Tagged: thermodynamics

Hot air rises - Physics Stop

Marcus Wilson Jul 14, 2011

Well, we have now moved into our new house. We moved last Friday, mostly dodging the heavy showers that have been marauding around the country for the last week. We are slowly unpacking - the place is looking a lot tidier now than it did at the weekend, but it will take a while to find a home for every … Read More

Chocolate problems - Physics Stop

Marcus Wilson Apr 26, 2011

Thinking back to last week's MasterChef (the chocolate tower of terror - re-live it here), there were a couple of nice examples of cooking being a branch of physics. I've heard it said that cookery is all about managing the flow of heat into (or, in this case, out of) an object, which, of course, requires some physics.The … Read More

Uses of Liquid Nitrogen - Physics Stop

Marcus Wilson Feb 17, 2011

I went to the doctor yesterday and he attacked me with liquid nitrogen.  To be more specific, I had a wart 'frozen' off.  Now, I had some similar treatment years ago, in which the doctor used a container of the stuff surrounded by polystyrene foam, and open to the air. Rather like what we use in the lab sometimes. He … Read More

Hot, heat, temperature and thermodynamics confusion - Physics Stop

Marcus Wilson Dec 16, 2010

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', etc confuse students when they come to learn thermodynamics? For … Read More

Negative Resistance - Physics Stop

Marcus Wilson Nov 16, 2010

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 the resistance is negative.It's not … Read More

Cold and humid - Physics Stop

Marcus Wilson Aug 10, 2010

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 makes you feel it is … Read More

Peak Oil, peak platinum, peak physics - Physics Stop

Marcus Wilson Jul 14, 2010

I guess most of us now are familiar with the concept of Peak Oil. At some point (maybe about now) oil production will peak, then it will be in decline as reserves run out. The only way around this issue is to reduce our use of it, which means, for example, reconsider our transport options.At cafe scientitique last week, … Read More

It never works when you need it to - Physics Stop

Marcus Wilson Jun 18, 2010

A couple of weeks ago my wife mistook an old glass jug of ours for a pyrex one and poured boiling water in it. The result was quite pretty, with a jigsaw of cracks across the jug rendering it incapable of holding any fluid ever again, boiling or otherwise.That's thermal expansion for you. Glass is a failry poor thermal conductor (in … Read More

Confusion and disorder - Labrinth

Vic Arcus Mar 01, 2010

Confusion and disorder go together in many respects. Politically…. Socially…. disorder and confusion are firm friends. But I would like to speak about disorder from a scientific point of view because in this respect as well, there tends to be confusion. And yet, disorder (or entropy) is one of the most important concepts in science. Peter Atkins (Oxford chemistry … Read More

Heads I win, tails you lose - Physics Stop

Marcus Wilson Jan 25, 2010

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 - http://sci.waikato.ac.nz/physicsstop ) How hot we feel has more to do than just what the temperature is.  Anyone who has stood … Read More