I took readings all day from about 8:30am
to around 3:30pm every ten seconds.
The sensors collected about 2,500 readings
I did my experiments in December, February
& March as these are the hottest months of the school year.
Once my data collecting was finished for
the day, I plugged the sensors into a desktop computer and all the
readings were uploaded into Microsoft Excel.
I then used the Chart wizard to display
the data in a line graph. I also used Excel to work out the maximum,
minimum, and average temperatures.
Maximum Temperature 75oC
Minimum Temperature 15oC
Average Temperature 30oC
I found out that our lunches were being kept in
the Danger Zone (between 15 - 45oC) for a few hours a day!
I then needed to know what was causing the
heat. So I put, just sticking out of my bag, an infra-red light sensor.
Infra-red is a type of heat energy. I noticed that the heat inside my
lunchbox followed the Infra-red heat energy better than the outside air
I found out that it was the direct sun
light that was making the heat so intense. The heat from the outside
air and the lunchbox sort of follows the pattern that the infra-red
I discovered that while the outside air
did warm up the lunch box, it was the infra-red heat energy from being
in the direct sunlight that had the greatest affect on the temperature
of the lunchbox. My food was in the Danger Zone for quite a few hours.
I noticed that in the summer my school
lunch had gotten to a rather high temperature, whereas in the winter, I
had never had a problem like this.
Also, now my bag is in a Cloak bay, I can
take sandwiches, cake, or even yogurts to school without them getting
soggy or sour.
I think this is because my bag is not in
direct sunlight, so it is not getting affected by its infra-red heat