The hypothesis is that is does, and the higher temperature water has, the faster the evaporation will be because the particles will gain more kinetic energy and therefore will more easily get to the speed at which it can escape from the liquid and turn into vapour. For example, when water is spilled, it dries off faster in warm weathers than in cold weathers.
The variables:
Dependent variable:
- The time it takes for 20ml of water to evaporate.
Independent variable:
- The temperature of the water in degrees Celsius.
Controlled variables:
- The volume of the container;
- The amount of water inside the container;
- The shape of the container;
- The material of the container
- The surface area or the water.
Uncontrollable variables:
- When water stays at a stable temperature.
- Airflow in the room
- Room temperature is not completely kept constant.
There will be errors because we measure the water temperature after heated by the heater. Measurements might be taken too early while the water is still being heated and temperature is still rising. That way the results will not be accurate. In order to reduce that error, temperature of the water will be only taken when the reading on the thermometer to 1 decimal place does not change in 5 minutes.
Airflow in the room cannot be completely controlled, we try to reduce this error by setting the experiment away from doors and windows and by turning off the air conditioner during the process of the experiment.
In order to lessen the unstable room temperature to affect the experiment, we try to keep the setting of the experiment as isolated as possible, away from heaters. And we make sure that the room temperature is the same as the temperature outside.
Equipment list:
1 Thermometer (±0.2˚C)
1 beaker with a capacity of 100ml (±5ml)
100 ml of water
1 stopwatch (±0.5s)
1 heater
1 steel stand
There should be indication lines on the beaker that shows us the difference of 20ml of water that was evaporated.
The heater must be flat and able to hold the beaker.
Diagram:
The experiment:
- A thermometer will be placed in the beaker vertically held by a steel stand. The end of the thermometer will not touch the sides of the beaker. Then water will be poured in, the water level should reach the line indicating 100ml.
- A heater will be placed under the beaker, the beaker should be completely supported by the heater.
- The temperature of the water will be first taken, with the heater turned off and the time it takes for 20ml of water will be recorded.
- After that, the water level will be filled back to 100ml. The same beaker should be used each time.
- Then the heater will be turned on and put at 20˚C, the second measurements will be taken once the water temperature becomes stable. Again, the temperature of water and the time taken for 20ml of water to evaporate will be recorded.
- After that, the heater will be turned 5˚C higher, at 25˚C. And the same procedure will be repeated at 30˚C, 35˚C, 40˚C, 45˚C, 50˚C, 55˚C, 60˚C (10 different temperature measurements altogether).
- This experiment will be repeated 3 times.
In this experiment there are some risks of getting burned by the heater towards the last measurements if the experiment is not done carefully. There are no other risks or dangers of procedure.
The range independent variable (temperature change) is according to the heater. The heater’s temperature will be raised by 5˚C for each measurements. As the procedure is repeated 10 times, the range temperature or the heater will change by 50˚C.