Transfer of Energy

Today… Makes you think (5 min) Writing questions (20 min) Notes on Radiation (20 min)

Makes you think…. Watch the clip about Leonardo DiCaprio’s understanding of chinooks.Leonardo DiCaprio’schinooks What questions does it make you ask? Write them on the sticky notes at your table…

Makes you think…. On your whiteboard, answer the following question: Show your work! What is the amount of thermal energy in a 25 g popsicle that has a heat capacity of 2.34 J/g  O C and increases in temperature by 17 O C? Is the popsicle gaining or losing energy?

Makes you think…. On your whiteboard, draw the following diagram… Label the solid, liquid and gas phases on the diagram. What are 5 things happening at 100 O C?

Makes you think…. On your whiteboard, draw the following diagram… Label the solid, liquid and gas phases on the diagram. What are 5 things happening at 100 O C?

Expansion Let’s explore what happens to substances when we add or remove energy… P (solid, liquid, gas) Applications ie. Thermostats, cracks in pavement, liquids? Why is water unique? Expand when frozen, 4 0 C in lakes,

Expansion When particles move faster and apart and usually result in the substance getting bigger.

Contraction When particles move slower and get closer together making the substance get smaller.

Expansion and Contraction in Solids Solids can become longer or shorter depending on the temperature (average energy of the particles). Most solids expand or contract, at different rates, at different temperatures, depending on the type of substance. YDNHTWTD

Expansion and Contraction in Gases When the particles in a gas are heated, their average energy increases and they need more room, so they expand. When the particles in a gas are cooled their volume decreases, or contracts, because the particles need less room. plasma Under extremely high temperature conditions (like the temperatures inside the Sun), particles can be split into what makes them up - electrons and ions. This creates a fourth state of matter called plasma. YDNHTWTD

Expansion and Contraction in Liquids When the particles in a liquid are heated, their average energy increases and they need more room, so they expand. When the particles in a liquid are cooled their volume decreases, or contracts, because the particles need less room. the bore This is demonstrated by the liquid used in a thermometer. As the liquid expands and contracts, it moves up and down the inside tubing ( the bore ) of the thermometer. YDNHTWTD

What about water? When most liquid particles lose energy, they get closer together and form a solid (freezing). However, when water particles lose energy, they don’t actually get closer together when they form a solid. Please click the following word to watch a video on this….Whaaat? Please click the following word to watch a video on this….Whaaat? YDNHTWTD

Expansion/Contraction Mini Lab We will be manipulating the type of substance and the amount of heat.

Energy can be transferred in three ways.

Questions about Radiation? Sort the questions about radiation at your table into weak and powerful questions. Be ready to defend your answers. YDNHTWTD

Questions about Radiation? What is radiation? What is it for? How does it work? What affects radiation? YDNHTWTD

Questions about Radiation? What is the definition of radiation? How do humans use radiation to make their life better? How does radiation transfer heat? What controls the amount of radiation that an object absorbs? Is there a way to reflect the radiation so an object doesn’t absorb the heat? YDNHTWTD

Criteria of a Powerful Question YDNHTWTD Intention/Purpose of the Question: Gather information Ask for clarification Curiosity

Criteria of a Powerful Question YDNHTWTD In order to be respectful and taken seriously, your question should: Be spoken clearly Be specific Be thought out ahead of time

Questions for Monica Kohlhammer – Director of Planning YDNHTWTD Remember, we are gathering information to guide your design of your section of the New School. What information are you going to need?

Questions for Monica Kohlhammer – Director of Planning YDNHTWTD Write a few questions on a sticky note. Share your questions with another group. What are good qualities of the question? What are suggestions to improve the question?

#1 Radiation Radiant energy Radiant energy travels in waves. These waves can travel through space, air, glass and many other materials.

#1 Radiation radio waves, microwaves, visible light and X-rays There are different forms of EMR (electromagnetic radiation), including radio waves, microwaves, visible light and X-rays.

#1 Radiation radio waves, microwaves, visible light and X- rays There are different forms of EMR, including radio waves, microwaves, visible light and X- rays. You do not have to draw the above diagram.

#1 Radiation infrared radiation‘ heat radiation If the energy source is a warm object, like the sun, some of the thermal energy is transferred as a type of EMR called infrared radiation (IR) or ‘ heat radiation'.

#1 Radiation Properties (characteristics) of Radiant Energy Waves of radiant energy can travel in a vacuum.

#1 Radiation Properties (characteristics) of Radiant Energy Waves of radiant energy can travel in a vacuum. All waves travel, across empty space, at an extremely 300 Million m/s high speed (300 Million m/s).

