2 What is Heat?? Heat = Thermal Energy!! Thermal Energy = the total energy of all of the particles in a material or object.Throughout the ages people have invented a variety of devices to help create and capture heat for use.
3 Topic 1: Using Energy from Heat What are some ways that we use heat?Cook foodWarm buildingsDry clothesWhat are some ways Thermal Energy has been used throughout history?
4 Development of Heat Technologies What heat technologies can you think of that have been developed through-out time? Why have they changed?Examples….
5 Devices to generate, transfer, control or remove heat Heat = Thermal energyCan you think of any examples of devices that generate, transfer, control or remove heat?
6 Topic 2: Measuring Temperature Thermometer: Mechanical or electrical device for measuring temperature. Early thermometer was invented by Galileo.Scale: A series of equally measured sections that are marked and numbered for use in measurement.
7 Celsius ScaleCelsius Scale: Most commonly used in Canada. Unit of temperature is called a degree. Based on the boiling and freezing points of water.Boiling Point: The temperature at which water boils. 100o C at sea level.Freezing Point: The temperature at which water freezes. 0o C at sea level.
8 Another Scale… Kelvin is another way of measuring temperature. Scientists use Kelvin to explain the behaviour of gases.“Absolute Zero” is measured in Kelvin – which is the coldest possible temperature0 Kelvin = -273 ºC
9 Right Device for the Job Each thermometer has a sensor – a material which is affected by changes in the environment (such as temperature)The sensor produces a signal (information about temperature, such as an electrical current) which affects a responder (a pointer, light or other mechanism that uses the signal in some way)
10 The ThermocoupleWires made up of two different metals are twisted together.When the wire tips are heated, a small electric current is generatedThe amount of current depends on the temperature.They can measure higher temperatures than thermometers.The electric current can be used to turn switches on or off if the temperature changes.Used in kilns, diesel engines and industrial furnaces
11 Bimetallic Strip Made of two different metals joined together When the strip is heated one metal expands more than the otherThus the strip coils more tightlyMovement of the strip can operate a switch that can control furnaces…commonly used in thermostats in homes
12 Your Brain…(extra) Your brain has its own temperature sensor. It monitors your own internal temperature. If the temperature outside changes, the sensor signals your brain to release chemicals that will help your body adjust to normal temperature (37°C)
13 ContinuedRecording Thermometer: A bimetallic strip connected to a writing device and paper which records temperature fluctuations over time.Infrared Thermogram: Records infrared radiation, (heat sensor) as different colors according to their temperature.
14 Topic 3: Particle Model of Matter, Temperature and Thermal Energy Reminder: matter is anything that takes up spaceThree most important ideas of the model:All substances are made of particles too small to seeThe particles are always in motionThe particles have space between them
15 When motion of particles increases – so does the temperature When motion of particles decreases – so does the temperatureTemperature indicates the average speed of particle motion in a substance
16 Glow Stick Demonstration What will happen to the glow stick when it is placed in hot water?What will happen to the glow stick when it is placed in cold water?
17 EnergyEnergy is the ability to do work – in other words to cause changeIn order for something to change, there must be a transfer of energy from one thing to anotherEx. Charged batteries run your iPod, dead batteries would not
18 Thermal Energy Energy associated with hot objects What gives off thermal energy?
19 What Energy is…and is not Energy is not a substance.It cannot be weighedIt does not take up spaceEnergy describes a conditionLaw of Conservation of Energy: Energy cannot be created or destroyed. It can only be transformed from one type to another or passed from one object to another
20 Temperature vs. Thermal Energy Temperature = A measure of the average energy of the particles in a material.Thermal Energy = The total energy of all the particles in a material.What is the difference??
21 Topic 4: Expansion and Contraction Contract: Decrease in volumeExpand: Increase in volumeTemperature changes cause things to expand and contractHeated – usually causes expansionCooled – usually causes contractionUsually more drastic in gases, then liquids then solids
22 Topic 5: The Particle Model and Changes of State Heat Capacity: Amount of thermal energy that warms or cools the object by one degree Celsius.Specific Heat Capacity: Amount of thermal energy that warms or cools one gram of a material by one degree Celsius.
24 Solids Solids have definite shape and volume Cannot be compressed into smaller objectsWhen solids are heated – they expandWhen solids are cooled – they contract
25 Liquids Liquids have definite volume but no shape Cannot be compressed (meaning if I have 1 litre of coke, I cannot make it fit into a pop can)When liquids are heated – they expandWhen liquids are cooled – they contract
26 Gases Have no definite shape or size Can be compressed When heated, gases – expandWhen cooled, gases - contract
28 Definitions: Define, in your notes, each of the following: Melt Freeze EvaporateCondenseSublimation
29 ContinuedEvaporative Cooling: A process in which the faster moving particles on the surface of a liquid evaporate and escape into the air, the slower ones are left behind creating a lower average kinetic energy (cooling it)Particles are more or less organized when they are hot or cold????
