Heat transfer!

Our second experiment was about investigating the heat transfer of water in an unpainted and painted (black) aluminum cans. We did two activities: one for cooling and another one for heating. The latter part was supposed to be an additional experiment, but we still had enough time to do it. :)

I. Heat Transfer for Cooling

We heated water until it temperature almost reach its boiling point. Then, we measured them to 200mL using graduated cylinders and transferred the water onto each can. Using Thermo Sensors and LabQuest, we recorded the temperature in the water inside both cans as they cool down in room temperature.

The graph we got was curved. After further analysis, we concluded that the rate of cooling is directly proportional to the temperature difference inside and outside the can. It was also observed from their polynomial trendlines of degree 2, that the unpainted can cools faster.


II. Heat Transfer for Heating

Each can was then replaced with tap water of the same volume. We then placed them in front of an incandescent lamp. Using the same device, we plot the temperature of each can for 20 minutes. The result came out with a linear a graph, which means that the rate of change in temperature in both cans is constant. By looking at the last temperature recorded, it was obvious that the aluminum can painted in black became hotter than the unpainted one. Computing for the slope of the graphs using trendlines, we also saw that the black can heats faster.

III. Personal Insights
For this experiment, it was sort of a test of patience - waiting for 20 minutes for two cans heated by a lamp. T'was kinda funny how we spent our time while waiting for them:

yeap, we're bored :p

However, putting the almost-boiling-water-it-hurts-when-it-touches you was a challenge, especially when the pot holders are kinda tearing off. :)) Over-all, we had good results and fun lab class by trying to capture people's faces (haha!)