In a previous article, we discussed some simple experiments that can be done to demonstrate heat conduction. Here, we continue our investigation into heat transfer experiments, but with a focus on convection and radiation.
A popular experiment involves a large transparent bowl or container of ice water. Combine hot water and a few drops of food coloring into a small transparent container, such as a perfume bottle. Place the small container inside of the bowl, and observe the convection currents.
Radiation experiments can be done by comparing how quickly dark, shiny, and white objects heat and cool. The heating source may be sunlight or a lamp or a similar radiation source. You will need something to record time with, and at least one thermometer.
a) Place the same amount of ice water into three bowls that are preferably made of the same material, such as plastic or ceramic. Obtain three different covers where one is black, one is white, and the other shiny. For example, colored paper and aluminum foil will suffice, and so will plastic bags. Cover or wrap the bowls with the materials. Place them outside when it is sunny or under the heat source for twenty to thirty minutes.
At least every five minutes record the temperature and the time. The water in the black container will heat up more quickly than the others.
The experiment can also be done using one bowl at a time and with one thermometer. Switch the bowl covering and change the water to compare how the water heats under different materials. You may substitute containers that are black, white, and shiny, instead of using covers. The containers should be as uniform as possible, and should be of the same material such as metal or plastic.
Graph the temperature versus time by placing the dependent variable temperature on the y-axis, and the independent variable time on the x-axis. Do this for every object. Compare your results.
b) Repeat the experiment, but this time fill the bowls with hot water and do not place them under a heat source. Record the amount of time it takes for the water to cool. The water in the black container should cool more quickly than the others.
Graph the temperature versus time by placing the dependent variable temperature on the y-axis, and the independent variable time on the x axis. Do this for every object. Compare your results.
Conceptual Physics by Paul Hewitt
Essential University Physics by Paul Wolfson
Fundamentals of Physics by Halliday, Resnick, and Walker
Cyclone Olaf In 2005 by Jacques Descloitres
Mars Thermal Emission NASA Jet Propulsion Lab