 2. As air heats up near a heater, it, becomes less dense and rises. Cooler air takes its place, becomes heated and rises. Convection currents form from this. C. Heat Transfers by 1. Radiation is a way that heat transfer occurs. 2. Conduction and convection rely on the movement of particles to transfer heat energy, does not. 3. Radiation is the transfer of energy by waves that can travel great distances. 4. Energy transferred from its by radiation is called radiant energy. 5. Heat is transferred by invisible waves called waves. 6. When the invisible radiant energy waves come in with an object, the particles in the object increase in kinetic energy. a) The particles move and the object becomes hotter. 15

16 D. Reflect or 1. Matter can reflect or radiant energy. 2. Objects that are and coloured are good reflectors. 3. Dark and objects are good at absorbing radiant energy. Topic

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