Infra-red and heat

Here’s a bit of physics that’s coming up in my lectures – what’s the connection between heat and infra-red?  You’ve probably seen imagery from ‘thermal imagers’ or infra-red (IR) cameras, usually on police shows, taken from a helicopter as it follows a suspect fleeing down some alley-way at night.  You’ll see that ‘hot’ things (like […]

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It’s cold outside…

…Well, it was this morning. Those unfortunate people like us who have two cars and a lot of stuff and only a double garage, meaning one car has to sit uncovered on the drive, will have noticed that the ice on the car windscreen is generally thicker than the ice on the side windows. Why is […]

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Why you need to proof read

I’ve just supervised a test for a group of second year students. On looking at their answers afterwards, it was rapidly clear that there was a problem with one of the questions. Specifically, I had given the value of Boltzmann’s constant as 1.38 times 10 to the power 23  Joules per Kelvin, instead of 1.38 […]

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What goes up… must come down

Yesterday morning while driving into work I was reminded that this week is ‘Balloons over Waikato‘ – the annual hot air balloon festival.  It was hard to miss; I counted 20 balloons making their way gracefully over south-east Hamilton and drifting slowly towards Morrinsville. (NB: I counted the balloons AFTER I had parked the car, […]

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Mobile phone physics

Just occasionally, I have a crazy thought regarding a physics demonstration.   This is one that I’m thinking about inflicting on my third year electromagnetism class.   We’ve been discussing the way electromagnetic waves travel (or rather, do not travel) through electrical conductors. Basically, conductors allow electric currents to flow in response to an applied electric field (in simple terms […]

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Fallstreak cloud

Those of you who check out the NZ metservice website frequently, may remember last week’s ‘photo-of-the-week’: It’s of fallstreak cloud, and this example was spotted by my mother-in-law, Barbara Seccombe, off the coast from New Plymouth recently.  (Photo credit to my father-in-law, Wally Seccombe, used with permission). It’s not something you see everyday, so I asked my brother […]

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Heads I win, tails you lose

The comment on my previous entry raises a few  issues with the way we feel heat.  (NB for those who normally read this blog on http://www.sciblogs.co.nz , you’ll need to go onto physicsstop to see the comment – https://sci.waikato.ac.nz/physicsstop )  How hot we feel has more to do than just what the temperature is.  Anyone who […]

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Can you feel the cold?

Writing the last piece about fridges has reminded me about a comment I heard from a fellow student while I was an undergraduate. I can’t remember the exact circumstances, but it quite possibly had something to do with objects in liquid nitrogen.  Anyway, the comment was something along the lines of ‘The temperature’s so low you […]

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