Atmospheric Processes - Radiation Raheel Aslam Prasad Weerakoon

Testing Procedures, Problems and objectives 300W Bulb Lamp Which material absorbs more heat in the first ten minutes ? Procedures: We filled the pans to the same level with different materials. Placed those pans under the lamp about 12 inches. Placed thermocouples just under the surfaces of each material. Turned the lamp on and measured the temperatures for ten minutes. Using the data tables, we plotted the graph of the heating cycle to compare the rates. Even though there was not enough intensity of light, we still got pretty good results as expected. Dark Wet Soil Light Sand Water Stop Watch Thermocouple

Data tabels and Graphs Surfaces Heating Cycle 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 Water (°C) 21.0 21.3 21.6 22.0 22.5 23.0 23.5 23.9 24.2 24.5 25.0 Dark wet soil (°C) 12.7 14.2 15.6 16.8 17.9 19.0 20.1 22.4 23.6 25.2 Light sand (°C) 14.1 14.9 16.0 17.2 18.4 19.6 20.6 23.4 24.1

Discussion and Results From the graph, it was clear that dark-colored objects absorb more visible radiation. It was wet dark soil with some grass and plant roots, which might have caused results to deviate. Basically, results showed gradual increase in the temperature of three material surfaces. To get better results, use a reflector lamp which provides high intensity of light.

Conclusions and Recommendations From the results we can conclude that the amount of energy absorbed by an object depends on the following: 1. The object's absorptivity, which, in the visible range of wavelengths, is a function of its color. 2. The intensity of the radiation striking the object As mentioned in the previous slide, the soil that was used had impurities in it and that may have changed our reading somewhat. However, that can be ignored as the percentage of impurities is not significant enough to change the abosrptivity of the soil sample.