Big Idea 11: Energy Transfer and Transformations A. Waves involve a transfer of energy without a transfer of matter. B. Water and sound waves transfer energy through a material. C. Light waves can travel through a vacuum and through matter. D. The Law of Conservation of Energy: energy is conserved as it transfers from one object to another and from one form to another.

Benchmark Number & Descriptor 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.11.2 Investigate and describe the transformation of energy from one form to another. SC.7.P.11.3 Cite evidence to explain that energy cannot be created nor destroyed, only changed from one form to another. 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. Benchmark Number & Descriptor

Temperature Measure of kinetic energy of molecules Measured with a thermometer 3 Scales Fahrenheit Celsius Kelvin F = Fahrenheit (used for weather) Water boils at 212°F. Water freezes at 323° F. C = Celsius (used in science) Water boils at 100°C. Water freezes at 0°C. K = Kelvin (used in science) Only scale that has absolute zero Particles are said to have no movement at this temp. Temperature

Thermal Energy A B Which beaker of water has more thermal energy? 80ºC * 07/16/96 The total energy of the particles in a material Depends on temperature, mass, and type of substance Which beaker of water has more thermal energy? B - same temperature, more mass 200 mL 80ºC A 400 mL B Thermal Energy *

HEAT is the transfer of energy from one object to another when the two things are at different temperatures and in some kind of contact. Always transfers from hot to cold Ex: Teapot heats on stove top cup of tea cools down (loses energy as heat) HEAT

Heat Transfer Heat is always transferred from hot to cold. * 07/16/96 Heat Transfer Heat is always transferred from hot to cold. Heat is transferred by conduction, convection, and radiation. *

KNOWLEDGE CHECK ____ is a measure of how quickly atoms are moving. A ____ measures the temperature of matter. The total amount of ____in an object is known as thermal energy. Which object has more thermal energy: Cup of coffee at 80°F or a bathtub filled with coffee at 60°F? KNOWLEDGE CHECK

TEMPERATURE is a measure of how quickly atoms are moving. A THERMOMETER measures the temperature of matter. The total amount of KINETIC ENERGY in an object is known as thermal energy. Which object has more thermal energy: Cup of coffee at 80°F or a bathtub filled with coffee at 60°F?BATHTUB = more particles, more energy KNOWLEDGE CHECK

TRANSFER of ENERGY

TRANSFER OF THERMAL ENERGY Thermal energy is always moving all around you. Thermal energy affects your life in very important ways. Changes in weather, cooking your food, and heating your house are a few of the ways the transfer of thermal energy helps us. TRANSFER OF THERMAL ENERGY

Conduction The transfer of heat by direct contact between objects or particles

Convection Heat transferred by the movement of molecules within a substance Movement occurs from warmer areas to cooler areas

Radiation Heat transferred through space in the form of waves EXAMPLE: The sun’s rays causing a sunburn

Helping or Slowing the Flow of Energy CONDUCTOR INSULATOR Conductors are materials that transfer heat easily. Examples: metals like copper and gold An insulator is a material that does not transfer heat easily. Examples: liquids and gases jacket Helping or Slowing the Flow of Energy

What examples of thermal energy and thermal energy transfer can you see around you right now? KNOWLEDGE CHECK

What examples of thermal energy and thermal energy transfer can you see around you right now? Microwave, sun = radiation Stove/pan, spoon in heated pot = conduction Air currents = convection KNOWLEDGE CHECK

MATTER and HEAT

MATTER and HEAT States of Matter Energy and Matter SOLID = particles are close together, move slow (vibration) LIQUID = particles spread apart, slide past each other GAS = particles move fastest, move everywhere (spread out) Solid = least amount of energy Liquid = medium energy Gas = most energy Energy is related to particle movement. MATTER and HEAT

PHASE CHANGE and ENERGY Phase changes occur when an objects state of matter change. In order for a change in phase to occur, energy must be either released or absorbed. Solid -> Liquid Melting Energy is absorbed. Liquid -> Solid Freezing Energy is released. Liquid -> Gas Vaporization Gas -> Liquid Condensation Solid -> Gas Sublimation PHASE CHANGE and ENERGY

Identify whether energy needs to be absorbed or released in the following scenarios: Ice cube melting Boiling water Dry ice placed in the air Dew forming on grass KNOWLEDGE CHECK

Identify whether energy needs to be absorbed or released in the following scenarios: Ice cube melting Released Boiling water Absorbed Dry Ice placed in the air Absorbed Dew forming on grass Released KNOWLEDGE CHECK