Investigate the relationship between temperature and evaporation rate.

5. Repeat steps 1 – 4 for the other liquid

6. Repeat steps 1 – 5 two times (time constraint)  

Data Collection

“Data shows the relationship between temperature and evaporation rate”

The calculation:

There is no calculation required in this experiment

Test 1:

Test 2:

The results support my hypothesis which is the higher the temperature, the more temperature will be lost when heated (dried), results in an overall drop in temperature in the boiling liquid. As for the cool liquid, the temperature is gained as heated (this is not stated above at the hypothesis) but has shown a very contrasting pattern (will be further discussed in the conclusion section).

The below graphs indicate the rate of change during the six minutes for the two tests for both cool and boiling liquids (water).

The graph indicates the boiling effect (drying – heating) on boiling liquid. For both tests, the temperatures for the liquid go down. At the first two minutes, it is notified that the temperature falls most severely. The explanation is that the molecules with kinetic energy are able to vibrate quickly and vigorously, as they hit the surface they evaporate, leaving the cooler (slower) molecules on the surface. There is a steady and consistent drop in temperature with no anomaly in both experiments. This reduction in temperature also proves that water absorbs latent heat from the surrounding when it evaporates causing evaporative cooling. This also proves high degree of accuracy.

The graph indicates the boiling effect (drying – heating) on cool liquid. For both tests, the temperatures for the liquid go up. At the first two minutes, it is notified that the temperature increases most rapidly and vigorously. The explanation is opposite to the graph for the boiling liquid. Thermal energy is transferred to cool liquid which leaves an impact of the exceeded kinetic energy on the particles. Particles start to vibrate and thus increase in temperature. 6 minutes is a short time for measurement of evaporation, because the temperature remains below the boiling point.

Conclusion:

In conclusion, the results have greatly supported the initial hypothesis about the relationship between temperature and rate of evaporation. The higher the temperature, the faster the evaporation rate therefore a drop in temperature. Temperature is recorded as most severely fall in the first 2 minutes, since that time high thermal molecules on the surface gain more kinetic energy and are able to escape and evaporate quickly from liquid surface. They vibrate vigorously. As learn from theory, temperature is proportional to the average kinetic energy f the particles, a lower kinetic energy means a lower temperature and this explains why he temperature of the liquid falls as evaporative cooling.

As for the opposite result obtained from cool liquid, it suggests that thermal energy input to place latent heat of vaporization to the cool liquid and its surrounding, therefore no evaporation took place, instead thermal energy increased to the boiling point. This explained for an increase of temperature in the cool liquid.

There is no anomaly found in this experiment. The patterns fit well with the theoretical background.

Error:

Small errors occur that we have not carefully planned for the experiment and therefore struggled at the beginning. This waste of time for struggling reduced the accuracy for the measurement of temperature, especially for boiling water, vapour could have been lost and the temperature would decrease. I also rounded up the thermometer reading if the degree was difficult to identify (in between two numbers or lines). Small mistake of time to stop the watch is also considered as an error though it is our reaction time and thus hard to make realistic improvement.

Limitation:

Time constraint is a major factor that prevented me from repeating the experiment more time. If I were to have more time, I would surely repeat this experiment to ensure a stronger set of data result evidence.

Realistic Improvement:

- It is important that one looks at as many and different aspects of the experiment as possible. Next time, I shall plan, design carefully for 1-2 hours and decided on which aspects would most likely to influence the variable

- To enhance the range of results, it is important that I should repeat the experiments many times and average the result.