Please take your notebook out and take your hats off Science 14 and 10-4 with Mrs. Martin 5.5 Heat...
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Transcript of Please take your notebook out and take your hats off Science 14 and 10-4 with Mrs. Martin 5.5 Heat...
Please take your notebook out and take your hats off
Science 14 and 10-4with Mrs. Martin
5.5 Heat Transfer Technologies
Agenda
• Review • Notes on 5.5 Heat Transfer Technologies– Liquid coolant in engines– Refrigerators
• Videos
Review
Particle Model of Matter says:–All matter is made up of small
particles.–All particles are in constant motion.
What is this jiggling or vibrating motion called?
Review
• Brownian motion is the jiggling or vibrating of particles
• As the temperature increases what happens to the movement of the particles?
• Temperature is the average of all kinetic energies (motion).
Review Give an example of:
• Convection– hot liquid or gas rises
• Conduction – direct contact heat transfer
• Radiation– travels in rays or waves
Heat Transfer Technologies
• Convection ovens use a fan to move the air in convection currents
Getting Rid of the Heat
• Engines get hot because fuel combustion releases heat
• Vehicles need to remove heat to protect the engine
• If the engine doesn’t cool properly, it overheats and explodes like this: https://www.youtube.com/watch?v=w9dED6bNIpM
Video
Coolant• Heat is conducted from the engine to the liquid
coolant, which is pumped to the radiator
Radiator• Metal alloy is a good conductor• Heat from the liquid is conducted through this
alloy to the air• Either a fan or the motion of a vehicle forces
the heat from the radiator into the air
Extra time?
• Video on how an engine works and is cooled:– https://www.youtube.com/watch?v=V7inC4lOpGs – New technology
https://www.youtube.com/watch?v=xeYPR-v_9Ko
Evaporation
• When you sweat, it is so that the water can evaporate to cool your body
• Water absorbs the heat and removes it when it evaporates into the air
• Like liquid coolant in an engine, a refrigerator uses refrigerant as coolant.
• Coolant circulates through the pipes
Refrigeration
Heat from the hot food goes to the cold refrigerator air
• The coolant evaporates as it gets warmer • It is pumped to the compressor and is
converted back to a cool liquid• The heat is released to the room
How does leaving the fridge door make the room warmer?
What happens when cooling fails?
• What happens if the electricity goes out in a nuclear power plant?– https://www.youtube.com/watch?v=91JZCbGLCvk– (short on time go to 2:55-4:15)
• Nuclear reactor meltdown from cooling malfunction on the NEWS:– https://www.youtube.com/watch?v=ulO9LOQ0yis
Quick Quiz
#2 ___________
#1 ___________
#3 ___________