How is it that when you face a campfire at night, the front of your body can be uncomfortably hot while your back is cold?
- The camp fire emits heat in three different modes which are conduction, convection, and radiation. Each of these modes emits different levels of heat. The radiation part is what warms your body. The reason your back feels cold is because the fire is horizontally radiating heat outwards towards the part of our body that is the closest to it. The back would be really cold because it is not getting any of this radiating heat.
You can reach into a 400oF conventional oven and pull out a sheet of hot aluminum foil with your bare hands without being injured. How can this be?
- The reason for this is because aluminum foil has a very low heat index. This means that it heats up and cools down very fast. The aluminum foil is very thin which allows it to lose and gain heat fast.
Why does the interior of a car get extremely hot when parked in the sun on a hot sunny day?
- The interior of the car on a hot sunny day gets hot because the car receives thermal radiation from the sun. The car absorbs the thermal radiation, and then conduction transfers the exterior surface to the interior surface. The interior will receive direct radiation from the sun shinning through the windows which also heats the interior up. The heated interior surfaces of the car change the air temperature through convection. The color of the outside and inside of the car can vary the temperature significantly.
Here are links that relate to Unit 4 that explain Conduction, Convection, and Radiation in more depth.
https://www.vox.com/2016/7/20/12212472/what-is-fire
https://sciencing.com/tinfoil-experiments-12941.html
http://alkisites.vansd.org/dgray/Assignments/conduction_convection_radiation_reading.pdf
