This experiment tested how the size of a container's mouth affects the cooling rate of water. The hypothesis was that a wider container mouth would allow for faster cooling as more water is exposed to air. Water samples were heated to 90°C then cooled in containers with small, medium, and large mouths. Temperature was recorded every minute, showing the large mouth cooled fastest at 3.67°C per minute, while the small cooled slowest at 2.5°C. However, inconsistent results for the large container made the data unreliable. Improved methodology and more accurate temperature readings are needed for future experiments.

1. Name: Sana Samad
Partners: Su Hong and Dong Hyun
Date of experiment: Wednesday September 29th 2010
Factors that affect the cooling rate of water
Aim: How can the size of the container’s mouth effect the cooling rate of water?
Hypothesis: Our hypothesis was that the wider the container’s mouth is the faster the water
will cool down. This was our hypothesis because if the container’s opening is large more
water is exposed to the air, whereas if the container is small less water is exposed to the air
and so it will be hard to cool down that amount of water.
Variables:
Input variable: Size of container’s mouth
Output variable: temperature of water every minute
Control variables:
Control variable 1: Amount of water: I will keep it constant by using the
same amount of water for the different beakers.
Control variable 2: Size of container: I will keep it constant by using the
same size of container
Control variable 3: Starting temperature of water: I will keep it constant by
having the same 90 degrees starting temperature of water for all
the beakers
Control variable 4: Material of container: I will keep it constant by using the
same type of material.
Materials:
• 1 Bunsen burner
• 1 thermometer
• 1 100ml beaker
• 1250ml beaker
• 1 500ml beaker
• 1 stop watch
• 1 retort stand
• 1 clamp
• 1 boss head
• 1 gauze mat
• 1 tripod
• 1 lighter

2. • 1 heat mat
Diagram:
This is an image of how
experiment looked like. We
had the retort stand and the
clamp, which was holding
the thermometer in the
small beaker with 100 ml of
water. The Bunsen burner
is underneath the tripod and
gauze mat, which was used
to heat up the water up to
90 degrees.
Method:
1. Set up equipment as shown in diagram 1.
2. Light the Bunsen burner
3. Put the small beaker on the gauze mat
4. Heat the water in the small beaker till 90 degrees Celsius
5. Switch of the Bunsen burner
6. Measure the temperature of water
7. Record the temperature of water every minute till you have 12 readings
8. Follow the same instructions for medium beaker and large beaker
Results:

3. SMALL BEAKER MEDIUM BEAKER
Time Temperatures Time Temperatures
(Minutes) (Degrees Celsius) (Minutes) (Degrees Celsius)
0 90 0 90
1 87 1 85
2 83 2 80
3 80 3 74
4 77 4 72
5 75 5 68
6 73 6 66
7 69 7 64
8 67 8 62
9 65 9 59.5
10 63 10 57
11 62 11 55
12 60 12 54.5
LARGE BEAKER
Time Temperatures
(Minutes) (Degrees Celsius)
0 90
1 85
2 76
3 73
4 67
5 65
6 61.5
7 58
8 56
9 54
10 52.5
11 50
12 48

4. Conclusion:
If you look at our data tables for the three different beakers you can see that the
beaker with the largest mouth had the water cooled down the quickest. This was because the
beaker had a large mouth and so more water was exposed to the air for cooling it down
whereas for the medium and small beaker their mouth was not big enough and so the water
took a bit long to cool down. The data table for the waters temperature in the small beaker
decreased an average of 2.5 degrees each minute, for the medium beaker the waters
temperature decreased every 2.96 degrees and for the large beaker it decreased 3.67 degrees
every minute. Our hypothesis was proven right. The larger the container’s mouth was the
faster the water cooled down
I think that the data we have collected in this experiment is not that reliable because
for the small beaker the results were pretty consistent, for the medium beaker there was a
jump where there was a difference of 5 degrees but the for the large beaker one of the
difference between the temperature of water was 11 degrees. That was a bit shocking and I
think that was because we were not very accurate in our readings of the temperature.
Sometimes when we use to heat up the water, we use to loose track of the time and
the water would heat up till 92 degrees instead of 90 degrees and that was a bit hard to
maintain. At the end our hypothesis was right the larger the containers mouth the faster the
water-cools down.
Evaluation:
I think our method was reliable because we specifically noted down every step that
would be taken in order to do this experiment. Most of the results that we got from our
experiment could be trusted but I would not call them reliable because the results we got
from the large beaker had inconsistent differences. Some of the things that could be
improved would be that from next time we could start reading the temperature of the water
before the minute occurred, because sometimes the temperature was still decreasing and we
recorded it. Another difficulty was that since the clamp was in our way we could not see the
thermometer’s number clearly and so we had to adjust it during our experiment was going
on, which is why sometimes the thermometer was lifted from the water and so it was exposed
to the air, and because of that the temperature went down quickly. So then by the time we put
the thermometer back, the temperature was a bit messed-up. Thus from next we should try
doing it carefully. One of the strengths of this experiment was that we as a group were
prepared, we all did our jobs like recording, using the stop-watch, setting-up equipment and
all of us had down that well.