FRAMING PATHWAYS TO ANSWERS: THE SCIENTIFIC PROCESS IN ACTION
My Angle on Cooling
Effect of Distance and Inclination
Grade Level: 5-8
Duration: One to Two - 45 minute periods
In this lesson, students discover that one way to cool an object in the presence of a heat source is to increase the distance from it or change the angle at which it is faced. The students perform an experiment that measures how the heat experienced by a test subject changes as the distance or the viewing angle changes. The students learn to distinguish which effect is more important for determining the seasons on Earth. They learn how the MESSENGER mission to Mercury takes advantage of these passive cooling methods to keep the spacecraft comfortable in a high-temperature environment.
How do distance and inclination affect the amount of heat received from a heat source?
Sunlight can be felt as heat when it interacts with matter .
The intensity of ight decreases as the distance from the light source increases.
The angle at which a light source is viewed affects the intensity of light to which the object is exposed and therefore the amount of heat generated in the object.
Seasons on Earth are caused by the 23.5° tilt of the Earth's rotational axis, and by the resulting changes in the angle of sunlight arriving in different parts of the world at different times of the year.
MESSENGER Mission Connection
Because Mercury is much closer to the Sun than the Earth, a spacecraft studying the planet is exposed to more sunlight than objects on Earth. Two cooling methods used by the MESSENGER mission are making sure the solar panels do not view the Sun face-on, and keeping the distance from the sunlit areas of Mercuryís surface large enough to limit the amount of radiation received from the surface.
Standards & Benchmarks
NATIONAL SCIENCE EDUCATION STANDARDS
Standard D3: Earth in the solar system
- The sun is the major source of energy for phenomena on the earthís surface, such as growth of plants, winds, ocean currents, and the water cycle. Seasons result from variations in the amount of the sunís energy hitting the surface due to the tilt of the earthís rotation on its axis and the length of the day.
Standard B3: Transfer of energy
- The sun is a major source of energy for changes on the earthís surface. The sun loses energy by emitting light. A tiny fraction of that light reaches the earth, transferring energy from the sun to the earth. The sunís energy arrives as light with a range of wavelengths, consisting of visible light, infrared, and ultraviolet radiation.
Standard G2: Nature of science
- Scientists formulate and test their explanations of nature using observation, experiments, and theoretical and mathematical models. Although all scientific ideas are tentative and subject to change and improvement in principle, for most major ideas in science, there is much experimental and observational confirmation. Those ideas are not likely to change greatly in the future. Scientists do and have changed their ideas about nature when they encounter new experimental evidence that does not match their existing explanations.
BENCHMARKS FOR SCIENTIFIC LITERACY (AAAS PROJECT 2061)
- Read analog and digital meters on instruments used to make direct measurements of length, volume, weight, elapsed time, rates, and temperature, and choose appropriate units for reporting various magnitudes.