Random odds and ends

No major theme or single lesson this week, just a few  random ideas that I’ve used in lessons this week, either as introductions or illustrations, part of the essential punctuation of any lesson plan to prompt thinking, help clarify or just provide some variation.

Year 13 and Hox Genes…

This follows their investigation into the Lac Operon (which worked beautifully this year – just fabulous results – see 25th Sptember 2014). With no introduction, I start the lesson with this Mitchell and Webb sketch.  After the initial shock and hilarity, ask the question – what is the serious underlying point here? Why don’t people grow buttocks on their heads? (or 19 penises for that matter, if you decide to show the next clip in the sequence). The genes for buttock formation are all there in the cells of your head. Why is it a head at all, and not, say, an arm? Sounds silly? Show some pictures of fruit flies growing legs out of their faces and eyes at the end of their legs. Hox genes for blog I’ve also included a little animation to illustrate the point that these genes are exactly the same in all animals. So a hox gene taken from a fruit fly will perform exactly the same job in a mouse. Or a shark. Or a chicken. Or you…

Year 12 and Potato Osmosis….

…and trying to push them beyond the simple explanation of mass gain vs mass loss as a result of water potential gradients (which they should have been able to do in Year 9). I want them to explain the whole shape of the graph. They look confused. What does this mean? It can take them a while to see what I’m getting at as I push for a more rigorous description, but the question is, why does it lose more and more mass as the sugar concentration increases? And why does it start to level out at the highest sugar concentrations?

Going from the abstraction of the graph to the specifics of potato tissue is not easy, and one class was clearly struggling, so I turned to a trusty balloon to help them visualise it and make the link.

Sketch the graph on the board. Inflate a balloon. Balloon = potato cell. Air = water. All clear?


Move it along the line – sugar concentration has gone up – water potential difference is greater – what happens? Let a little air out of the balloon.


Move it further along. What happens? Let a little more air out.


By the time you get to the plateau, there’s no air left to come out – the mass of the balloon/cells won’t change much.


They liked this. Hope you do too.


3 thoughts on “Random odds and ends

  1. Nicola Addy

    Dear Paul, I’ve been following your blog since September and want to thank you for sharing your thoughts, ideas and resources. I have stolen/borrowed numerous lesson ideas and have been inspired to create many more with the same aim. My Year 10s were scared to death at the prospect of designing a vaccine and planning a clinical trial with no input from me (other than a badly drawn made-up virus structure and some information sheets about the pros an cons of different vaccine types). I have spent years spoon feeding them information and watched them panic and nearly give up before the light bulbs started going on in their different groups as they talked through the task with each other. What a revelation! They argued ferociously about the merits of using different antigens in their subunit vaccines and I thoroughly enjoyed my gingerbread latte as they did so. They haven’t done DNA structure yet, but they figured it out for themselves and how mutation could change the tertiary structure of the antigens. Wow. I really can’t thank you enough for giving me the confidence to let go and allow the students to take ownership of their learning. It makes lessons so much more fun! (But I’m still having secret panics that they don’t know anything – hopefully this will pass!!) I’m just sitting down to plan an intro to the immune system for my year 12s and wondering how to incorporate some of the ideas I used with year 10. Or maybe some lego… They loved that when we did protein structure (though our bursur wasn’t best pleased!) I can see how I usually bore them to death with how amazing the different immune responses are and how intricately detailed. Who knew? I would love to hear how you have approached it. Many many thanks again, Nicola Addy

    P.S. I have also discovered that strawberry bootlaces make excellent spinal cords! My year 9s had great fun drawing around each other and sticking on the CNS and basic peripheral nerves (different coloured wool). The shock on their faces when I snapped a bootlace to demonstrate how delicate the spinal cord is was priceless. And they will certainly never forget!

    Sent from my iPhone


    Liked by 1 person

    1. paulweeks2014 Post author

      Dear Nicola, Thank you so much for this! I must admit I’ve been wondering whether to continue writing the blog, so to have such a wonderfully positive response has not only made my day, but made me want to carry on writing. Thank you again. Paul


    2. paulweeks2014 Post author

      And as a PS – I find that when I set a test, students report that when they came to revise for it, they found they already knew it! Because, of course, if you understand something, you therefore know it. Don’t panic! Plus students who are excited and interested in a subject will WANT to do well and will work hard and therefore do well… and you quickly create a virtuous circle. Plus it doesn’t seem like work, if you enjoy it. Love the idea of a strawberry bootlace spinal cord. I’ll put something on the Immune System in today’s blog…



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