Presentation on theme: "Day Topic: Finish Convection, Begin Radiation"— Presentation transcript:
1Day 9 5.3.11 Topic: Finish Convection, Begin Radiation Obj: I can describe a draw a convection currentStarter: Explain how aradiator can heat a room.
2Convection (thru fluid) types ForcedFan behindheat sourceHeat SourceForcedNatural convectionFluids 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 convectionIn 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.
3Convection 27 or Conduction 24 EurekaConvection 27orConduction 24
4Convection (thru fluid/air) Land BreezeDAYOREVENINGSea Breeze
5Natural Convection Current Demo:“Shoe BoxHouse”Sketch Either image1st Floor2nd FloorWarm AirCool AirConclusion:As warm air rises and exits the house, cool air replaces the warm air which continues the convection current
8Thermal RadiationAll 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.
10Radiation: heat transfer in the form of electromagnetic waves, including light. Sketch this image.Reflects MOST RadiationAbsorbs MOST Radiation &Emits as Heat Energy
11Thermal RadiationColorsBlack 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.
12Solar RadiationRadiant Energy travels on waves through space on particles or pure energy. Radiation is a heating mechanism that takes place through electromagnetic waves.