CONVECTION
and VENTILATION BOX
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Author(s): Jim Schwagle and Nabila jahchan |
Demonstration Equipment - Teacher's Guide |
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Principles illustrated: 1) warm air rises 2) warm air is less dense than cool air 3) convection procedure and flow of air Convection can be defined as the transmission of heat by the movement of heated gases. The heated gases from a burning substance move, forming a current. |
Plac |
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Standards addressed: High School Earth Science 5a 5. Heating of Earth's surface and atmosphere by the sun drives convection within the atmosphere and oceans, producing winds and ocean currents. As a basis for understanding this concept:
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Materials |
Explanation of principles involved |
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Rectangular box with a clear transparent plastic side 2 plastic tubes acting like chimneys 1 candle 1 touch paper 1 box of matches |
. "Hot air rises, and cool air falls to take
its place." - This is a description of convection in our atmosphere. The
circulation of the air transfers heat energy. Simplified, convection is any flow that 1.
picks up heat at
one place, 2.
transfers the heat
to another place, 3.
and is driven by
this transport of heat |
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DIAGRAM:
DESCRIPTION: The convection apparatus consists of a wooden box with clear plastic sides and two chimneys. A lighted candle is placed beneath one of the chimneys and a burning taper held over the other. The convection current is clearly visible. |
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Procedure: 1.
Very CAREFULLY,
using a fireplace match, light the candle by putting it down the chimney.
Once the candle is lit, allow the box to warm up for approximately 5 minutes. 2.
Roll a touch paper
into a tight, coiled tube. 3.
Light one end of the touch paper, allow it
to burn for about 10 seconds 4.
Extinguish it by blowing it out or shaking
it rapidly. (Be careful!) It should be smoking profusely. Note that the smoke
rises. 5.
Now, hold the smoldering paper down over
the second chimney (without the candle). 6.
Record your
observations.
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When you hold the smoldering paper down over the chimney without the candle, the smoke goes down with the cold air |
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Description |
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Description |
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References & Links: http://www.ph.unimelb.edu.au/staffresources/lecdem/hc4.htm http://nasaexplores.com/show_912_student_st.php?id=02122495101 Students can prepare their own ventilation box by following the steps shown in the following link: http://nasaexplores.com/show_912_student_st.php?id=02122495101 |
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