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Teacher demonstrations help students understand heat and the methods of transfer - conduction, convection and radiation.
Invitation to Learn
Heat is made up of molecules
The Convection of Heat, by Eureka! (Films for the Humanities and Sciences, PO Box 2053, Princeton, NJ 08543, www.films.com)
Bill Nye the Science Guy: Heat (Disney Educational Products, (800) 295-5010, http://dep.disney.go.com/; ISBN 1-932644-98-9
Heat is the transfer of thermal energy between substances that are at different temperatures. Energy is always transferred from the warmer object (which has a higher temperature) to the cooler one (which has a lower temperature). Similarly, molecules with a lot of energy move faster than molecules with a smaller amount of energy, thus causing the former to have more heat. Heat transfer will continue until both objects have reached the same temperature or the same speed.
For example, an ice cube in a glass of water eventually melts. This is because the heat from the water, which is warmer, flows to the ice cube until both are at the same temperature, and therefore no ice cube is left.
There are three methods of heat transfer: conduction, convection, and radiation. Conduction occurs through direct contact. When two substances come into contact, their particles collide. The energy from the faster-moving substance is transferred to the slower-moving substance until they are moving at the same speed. At this point, their temperatures will be the same. An example of conduction is a spoon warming up when it is placed into a cup of hot cocoa.
Convection is the transfer of heat in air or a fluid through currents. An example is a pot of water warming up on a hot stove. As it heats up, the particles spread out and become less dense. The warm water on the bottom of the pot rises and displaces the cold water. As this occurs, the cold water sinks. So hot air rises, cools, and falls.
Radiation is the transfer of energy as electromagnetic waves. It does not need to directly touch anything or move particles as in conduction and convection. Radiation occurs through empty space, as in the sun heating the earth or feeling warm in front of a fire.
Many demonstrations are needed for this experiment. Prior to beginning the lesson, prepare several cups of beans and BBs. Lay cloth and a piece of glass on the snow or colored paper and glass on the pavement at least an hour before the lesson. Plug in the hot plate. Heat a cup of water to almost boiling. Set up the candle spinner or create the paper spinner. Make a transparency of Hogle Zoo Heat! Make sure the radiation portion of this lesson is done on a sunny day.
This lesson is divided into heat concepts and could be done over a two or three day period if desired.
2. Manifest science attitudes and interests
3. Understand science concepts and principles.
Invitation to Learn
Turn a hot plate to high temperature. Obtain the metal ball and ring set and instruct students to obtain their science journals. Show how the ball easily passes through the ring. Now place the ball on top of the hot plate. Allow it to warm, then try to place the ball through the ring again. It will not work. Ask the students to write the following in their journals: What happened when the ball was heated? Why do you think it won't it go through the ring now? What do you think will happen when both the ball and ring are heated? Set the ball and ring on the hot plate as the students write. When finished, again place the ball through the ring. This time, it will work. Were their predictions correct?
Heat is made up of molecules
Curriculum Extensions/Adaptations/ Integration
Loucks-Horsley, S., & Olson, S. (Eds.). Inquiry and the National Science Education Standards: A Guide for Teaching and Learning. Washington, D.C: National Academies Press, 2000.
Word Smith as you Choose discusses engaging students in exploring and communicating their thinking through writing, which has shown tremendous benefits in science and mathematics. Writing explorations help students in understanding concepts more deeply, improving problem solving strategies, assessing their personal thinking skills, learning to consider themselves as deep thinkers, and overall becoming better learners in and out of the classroom. Journals are concrete and visible evidence of student thinking, effort, and progress. They should show if students have or have not achieved the desired learning, if they have misconceptions, their reflections, their journey towards understanding a concept, and/or if more instruction is needed.
Kruger, A., & Sutton, J. (Eds.). (2001). EdThoughts: What we know about science teaching and learning. Colorado: Mid-continent Research for Education and Learning.
This book supports standards-based reform of science education. Research and best practices are provided, as well as ways to improve classroom instruction. A list of additional resources is also available for those desiring deeper understanding of certain concepts. All articles rely on the national standards for best practices. A common theme is the importance of quality science education for all students.