## Hot, heat, temperature and thermodynamics confusion

Consider the following perfectly reasonable sentences: "It’s hot outside" "The oven is heating up" "Insulation helps keep a house warm" Here we have physics words and concepts being used in everyday English in ways that are rather loose from a physics point of view. Does the conventional English use of words such as ‘heat’, ‘temperature’, ‘insulate’, […]

## Negative Resistance

I was having a conversation last week with a student about negative resistances (in an electronics context). These are just as they sound – to send a current from terminal A to terminal B you have to apply a higher potential to terminal B than terminal A.  Sounds backwards?  Yes – it is. That’s why […]

## Aircraft insulation

I read in the NZ Herald this week that one of Air New Zealand’s energy-saving strategies was to make sure an aircraft’s insulation is dry. Apparantly, 200 kg of water can be sucked out of a plane’s insulation.  Sounds impressive. The article appeared to be pushing the weight saving as the main cost saving. Two hundred […]

## Sticky Milk Powder

Earlier this week, we had the end-of-year display of student engineering projects. There were lots of posters put up to browse around over tea, several interesting large objects such as pieces of electric cars, and many fascinating talks given by the students. One of the most enjoyable talks was given by student Timothy Walmsley, concerning a study on […]

## Cold and humid

Saturday was one of those days that the Waikato winter is famous for. Cold and damp – by damp I mean humid as well as raining – in fact the kind of weather that reminds you that you are living in an area that used to be one massive swamp. The sort of dampness that […]

## 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 […]

## 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 […]

## 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 […]