# Science project By Dillon Williams And. Vocab Section 1 - Temperature of an object is a measure of the average kenetic energy of the particles in the.

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Science project By Dillon Williams And

Vocab Section 1 - Temperature of an object is a measure of the average kenetic energy of the particles in the object. - Thermal energy The sum of the kenetic and potentioal enerhy of all the particles in an object. - Heat is thermal energy that flows from something at a higher temperature to something at a lower temperature. - Specific heat is the amount of heat that is needed to raise the temperature of 1 kg of some material by 1°C Section 2 - Conduction is the transfer of thermal energy by collisions between particles in matter. - Convection is the transfer of thermal energy in a fluid by the movement of warmer and cooler fluid from place to place. - Radiation is the transfer of energy by electromagnetic waves. - Insulator is a material in which heat flows slowly. Section 3 -Solar Collector- absorb radiant energy from the sun -Thermodynamics the study of the relationship among thermal energy, heat, and work -first law of thermodynamics- increase of thermal energy in a system equals the work done on the system plus the heat transferred to the system -second law of thermodynamics-one way to state it is impossible for heat to flow from a cool object to a warmer object unless work is done -heat engine- device that converts heat into work -internal combustion engine- heat engine in a car in which fuel is burned inside the engine in chambers or cylinders

Self check sec.2 1. Explain why materials that are good conductors of heat are poor insulators. A. A conductor lets heat out or in very easily and an insulator is the opposite because it is supposed to keep energy in. 2. Explain why the air temperature near the ceiling of a room tends to be warmer than near the floor. A. The old saying goes hot air rises that's why its warmer because warmer air is less dense then cold air it gets pushed to the top of the room. 3. Predict whether plastic foam, which contains pockets of air, would be a good conductor or a good insulator. A. It would be a better insulator because the heat of the object would get trapped in the air pockets slowing down the heat from escaping. 4. Describe how a convection current occurs. A. convection current occurs when The heat from the light at the bottom of the lamp causes one fluid to expand more than the other. This creates convection currents in the lava lamp. 5. Think Critically Several days after a snowfall, the roofs of some homes on a street have almost no snow on them, while the roofs of other houses are still snow covered. Describe what would cause this difference. A. if the shingles are darker they attract more heat than if the shingles are lighter 1. Explain why materials that are good conductors of heat are poor insulators. A. A conductor lets heat out or in very easily and an insulator is the opposite because it is supposed to keep energy in. 2. Explain why the air temperature near the ceiling of a room tends to be warmer than near the floor. A. The old saying goes hot air rises that's why its warmer because warmer air is less dense then cold air it gets pushed to the top of the room. 3. Predict whether plastic foam, which contains pockets of air, would be a good conductor or a good insulator. A. It would be a better insulator because the heat of the object would get trapped in the air pockets slowing down the heat from escaping. 4. Describe how a convection current occurs. A. convection current occurs when The heat from the light at the bottom of the lamp causes one fluid to expand more than the other. This creates convection currents in the lava lamp. 5. Think Critically Several days after a snowfall, the roofs of some homes on a street have almost no snow on them, while the roofs of other houses are still snow covered. Describe what would cause this difference. A. if the shingles are darker they attract more heat than if the shingles are lighter

Self check sec.3 1. Explain how the thermal energy of a closed system changes with time. The thermal energy of a closed system changes with time when the system is worked enough. 2. Compare and contrast an active solar heating system with a radiator system. A solar collector absorbs radiant energy from the sun. The absorbed energy heats water in pipes just above the plate. A pump circulates hot water to radiators in rooms of the house. A solar collector and radiator work together, and they almost work the same. One of the only differences is that solar collectors don't heat the water to produce steam. 3. Explain whether or not a heat engine could be made 100 percent efficient by eliminating friction. It wouldn't because heat could not be completely converted into work. 4. Diagram how the thermal energy of the coolant changes as it flows in a refrigerator. The liquid coolant is pumped through an expansion valve and changes into a gas. When the coolant changes it cools. The cold gas is pumped through pipes inside the refrigerator, where is absorbs thermal energy. As a result the inside of the refrigerator cools. The gas then is pumped to a compressor that does work by compressing the gas. This makes the gas warmer than the temperature of the room. The warm gas is pumped through the condenser coils. Because the gas is warmer than the room, thermal energy flows form the gas to the room. Some of this heat is the thermal energy that the coolant gas absorbed from the inside of the refrigerator. As the gas gives of heat, it cools and changes to a liquid. The liquid coolant then is changed back to a gas, and the cycle repeats. 5. Think Critically Suppose you vigorously shake a bottle of fruit juice. Predict how the temperature of the juice will change. Explain your reasoning. The temperature of the juice would stay the same because the bottle prevents any transfer of energy by conduction or convection.

Applying Math sec. 1 pg. 162 The air in a living room has a mass of 72 kg and a specific heat of 1,010 J/(kg degrees C). What is the change in thermal energy of the air when it warms from 20 degrees C to 25 degrees C 1. Q m (Tf -Ti) C(72 kg) (25 degrees C - 20 degrees C) (1,010 J/kg degrees C) (72 kg) (5 degrees C) (1,010 J/kg degrees C) 363,000 J

Applying Math sec. 2 Calculate Solar Radiation Averaged over a year in the central United States, radiation from the sun transfers about 200 W to each square meter of Earth's surface. If energy falls on the house each second? 200W x 10=2000W Calculate Solar Radiation Averaged over a year in the central United States, radiation from the sun transfers about 200 W to each square meter of Earth's surface. If energy falls on the house each second? 200W x 10=2000W

Applying Math sec. 3 Calculate Change in Thermal Energy Your push down on a handle of a bicycle pump with a force of 20N. The handle moves 0.3 m, and the pump does not absorb or release any heat. what is the change in thermal energy of the bicycle pump? Thermal energy (20 N) (.3 m) = 6 J Calculate Work The thermal energy released when a gallon of gasoline is burned in a car's engine is 140 million J. If the engine is 25 percent efficient, how much work does it do when one gallon of gasoline is burned? Work (140,000,000 J) (25%) = 35,000,000 J Calculate Change in Thermal Energy Your push down on a handle of a bicycle pump with a force of 20N. The handle moves 0.3 m, and the pump does not absorb or release any heat. what is the change in thermal energy of the bicycle pump? Thermal energy (20 N) (.3 m) = 6 J Calculate Work The thermal energy released when a gallon of gasoline is burned in a car's engine is 140 million J. If the engine is 25 percent efficient, how much work does it do when one gallon of gasoline is burned? Work (140,000,000 J) (25%) = 35,000,000 J

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