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. 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 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 ◦ The total energy of the particles in a material ◦ Depends on temperature, mass, and type of substance A 80ºC Which beaker of water has more thermal energy? ◦ B - same temperature, more mass B 80ºC 400 mL 200 mL 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. Heat is transferred by conduction, convection, and radiation. 1. ____ is a measure of how quickly atoms are moving. 2. A ____ measures the temperature of matter. 3. The total amount of ____in an object is known as thermal energy. 4. Which object has more thermal energy: Cup of coffee at 80°F or a bathtub filled with coffee at 60°F? KNOWLEDGE CHECK 1. TEMPERATURE is a measure of how quickly atoms are moving. 2. A THERMOMETER measures the temperature of matter. 3. The total amount of KINETIC ENERGY in an object is known as thermal energy. 4. 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 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 The transfer of heat by direct contact between objects or particles Heat transferred by the movement of molecules within a substance Movement occurs from warmer areas to cooler areas Heat transferred through space in the form of waves EXAMPLE: The sun’s rays causing a sunburn CONDUCTOR INSULATOR Conductors are An insulator is a materials that material that does transfer heat not transfer heat easily. easily. Examples: Examples: ◦ liquids and gases ◦ metals like ◦ jacket copper and gold Helping or Slowing the Flow of Energy 1. What examples of thermal energy and thermal energy transfer can you see around you right now? KNOWLEDGE CHECK 1. 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 States of 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) Energy and Matter Solid = least amount of energy Liquid = medium energy Gas = most energy Energy is related to particle movement. MATTER and HEAT 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 ◦ Energy is absorbed. Gas -> Liquid ◦ Condensation ◦ Energy is released. Solid -> Gas ◦ Sublimation ◦ Energy is absorbed. PHASE CHANGE and ENERGY 1. 2. 3. 4. 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: 1. Ice cube melting Released 2. Boiling water Absorbed 3. Dry Ice placed in the air Absorbed 4. Dew forming on grass Released KNOWLEDGE CHECK