Feyza Selçuk
9-C
İHSAN DOĞRAMACI FOUNDATION
BİLKENT ERZURUM LABORATORY SCHOOL
2nd Semester
2011-2012 Academic Year
9th Grade Physics
LAB REPORT
Name: Feyza Selçuk
Topic: Specific Heat Capacity of Normal Tap Water
1
Feyza Selçuk
9-C
Research Question: Specific heat capacity of pure water is known as 4200 J/(kgoC). But
what is the specific heat capacity of normal tap water?
Hypothesis: In my opinion, normal tap water will have a different specific heat capacity
than water because it is not pure.
Introduction:
The specific heat capacity of a solid or liquid is defined as the heat required raising unit mass
of substance by one degree of temperature. It is Formula is:
𝑒𝑛𝑒𝑟𝑔𝑦 𝑡𝑟𝑎𝑛𝑠𝑓𝑒𝑟𝑟𝑒𝑑 = 𝑚𝑐∆𝑇
Where m is mass of substance, c is specific heat capacity, and ∆𝑇 is change in temperature.
The aim of this experiment is to find the specific heat capacity of normal tap water.
To find the energy transferred, this formula can be used:
𝑝𝑜𝑤𝑒𝑟:
𝑒𝑛𝑒𝑟𝑔𝑦
𝑡𝑖𝑚𝑒
where power is known as 1000 W. (the kettle which is used to heat the water in experiment
has 1000 W rating)
2
Feyza Selçuk
9-C
Experimental Setup:
Before start to the experiment, area of experiment, equipments and safety should be
controlled.
List of Equipment:
 Kettle (1⁄2 liter capacity, 1000 W rating)
 Thermometer
 Stopwatch
 Tap water (1⁄2 kg)
To get more reliable results, the experiment should be repeated at least 4 times (or more.)
For each experiment, make sure that all items are ready.
Procedure to Follow:
 Firstly, prepare the apparatus needed during the experiment.
 Fill the kettle with water. Make sure that it is ½ kg.
 Then, measure the temperature of water before heating it, and record.

Monitor time by using stopwatch. Make sure that the water does not boil to prevent
evaporating.

After some time, measure the temperature of hot water and record it again.

Repeat these procedures for 4 times and for the each repetition, determine a different
time.

Decide a temperature and heat water until it reaches this target. Measure the times
passed. (to get more reliable result.)

