This is a lab report example about measuring the specific heat capacity of water. This lab report is a whole report starting from research question and ending with the conclusions and findings about the report.
Research Question
What is the specific heat capacity of water?
Introduction
The specific heat capacity is defined as the amount of thermal energy needed to increase the temperature of a mass of one kilogram of a substance by one degree.This can be stated by the following equation where Q is heat supplied to the substance, m is the mass of the substance, c is the specific heat capacity and is the change in temperature. Every substance has a different specific heat capacity
Aim
To measure the specific heat capacity of water
Hypothesis
The specific heat capacity of pure water is 4200 Jkg-1 K-1, but since I used tap water in my experiment, I expect the average value of my experiment to be bigger than the normal value.
Variables
Dependent Variables
In this experiment, the dependent variable is the change in temperature when water is heated.
Independent Variables
Time taken to heat water is the independent variable.
Constant Variables
The factors affecting the change in temperature shoult be constant in this experiment.
- The amount of water heated for different amount of time is kept the same.
- The power of the heater is kept same as the same kettle is used throughout the whole experiment.
Apparatus
- Stopwatch
- Tap water
- Thermometer
- Beaker
- Kettle
Method
- 0.5 L of tap water is measured with a graduated beaker.
- The kettle is filled with 0.5 L of tap water.
- The initial temperature of water in the kettle is measured and recorded.
- The water is heated for 30 seconds. Time is kept with the watch.
- The final temperature of the water is measured and recorded.
- The steps 1, 2, 3, 4 and 5 are repeated with time intervals of 50, 70 and 90 seconds respectively.
- After each time interval the water is renewed with the same amount of water.
Data Collection
Time intervals / seconds | The temperature / °C | ||
Initial | Final | Change in temperature | |
30 | 27 | 36 | 9 |
50 | 25 | 44 | 19 |
70 | 24 | 51 | 27 |
90 | 25 | 62 | 37 |
Presentation of the Data
Calculations
Q=M*C*DELTA T is used to determine the c values in the four trials. The kettle has a powe of 1000W. I have already calculated the mass of the water I used in the four trials by using graduated beakers. The mass of the water in all the four trials is 0,5L.
Conclusion and Evaluation
The mean value I got for the specific heat capacity of water is 5495 J kg^{-1 }°C^{-1}. As I stated in my hypothesis the value I got is bigger than the expected value because I used tap water instead of pure water and the impurities in tap water affected the specific heat capacity.
I would get more accurate results if I hadn’t done this experiment on my own. Because, I hold thermometer in my one hand and the stopwatch in the other, so I couldn’t manage to place the thermometer in the right place in water. Sometimes, the thermometer touched the bottom of the kettle and I think this affected my results.
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