Presentation on theme: "Energy Transfer and Interactions of Matter and Energy"— Presentation transcript:
1Energy Transfer and Interactions of Matter and Energy 6.P.3
2QuestionIf a cup of hot coffee and a red popsicle were left on the table in this room what would happen to them? Why?The cup of coffee will cool until it reaches room temperature. The popsicle will melt and then the liquid will warm to room temperature.
3In this lesson you will revisit: The way in which heat behaves.The energy transfer methods:conductionconvectionradiationHow to reduce heat losses from your home.
4Let’s Review: Measuring Heat Heat is measured with a thermometer. CelsiusFreezing: 0°Boiling: 100 °FahrenheitFreezing: 32 °Boiling: 212 °
5What Does Heating or Cooling Do to Materials? Melting: Solid matter changes its state to liquid.Freezing: Opposite process of melting is called freezing.Liquid matter loses heat and changes its state to solid.Boiling: Liquid matters gain heat and change their states to gas.
6Energy can be transferred from one system to another in different ways: Thermally: when a warmer object is in contact with a cooler oneMechanically: when two objects push or pull on each other over a distanceElectrically: when electrical source such as a battery or generator is connected in a complete circuit to an electrical deviceElectromagnetic Waves
7Molecules in Motion: Thermal energy The motion of molecules produces heatThe more motion, the more heat is generatedThermal energy is transferred through a material by the collisions of atoms within the material.
8Heat TransferThe movement of heat from a warmer object to a cooler one.Heat flows through materials or across space from warm objects to cooler objects, until both objects are at equilibrium (balanced).
9Heat Transfer Heat always moves from a warmer place to a cooler place. Hot objects in a cooler room will cool to room temperature after the hot object transfers some of their heat to the cold object.Cold objects in a warmer room will heat up to room temperature.
10Heat Transfer Cont.Therefore warm things lose heat and cool things gain heat until they are all at the same temperature.Example: Ice cube is put in a glass of warm water. Ice cube gains heat from the water and the warm water loses some heat.Eventually the ice will melt and the water will be at an even temperature
11Heat Transfer Methods Conduction Convection Radiation A warmer object can warm a cooler object by contact (close/touching) or at a distance (far away)ConductionConvectionRadiation
12ConductionConduction involves the transfer of heat through direct contactHeat travels through solids primarily by conduction.Over time, thermal energy tends to spread through a material and from one material to another if they are in contact (conduction)
13ConductionWhen you heat a metal strip at one end, the heat travels to the other end.As you heat the metal, the particles vibrate, these vibrations make the adjacent particles vibrate, and so on and so on, the vibrations are passed along the metal and so is the heat. We call this?Conduction
14ConvectionTakes place in liquids and gases as molecules move in currentsHeat rises and cool settles to the bottom.It continues in an up and down movement: warm rising and cool sinking (currents).These currents are in air, water, and other fluids
15Water movement Cools at the surface Convection current Hot water rises Cooler water sinks
16Where is the freezer compartment put in a fridge? Cold air sinksWhere is the freezer compartment put in a fridge?Freezer compartmentIt is warmer at the bottom, so this warmer air rises and a convection current is set up.It is put at the top, because cool air sinks, so it cools the food on the way down.
17Why are boilers placed beneath hot water tanks in people’s homes? Convection questionsWhy does hot air rise and cold air sink?Cool air is more dense than warm air, so the cool air ‘falls through’ the warm air.Why are boilers placed beneath hot water tanks in people’s homes?Hot water rises.So when the boiler heats the water, and the hot water rises, the water tank is filled with hot water.
18RadiationRadiation is energy that travels across distances in the form of electromagnetic waves.Heat is transferred through spaceEnergy from the sun being transferred to the EarthLight and other electromagnetic waves can warm objects.How much an object’s temperature increases depends on:how intense the light striking the surfacehow long the light shines on the objecthow much light is absorbed.
19? RADIATION How does heat energy get from the Sun to the Earth? There are no particles between the Sun and the Earth so it CANNOT travel by conduction or by convection.?
20The sun is a major source of energy for changes on the earth’s surface. The sun loses energy by emitting (releasing) light.A tiny fraction of the light reaches the earth, transferring energy from the sun to the earth.The sun’s energy arrives as light with a range of waves:Infrared Light: longer waveVisible Light: visible waveUltraviolet Light: shorter waveRadiation
21Radiation Radiation travels in straight lines True/False Radiation can travel through a vacuumRadiation requires particles to travelRadiation travels at the speed of light
23Why are houses painted white in hot countries? Radiation questionsWhy are houses painted white in hot countries?White reflects heat radiation and keeps the house cooler.Why are shiny foil blankets wrapped around marathon runners at the end of a race?The shiny metal reflects the heat radiation from the runner back in, this stops the runner getting cold.