Last, use your recorded data to calculate the specific heat capacity.
3
Feyza Selçuk
9-C
Data:
First Experiment:
Time:
0 second
45th second
Temp.:
26oC
44 oC
∆𝑡𝑖𝑚𝑒
45s
18oC
∆𝑇
The specific heat capacity of tap water found in this experiment is:
𝑒𝑛𝑒𝑟𝑔𝑦 𝑡𝑟𝑎𝑛𝑠𝑓𝑒𝑟𝑟𝑒𝑑 = 𝑚𝑐∆𝑇
𝑝𝑜𝑤𝑒𝑟 =
𝑒𝑛𝑒𝑟𝑔𝑦
𝑡𝑖𝑚𝑒
1000 W= energy/45s
Energy = 45 000 J
45 000 J = ½ kg x c x 18oC
c = 5000 J/kg oC
Second Experiment:
Time:
Temp.:
0 second
60th second
17 oC
41 oC
∆𝑡𝑖𝑚𝑒
60s
24oC
∆𝑇
4
Feyza Selçuk
9-C
The specific heat capacity of tap water found in this experiment is:
𝑒𝑛𝑒𝑟𝑔𝑦 𝑡𝑟𝑎𝑛𝑠𝑓𝑒𝑟𝑟𝑒𝑑 = 𝑚𝑐∆𝑇
𝑝𝑜𝑤𝑒𝑟 =
𝑒𝑛𝑒𝑟𝑔𝑦
𝑡𝑖𝑚𝑒
1000 W= energy/60s
Energy = 60 000 J
60 000 J = ½ kg x c x 24oC
c = 5000 J/kg oC
Third Experiment:
Time:
Temp:
0 second
75th second
13 oC
47 oC
∆𝑡𝑖𝑚𝑒
75s
34oC
∆𝑇
The specific heat capacity of tap water found in this experiment is:
𝑒𝑛𝑒𝑟𝑔𝑦 𝑡𝑟𝑎𝑛𝑠𝑓𝑒𝑟𝑟𝑒𝑑 = 𝑚𝑐∆𝑇
𝑝𝑜𝑤𝑒𝑟 =
1000 W= energy/75s
5
𝑒𝑛𝑒𝑟𝑔𝑦
𝑡𝑖𝑚𝑒
Feyza Selçuk
9-C
Energy = 75 000 J
75 000 J = ½ kg x c x 34oC
C = 4411 J/kg oC (approximately)
Fourth Experiment:
Time:
Temp:
0 second
90th second
19 oC
56oC
∆𝑡𝑖𝑚𝑒
90s
37oC
∆𝑇
The specific heat capacity of tap water found in this experiment is:
𝑒𝑛𝑒𝑟𝑔𝑦 𝑡𝑟𝑎𝑛𝑠𝑓𝑒𝑟𝑟𝑒𝑑 = 𝑚𝑐∆𝑇
𝑝𝑜𝑤𝑒𝑟 =
1000 W= energy/90s
Energy = 90 000 J
90 000 J = ½ kg x c x 37oC
c = 4864 J/kg oC (approximately)
6
𝑒𝑛𝑒𝑟𝑔𝑦
𝑡𝑖𝑚𝑒
Feyza Selçuk
9-C
Fifth Experiment:
Time:
Temp:
0 second
166th second
12oC
80 oC
∆𝑡𝑖𝑚𝑒
166s
∆𝑇
68oC
The specific heat capacity of tap water found in this experiment is:
𝑒𝑛𝑒𝑟𝑔𝑦 𝑡𝑟𝑎𝑛𝑠𝑓𝑒𝑟𝑟𝑒𝑑 = 𝑚𝑐∆𝑇
𝑝𝑜𝑤𝑒𝑟 =
𝑒𝑛𝑒𝑟𝑔𝑦
𝑡𝑖𝑚𝑒
1000 W= energy/166s
Energy = 166 000 J
166 000 J = ½ kg x c x 68oC
c = 4882 J/kg oC
Data Result:
Experiment:
Specific Heat Capacity Found: (J/kg oC)
1st (for ∆T of 18oC)
5000 J/kg oC
2nd (for ∆T of 24oC)
5000 J/kg oC
3rd (for ∆T of 34oC)
4411 J/kg oC
4th (for ∆T of 37oC)
4864 J/kg oC
5th (for ∆T of 68oC)
4882 J/kg oC
7
Feyza Selçuk
9-C
According to these experiments, average specific heat capacity of tap water found is:
4831 J/kg oC.
Conclusion and Evaluation:
As a conclusion, we see the result is different from the specific heat capacity of pure
water. Because tap water is not pure and it contains some other additives, its specific heat
capacity is different. During the experiment, volume of water should be kept constant to get
more reliable result because in this experiment time is our changeable factor. So change in
volume of water would cause unreliable results. The other important thing is using kettle
instead of Bunsen burner. If we used Bunsen burner, then the experiment would not be done
fairly because we cannot provide the same conditionals for each repetition. Also, we make
sure that thermometer just touches to water molecules because to get just water temperature,
thermometer should be used very carefully. In other ways, thermometer will give us different
results. To get more reliable result, this experiment can be re-done but by changing constant
and independent values such as volume of water and time.
In this experiment, average specific heat capacity of tap water is 4831 J/kg oC but by
eliminating human errors and using more precise measuring techniques, we will be able to get
more accurate and more consistent readings.
8