The hydrological cycle, described well in geography, is a physical phenomenon that is intriguing in how it can sustain itself without human effort. It depends on heat from the sun to vaporize water of the surface of the earth so that it rises and comes back down as rain. The same phenomenon is observed in everyday life in our living conditions. The purpose of the sun in the hydrological cycle is to provide heat. Humans, however, have substituted the sun with artificial heating. When any water body is heated to a certain temperature, it turns to vapor and is lost, unless it is cooled back down. This process is of great interest to virtually every family since the rate of loss of water stored in tanks and other reservoirs can be reduced if the concept of the factors affecting the rate is grasped. Although heating water in any container results in evaporation, the rate is dependent on the color of the container in which the water is kept. Some colors promote a higher rate of evaporation while others appear to reduce that rate. In the following essay, I am deliberating on the experiment conducted to find out the differences in the rates of evaporation from a cup when it is covered with different colored papers. The cup here is used to represent the water body while the different colored papers are used to represent the various colors used to paint water storage containers. This knowledge can also be applied to other liquids like petrol and kerosene.
To explore the topic further, some of the relevant ideas must be differentiated. First of all, there is a possible reduction in the rate of water loss from swimming pools if the color of the swimming pool floor is such that it reduces the rate of evaporation. Also, the rate of water loss from home storage tanks can be minimized if the color of the container or tank is one that does not encourage rapid water evaporation. Finally, a specific color of the cup can keep tea or coffee hot for a longer period without having to reheat it compared to other different colors that promote evaporation hence have a higher rate of cooling of the liquid.
The hypothesis for this project is the following: there is no difference in the rate of evaporation of water from cups covered with papers of dull colors and cups covered with papers of bright colors.
I shared the above idea of different rates of evaporation from cups covered with different colored papers with some of my classmates. Their responses were various. The first one was that it could be possible that there are differences, but they could be so small that they would be immeasurable. The second response was that although the experiment seems tricky to conduct, it is worth trying to see if my idea is supported by empirical data from the findings. The third response was that it is a good topic for scientific curiosity and that I should pursue the idea and prove its worth in daily life applications.
The requirements for this experiment are four plastic cups; all of the clear color, a white, black and a silver paper, a digital weighing balance, a watch, a masking tape, and an electric heater.
- Three of the cups will be covered with the three different colored papers and a masking tape used to fasten the papers. The fourth cup remains uncovered as the control;
- Water is heated to boiling using the electric heater;
- The cups are then filled with an equal amount of water (weighted in grams), and the initial weight is recorded;
- The cups, filled with water, are then put on the lab table and left to stand for 30 minutes after which their weight is measured and recorded in comparison with their initial weights.
The independent variable in this experiment is the color of the paper used to cover the individual cups. It also includes the uncovered cup.
The dependent variable, on the other hand, is the weight of each cup at the end of the experiment, which will be a reflection of the amount of water lost due to evaporation.
The control group is the cup that was left uncovered and is transparent (like glass) to gage the rate of evaporation in the case when the container does not have any specific color.
The fixed variables in this experiment are the ambient room temperature and the air flow within the lab setting.
The tools required for collecting the data are stopwatch and digital weighing balance. The stopwatch will be needed for timing exactly 30 minutes as the duration of the experiment. The digital weighing balance will be used to measure the initial weights of the cups after being filled with hot water and also the weight of the water at the end of the experiment. It will show the amount of water in grams, lost from each cup due to evaporation.
The possible outcome from the experiment is that the cup in a silver paper will show the least amount of evaporation, followed by the cup with white paper, then the uncovered cup, and finally the cup in black paper. The other possible outcome is that all the cups will show the same amount of water loss during the period of the experiment. The last outcome is that the cup with a black paper will show least evaporation, followed by the uncovered cup, then the cup in white and lastly the cup in a silver paper with the highest evaporation.
The results of the experiment
- Cup in silver paperweight at 0 minutes 50 g, weight at 30 minutes 49 g;
- Cup in white paperweight at 0 minutes 50 g, weight at 30 minutes 46.9 g;
- Cup in black paperweight at 0 minutes 50 g, weight at 30 minutes 44 g;
- Uncovered cup (control) – weight at 0 minutes 50 g, weight at 30 minutes 46.3 g.
Figure 1. Water evaporation graph.
My finding in this experiment was that the cup in black paper had lost the highest amount of water through evaporation (6 g) followed by the cup without a paper cover which had lost 3.7 g, then the cup with a white paper cover, which had lost 3.1 g and finally the cup with a silver paper cover which had lost the least amount of water (1 g). These results clearly indicate that the color of the paper that covers the cup has an effect on the amount of water lost through evaporation. The duller the paper used to cover the cup is (in this case a black paper), the higher the rate of evaporation and vice versa (for the silver paper covered cup).
My hypothesis was not supported by the data gotten from the experiment. It could be modified as follows: the rate of evaporation of water from identical containers is dependent on the color of the paper used to cover the individual cups.
From the above results, it is clear that the rate of evaporation is the lowest in bright colored containers and the highest in dull-colored containers. It can thus be concluded that the brighter the container’s color is, the more suitable it is for storing hot liquids for as long as opposed to dull containers which promote evaporation of the liquids .
Some of the strengths for this experiment are that the materials are easily available, and the procedure is relatively simple to carry out. Indeed, the costs incurred in the experiment were very low. On the other hand, some of the limitations of the experiment is that it is hard to do it on large masses of water, which makes it hard to estimate the real impact of effects of color on a larger scale. It is also hard to use the experiment to measure the amount of water lost from large masses which are dependent on the sun since it will take a very long time to heat the whole body mass and it is impossible to measure the changes in it.