Posts Tagged ‘Convection’

This is my second mind map in an attempt to visually display the draft Science Curriculum in England and this time the focus of the Mind Map is Energy. In my previous post on this issue I set out to see how coherently the new curriculum has been written and I suggested that depending on how difficult it would be to mind map the various parts of the curriculum could give an indication of that. I have to say that in this second Mind Map I could find quite a few key ideas that interrelated to other branches quite nicely. However, I felt that I had to separate Conservation of Energy from Dissipation of Energy, even though the new curriculum has them under the same heading (which is fine in the document I think), as I wanted to stress the importance of the Principle of Conservation of Energy. Something I was not too sure about was the inclusion of renewable energy sources and fuel resources under the Conservation and Dissipation section. As a whole I am fairly pleased with this Mind Map and I think the development of this unit is quite coherent. I might have missed something though and I value your comments in that respect.

You can use the Mind Map below, or download the iMindMap version and edit it from this Biggerplate page.

Physics Energy

I first saw the demonstration in the video below done by Clare Thomson at the “Best of PhysEd” lecture at the ASE Conference in 2010. Ever since I tried to make various versions of it, from using two very tall gas columns, filming it with high frame rate cameras, etc. But today I think I have made a really interesting variation of this really nice demo. The video below was made this morning in my kitchen.

Recreating this demo is very simple and I strongly recommend you do it with your classes, because the colours in the video don’t really reflect what you can see with your naked eye. I used water beads that I previously immersed in water containing blue food colouring for the cold water beads and red food colouring for the hot water beads. You will need to leave them in dyed water for about 8 hours. Then, I put cold water in the glass with blue beads and boiling water in the glass with red beads. When you mix cold and hot water with the cold water at the top, the red bead (much hotter) will rush upwards and the blue beads (much colder) will fall downwards. As the two types of beads swap places you have a nice simulation of what happens to the particles from hot and cold water, i.e. with more or less kinetic energy, when they mix. You have a very visual representation of a convection current forming in the two glasses. There is a limitation though, in fact, you can see that after a while the red beads begin to fall and collect at the bottom on top of the blue beads, but this is still quite effective at making the point that they have swapped places.

Hi, have I told you I work for NGfL Cymru? Probably a thousand times 😉

In the video below I show a great animation on convection currents in a room heated by a radiator that you can find on our website here. However, I don’t just give a tour of the animation, but I show how you can use it to encourage your students to talk about Physics in a creative way. It is a role play where you introduce the animation as a talk show of the life of the “Particles” family, which is your class. Well, the rest is in the video and I don’t want to spoil it for you, but I believe this approach is an interesting way to develop Communication and Literacy skills in your pupils in a fun way!

As always, I really value your feedback, so spend 10 seconds to leave a comment, please!

At last I have found some time to check Prezi out, and it’s even better when you can use this time to fit it in with your job. As a Field Officer at NGfL Cymru, I am trying to develop resources that give opportunities to learners and educators to explore the latest technology and its applications in sound Learning and Teaching. So, I could not leave Prezi out, especially after all the feedback I had received before I started using it myself! However, I wanted to find a use that was not just different from another way of presenting (which in my opinion is not the point and certainly not what would make Prezi stand above PowerPoint, because we’ll soon have death by Prezi if we are not careful),  but that would have real educational value and that would be an advantage to anyone using Prezi in this way!

To cut a long story short, I was wondering what it would be like to mind map with Prezi, and by mind mapping I mean following the mind mapping rules set up by Tony Buzan (the creator of Mind Mapping himself). One of the greatest advantages of Prezi in drawing mind maps is the ability to embed videos in your Prezi mind maps, something we haven’t seen before (at least I haven’t in other mind mapping software). Also, assigning a path to your mind map allows you to show and share your thought process very clearly. In this way using a Prezi mind maps could become a very effective presentation tool, but also a revision tool for your students who will need less assistance from the author of the mind map, because the sequence of events and areas of focus is decided by the path set by the author themselves! However, if a learner prefers to go at their own pace and stroll around your mind map their way, they can still do this by zooming in and out with the scroll on your mouse. You can also set the Prezi to be public and with the option to be copied by people who bump into them! So, your students could copy your Prezi mind map in their Prezi accounts and edit it to make it more suitable to their learning style, or simply add to it. Why not starting a template Prezi mind map and let the learners complete it? Then, you could share the contributions from different pupils in the class and complete your draft as a collaborative mind map created with each learner’s contributions, which is a very useful and highly effective mind mapping technique!

Click here, or on the image below to see my first Prezi Mind Map on the Kinetic Theory.

Here is a lovely classroom demonstration that I saw at the ASE Conference 2010 in Nottingham. The demo was part of the Physics Education Lecture, which displayed the best of the PhysEd magazine. I really learned a lot and was well impressed by the quality and creativity of the demonstrations, activities and workshops proposed by the Institute of Physics. As one of the IoP Network Coordinators I was very proud to be part of the Institute and see how many outstanding workshops and lectures they put together for the event. Apparently, the IoP did the majority of workshops and they were all free of charge, although the conference was organised by the ASE.

Anyway, coming back to our demonstration. At the lecture it was shown using two small glasses, so when I went back to my lab I thought; “What would happen, if I use two very tall columns of water? And this was the result!

Why don't the two liquids mix?

So, why won’t the two liquids mix?

I put cold water in the bottom column with some blue food colouring and boiling hot water in the top column with some red food colouring. The tricky bit is how to turn the top column upside down, as it is really hot and heavy, but it was well worth it! So, I put a sheet of paper on the top and then carefully turned it upside down (you might need a helper to do this). Then, I placed the top column on bottom one and as you can see, and unlike what the kids would expect, the red and blue water don’t mix. They actually stay unmixed for a very long time (over an hour at least).

But how do we explain such an effective phenomenon? Well, the hot water is less dense than the cold water at the bottom, as its particles have more kinetic energy, hence moving further apart from each other. The result is that we have two liquids of different density, with the less dense one at the top, which therefore will float on top of the denser cold water. It is a bit like having oil and water, you can tell your students!

This is a really nice demonstration that will really help your pupils to understand that hot liquid rises and cold liquid falls. It’s not only very memorable, but it also shows quite clearly that in heat convection currents it’s not the “heat” that rises, but the hot liquid, or gas.