ConvectionGCSE PHYSIC

By Aadeng Apang

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What is convection ?

• Convection is the process in which heat is transferred in a substance by the actual movement of the heated particles.

• Convection takes place only in liquids and gas.

• The transfer of heat in convection is always vertically upwards.

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Why is the transfer of heat by convection vertically upward ?

This is because the particles of the medium near the heat source gets heated and starts to move faster. Then, the heated medium expands and becomes less dense therefor it rises and take place of the medium above which is more denser. The denser medium then takes place of the less denser medium.

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Convection Currents

When liquid is heated the less dense warm liquid rises above the more dense cold liquid due to the particle vibrating and moving faster. This causes a circulation and convection current is formed in the process. The convection current continues till the entire medium has the same density and temperature.

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Convection in Gases LAND BREEZE

During day time the air surrounding us gets heated by the sun and becomes warm and dense resulting it to rise up. The cool air from the sea replaces it

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Convection in gases

SEA BREEZE

At night the land cools down faster than the sea therefore the warm air from the sea rises up and is replaced by the cool air from the land.

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Works Cited• "Convection." BBC News. BBC, n.d. Web. 09

_2011/energy/heatrev1.shtmlNov.2014.http://www.bbc.co.uk/schools/gcsebitesize/science/aqa_pre http://www.bbc.co.uk/schools/gcsebitesize/science/aqa_pre_2011/energy/heatrev1.shtml

• "Heat Transfer." Heat Transfer. N.p., n.d. Web. 08 Nov. 2014http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/heatra.html http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/heatra.html

• http://www.gcsescience.com/pen7-convection-density.htm

• "Learnhive | ICSE Grade 9 Physics Transfer of Heat - Lessons, Exercises, and Practice Tests." Learnhive | ICSE Grade 9 Physics Transfer of Heat - Lessons, Exercises, and Practice Tests. N.p., n.d. Web. 09 Nov. 2014.http://www.learnhive.net/learn/icse-grade-9/physics/transfer-of-heat

• DAsh, S.K. "Google Books." Google Books Physics. N.p., n.d. Web. 07 Nov. 2014.( Icse Physics)

• "Convection." Definition of Convection. N.p., n.d. Web. 09 Nov. 2014. http://www.icoachmath.com/physics/definition-of-convection.html

• http://ap-physics.david-s.org/convection/