Content area
Full text
Abstract
An experimental program was devised by the authors to provide students with practical `hands-on' experience of concepts of physics, and to increase awareness of the dangers of LTV radiation by a series of scientific measurements on LTV irradiance levels. A group of Year 10 students undertook the experiment and sample results are presented.
Introduction
The risk of developing non-melanoma skin cancer is related to the cumulative ultraviolet (UV) exposure and the risk of melanoma increases with the number of sunburns, specially during childhood. The highest incidence rates of non-melanoma skin cancer and cutaneous malignant melanoma in the world are in Australia (Parisi & Kimlin, 1997a). Queensland has low latitudes, relatively fine, warm weather and the population enjoys an outdoor lifestyle with resulting high skin cancer rates. The quantification of solar UV levels is an important part of increasing the awareness of the public to excessive UV exposure. Furthermore, the measurement of ultraviolet radiation may be used in the instruction of science students with regards to the concepts of measurement, the electromagnetic radiation spectrum, the energy of electromagnetic radiation, data analysis, molecular absorption and scattering.
Experimental
An experimental program was devised by the authors to provide students with practical `hands-on' experience of the above concepts, and to increase awareness of the dangers of UV radiation by a series of scientific measurements on UV irradiance levels. A group of seven students from Harristown High School, Toowoomba undertook the project with a series of measurements to determine the reflected, direct and diffuse solar UV radiation.
The UV waveband is comprised of the UVA (320 - 400 ntn), UVB (280 - 320 nm) and UVC (200 - 280 nm) wavelengths. No UVC is present at the earth's surface as a result of efficient absorption by oxygen and ozone in the atmosphere. The solar UV radiation at the earth's surface comprises a direct and a diffuse component (Parisi & Kimlin, 1997b). The direct component comes in a direct path from the sun, whereas diffuse radiation is scattered by the atmosphere, clouds and the surroundings. The molecular scattering increases with the fourth power of decreasing wavelength and as a result scattering is more significant at the shorter UV wavelengths compared to the longer visible wavelengths. Combined, the diffuse and...