# Day Topic: Finish Convection, Begin Radiation

## Presentation on theme: "Day Topic: Finish Convection, Begin Radiation"— Presentation transcript:

Day 9 5.3.11 Topic: Finish Convection, Begin Radiation
Obj: I can describe a draw a convection current Starter: Explain how a radiator can heat a room.

Convection (thru fluid) types
Forced Fan behind heat source Heat Source Forced Natural convection Fluids expand when they heat up. In a container (or environment), warmer fluid floats to the top and cooler fluid sinks to the bottom. This is called natural convection. Forced convection In many houses a furnace heats air and then circulates the air to rooms. Since the heat is being forced through the system (with blowers) and circulating with other air, this is another example of convection. However, since the air is forced to flow by the blowers or fans, this is called forced convection.

Convection 27 or Conduction 24
Eureka Convection 27 or Conduction 24

Convection (thru fluid/air)
Land Breeze DAY OR EVENING Sea Breeze

Natural Convection Current
Demo: “Shoe Box House” Sketch Either image 1st Floor 2nd Floor Warm Air Cool Air Conclusion: As warm air rises and exits the house, cool air replaces the warm air which continues the convection current

Ball & Ring Demonstration

Thermal Radiation All objects with a temperature above absolute zero (-273 °C or -459 °F) emit thermal radiation. To emit means to give off. Thermal radiation comes from the thermal energy of atoms. Thermal radiation is also absorbed by objects. An object constantly receives thermal radiation, otherwise all objects would eventually cool down to absolute zero. Three identical aluminum bottles were spray painted and set in the window. Predict the temperature of the fluid inside of each bottle using the oC. Justify your response.

Eureka 29 Thermal Radiation

Radiation: heat transfer in the form of electromagnetic waves, including light.
Sketch this image. Reflects MOST Radiation Absorbs MOST Radiation & Emits as Heat Energy

Thermal Radiation Colors Black asphalt pavement gets very hot in the summer sun because it effectively absorbs thermal radiation. A silver mirror surface reflects most thermal radiation, while absorbing very little.

Solar Radiation Radiant Energy travels on waves through space on particles or pure energy. Radiation is a heating mechanism that takes place through electromagnetic waves.