30 Phase ChangingDuring a change from solid to liquid or liquid to gas the average temperature does not change even though heat is being added, the name for the heat that is added is latent heat.
31 Topic 6: Transferring Energy There are 3 main ways to transfer energy1) Radiation2) Conduction3) Convection***See handout***
32 Transferring Energy Continued Energy Source: An object or material that can transfer its energy to other objects.Radiation: The transfer of energy without any movement of matter.Radiant Energy: (a.k.a. EMR) Energy that is transferred by radiation.
33 Radiant EnergyAll forms of radiant energy share several characteristics:- They behave like waves- They can be absorbed and reflected by objects- They travel across empty space at the same high speed of 300,000 km/s
34 Conduction and Insulation Thermal Conduction: The process of transferring thermal energy through direct collisions between particles.Examples of good conductors???Heat Insulators: Are very poor conductorsExamples???
35 Topic 7: Sources of Thermal Energy Energy appears in many formsPotential Energy: Stored energyE.g. elastic pulled back and ready to be shot.Kinetic Energy: Energy of motionExamples??
36 Chemical EnergyStored chemical energy is released in the form of thermal energy when it is burned.
37 Electrical Energy Electricity Example: hydro-electric dams – falling water is changed to electrical energy
38 Geothermal EnergyEnergy that we get from the Earth’s interior
40 Passive Solar HeatingUses materials in the structure to absorb, store, and release solar energy.Example: a wall of windows
41 Active Solar EnergyUses mechanical devices to distribute stored thermal energyExample: fansSolar Collectors – use stored water or air on the roof, heats it, and then pumps it through the building
42 Wind EnergyMoving airIs a result of solar energy – as the sun heats the air, the warmer air rises and cools off. Cooler air falls, creating a convection current – this forms wind
43 Fossil FuelsChemicals made from plants and animals that died and decomposed millions of years ago and have preserved deep underground.
44 Energy Converters Energy can be converted into another form. For example a candle can convert chemical energy into heat and light energy.Candles are energy converters (devices which convert or change energy from one form to another.)Other examples????
45 Renewable Resources Definition: Renewable resources are a natural resource that grow at about the same rate they are used up.
46 Non-Renewable Resource Definition:A resource which is limited in supply and cannot be replaced once it is used.
47 Renewable Resources in Alberta Examples:Trees (Forestry)Wind (Wind Farms)Agriculture ( One of the biggest crop producers in Canada)Water (Dams and water conservation)Solar ( Solar Panels and Solariums)
48 Non-Renewable Resources in Alberta Examples:Oil (Oil Wells)Natural Gas (Pipelines across the province)Coal (Mining in Alberta)
49 Positive and Negative Effects On Our Environment Positive (Renewable)PlentifulNon-pollutingLow cost to acquireCogenerationNegative (non-renewable)Polluting – greenhouse gases, thermal pollutionExpensiveCan be rareNot plentiful
50 Greenhouse Gases – do not write down Even though carbon dioxide occurs naturally in the environment (we breathe out CO2 and plants require CO2), it, like anything is only good in moderation. When there is too much CO2 in the air, heat from Earth is unable to escape into space because it is trapped by greenhouse gases (which have a lot of CO2 in them) – scientist believe that this leads to GLOBAL WARMING
51 Global Warming do not write down When there is an increase in CO2 and greenhouse gases are trapping thermal energy – the Earth’s temperature increases rapidly. A few degrees doesn’t seem to affect us much, but to the Earth, it can make a huge difference. It can change climate zones, plant growing abilities, dry up rivers and lakes, and even melt polar ice caps….What are some effects on the surrounding environments if these things happen?
52 CogenerationSometimes negative effects can be turned into more positive effects – cogeneration uses waste from thermal pollution to produce electricity or uses the waste to heat buildings.FACT: when fuel burns in a thermo-electric power plant, only about 1/3 of its energy is converted into electricity – cogeneration is efficient because it uses some of the remaining 2/3 of energy
53 The Three Important Renewable Resources to me and Why? Water: Very important to me since I need water to survive. Water is a very good way to generate energy so that I may have electricity in my home.Agriculture: It is the most important to me since I need food to live. It provides me with produce to eat and clothes that I may wear.
54 ContinuedSun: The sun gives me energy to go to school everyday. It provides me with light so that I am not always walking around in the dark. It also makes things grow. The best part is that you can capture the sun and turn it into energy that can be used.