#1 Radiation Properties (characteristics) of Radiant Energy Waves of radiant energy can travel in a vacuum. All waves travel, across empty space, at an extremely 300 Million m/s high speed (300 Million m/s). Radiant energy travels in a straight line.

#1 Radiation Properties (characteristics) of Radiant Energy Waves of radiant energy can travel in a vacuum. All waves travel, across empty space, at an extremely 300 Million m/s high speed (300 Million m/s). Radiant energy travels in a straight line. Radiant energy behaves like waves. Radiant energy can be absorbed and reflected by objects.

#1 Radiation  Reflection  Reflection occurs if the radiant energy cannot penetrate the surface of the material it comes into contact with.

#1 Radiation  Reflection  Reflection occurs if the radiant energy cannot penetrate the surface of the material it comes into contact with.  Absorption  Absorption occurs if the radiant energy penetrates part way into the object.

#1 Radiation  Reflection  Reflection occurs if the radiant energy cannot penetrate the surface of the material it comes into contact with.  Absorption  Absorption occurs if the radiant energy penetrates part way into the object.  Transmission  Transmission occurs if the energy penetrates completely, passing through the object with no absorption of energy.

#1 Radiation Absorbing / Emitting Energy Dull, dark Dull, dark objects absorb radiant energy when they are cool, and emit radiant energy when they are hot. (eg. asphalt sidewalk) Light, shiny Light, shiny objects or surfaces do not absorb radiant energy readily and do not emit radiant energy readily. (eg. ice surface)

#1 Radiation Absorbing / Emitting Energy Radiant emission of energy from the body depends on surface area (smaller areas help to retain heat, whereas, larger areas radiate heat).

#1 Radiation Desert Animals Killer Whales Polar Bear The desert animals have large ears to allow heat to escape the body readily and light colorings to reflect most of the radiant energy away from them, keeping them cooler. The killer whale's fusiform body shape and reduced limb size decreases the amount of surface area exposed to the external environment. This helps killer whales conserve body heat.) The polar bear’s black skin absorbs radiant energy with transparent hair, transmitting ultraviolet radiation to the skin. You do not have to write down all of the above descriptions, just make note of the example. This is evident in the adaptations of many species of animals who have successfully adapted to their environments.

#1 Radiation Radiation in the Environment radon Radiation is a natural part of our environment. Most radiation (82%) people are exposed to, comes from natural sources. Humans have always lived on earth in the presence of radiation. Natural radiation reaches earth from outer space and continuously radiates from the rocks, soil, and water on the earth. Background radiation is that which is naturally and inevitably present in our environment. Levels of this can vary greatly. People living in granite areas or on mineralized sands receive more terrestrial radiation than others, while people living or working at high altitudes receive more cosmic radiation. By far the largest source is radon, an odorless, colorless gas given off by natural radium in the Earth's crust. Artificial radiation, mostly from medical uses and consumer products, accounts for about eighteen percent of our total exposure. The nuclear industry is responsible for less than one percent. Radiation can be detected, measured and controlled. radioactivity The measurement of radiation is by the amount of radioactivity present or the amount of radiant energy given off. You do not have to write the above notes.

#2 Conduction Conduction, Energy Through Solids In solids, where the particles are closely packed together, thermal energy can be transferred from one particle to another very easily.

#2 Conduction Thermal conduction direct collisions Thermal conduction is the process of transferring thermal energy by the direct collisions of the particles. The space between the particles, in different solids, determines how quickly these collisions can take place.

#2 Conduction Good conductors Good conductors are those materials where there is little space between the particles that make up the material - like most metals. Poor conductors Poor conductors, like glass and wood are called heat insulators. These insulators when wrapped around an object slow down the rate of thermal conduction.

#2 Conduction Examples…Diamonds Hot and Cold packs Cooking

#3 Convection Convection: Convection: the circular motion of the particles, called convection.

#3 Convection Convection: Convection: the circular motion of the particles, called convection. convection current In convection, the warmer particles transfer their energy to the cooler particles as they move in a circular pattern, called a convection current. Lava lamps…mantle of the earth…weather

Transfer of Energy All energy systems have five common features: Energy Source Energy Source - this is where the energy comes from that can be transferred throughout the energy system. The energy source can be mechanical, chemical, radiant, nuclear or electrical. Direction of Energy Transfer Direction of Energy Transfer - energy is always transferred away from the concentrated sources. Changes in non-living systems spread out the energy evenly. Transformations Transformations - energy can change its form when it is transferred Waste Heat Waste Heat - almost all of the energy is transferred directly from particle to particle, but some of the energy can be lost to the surroundings. Control Systems Control Systems - a control device can start and stop the transfer of energy (a thermostat in a home heating system)

Next steps - energy sources - project and presentations - one more quiz - unit exam, review questions

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