# MathsClass

A blog about teaching and learning in a maths classroom.

## Heat Sinks - Surface Area

Monday, 16 November 2009 | 3 Comments

I’m about to get into Surface Area with Year 8.  Of course, there will be chocolate.  But, since I last looked at Surface Area with Year 9 I’ve been thinking about Heat Sinks.

A heat sink is used in electronics to dissipate heat from electronic components.

The most common design of a heat sink is a metal device with many cooling fins. The high thermal conductivity of the metal combined with its large surface area due to the fins results in the rapid transfer of thermal energy to the surrounding, cooler material. This cools the heat sink and whatever it is in direct thermal contact with. Wikipedia

I’m sure there’s a lesson here, just not sure what it is… ideas?

A bit of a wcydwt, if you like.

At the minimum, I think there’s at least the engagement factor of understanding the importance of surface area in keeping your computer cool.

Posted in • Lesson IdeaSurface AreaMediaPhotoWhat can you do with this? | Short URL: http://mths.co/1619

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Cathy on  17 November 09  at  12:40 AM #
Why are bacteria small? Why do your intestines have microvilli? Why use castor sugar in cooking? Is it better to have one closed nutella sandwich or two open faced nutella sandwiches?
Mr. H on  17 November 09  at  02:32 AM #
Try a little origami. Show them a heat sink and 3 sheets of paper; one that roughly corresponds to the surface area, one larger, and one smaller. Label each sheet with the dimensions. Ask students to make some guesses. Build intuition or maybe surprise them. Ask students to make calculations. Show them a prefolded solution. Check their intuition. Maybe give each student a sheet of paper and try to come up with heat sinks with more surface area? This is not science class, but you can get some [url="http://www.roymech.co.uk/Related/Thermo.html"]thermo numbers here[/url] and ask students about what surface area is needed if you created heat sinks using different materials (e.g. gold, copper, silver, plastic, cotton wool) A similar problem is [url="http://numberwarrior.wordpress.com/2009/10/09/what-can-you-do-with-this-giant-ants-of-doom/"]giant ants of doom[/url] at the Number Warrior. It's about surface area and oxygen absorption.
Tim on  18 November 09  at  09:58 PM #
Surface area of car radiators. Cooling fins on the cylinders of aircraft engines (& motorbike engines). Evaporation from swimming pools. Putting a spoon in a hot drink to make it cool quicker.

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Simon Job — eleventh year of teaching maths in a public high school in Western Sydney, Australia.
MathsClass is about teaching and learning in a maths classroom. more→

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