PUT THIS IN YOUR NOTEBOOK SC.7.P.11.1- Recognize that adding heat to or removing heat from a system may result in a temperature change and possibly a change of state. SC.7.P.11.4- Observe and describe that heat flows in predictable ways, moving from warmer objects to cooler ones until they reach the same temperature PUT THIS IN YOUR NOTEBOOK Vocabulary Vaporization Temperature Equilibrium Convection Thermal Conductor Conduction Thermal Insulator Radiation Heat

Essential Questions What is the difference between heat and temperature? How does an increase or decrease in heat affect molecules? What causes a change of state in matter? What are the predictable ways that heat flows?

Kinetic Molecular Theory Helps explain the movement of particles in matter. Has 3 main points All matter is made of tiny particles, like atoms and molecules These particles are in constant, random motion These particles constantly collide with each other and with the walls of their container.

Particle Speed in Matter Solid- particles vibrate in place (SLOW) Liquid- particles slide past each other (FASTER) Gas- particles move freely (FASTEST)

Thermal Energy The sum of the kinetic energy and the potential energy of the particles that make up an object The more molecules an object has, the more thermal energy it has.

Temperature The measure of the average kinetic energy in the particles in a material. If an object feels cold, it’s molecules have low kinetic energy. The SI unit for temperature is Kelvin (K), but scientists often use Celsius (C). In the US, we usually use Fahrenheit (F) to measure temperature.

Temperature Scales Kelvin (K) Celsius (C) Fahrenheit (F) Water Boils At: Water Freezes At: Kelvin (K) Water boils at 373K Water freezes at 273K Absolute Zero (coldest possible temperature) means no movement of particles. 0K Celsius (C) Fahrenheit (F) Water boils at 100C Water boils at 212F Water freezes at 0C Water freezes at 32F

Heat The movement of thermal energy from a region of higher temperature to a region of lower temperature Thermal energy ALWAYS moves from warm to cold. Eventually, both objects will reach thermal equilibrium. The molecules inside the warmer object will transfer some heat to the molecules inside the colder object until they have the same temperature.

Heat Transfer There are three types of heat transfer: Convection Conduction Radiation

Conduction The transfer of thermal energy by collisions between particles in matter. In other words… heat is transferred through direct contact . Molecules transfer energy to the molecules next to them.

Convection The transfer of thermal energy by the movement of particles from one part of a material to another. In other words, through the movement of currents (circular) Warm air/liquids are less dense and rise, cool air liquids are more dense and sink.

Radiation The transfer of thermal energy by electromagnetic waves. In other words, no direct contact needed.

Heat Transfer

So what happens to matter when heated/cooled? Most materials contract (shrink) when they are cooled…. and expand (grow) when they are heated. This happens because as we have already learned, molecules move faster (and occupy more volume) when heated and slower (occupy less volume) when cooled. This is called thermal expansion and thermal contraction. Water is an exemption to thermal contraction… when it cools down, it expands.

When thermal energy is added or removed from a system…. At the very least, a temperature change occurs. If enough thermal energy is added or removed, a change of state occurs.

Changes Between Solids and Liquids Heat Heat (make cold)

Changes Between Liquids and Gases Heat Heat (make cold)

Changes Between Solids and Gases Heat Heat (make cold)

Conductors and Insulators A thermal conductor is a material in which thermal energy moves quickly- it transfers thermal energy easily Usually made of more dense materials A thermal insulator is a material in which thermal energy moves slowly- it does not transfer thermal energy easily Usually made of less dense materials

Heat Transfer Lab

Where does heat transfer on this beach? Label at least four examples of heat transfer on the picture.

Diagram Answers: