Category Archives: Key Stage 3

Gel electrophoresis

Not much to say this week, just some pretty pictures. It’s a kit supplied by Carolina Biological and our wonderful technician of the year suggested that it would be a suitable activity to include in the new Year 7 Separation topic. It’s an introduction to the concepts of Gel Electrophoresis and it works….

…. well, see what you think! Here’s the set up, with a bit of white card below the tank to help see what’s going on…


The gel runs in about 15 minutes with a decently powered pack so it fits into a double lesson…


The protocol separates various dyes and includes 3 unknowns for the students to analyse.


They absolutely loved it.

Lesson Planner’s Block

Welcome back to Biological Burblings, and welcome to a new academic year. I hope you all had wonderful summers.

It’s been the usual hectic start to the autumn term. Not one, but TWO (joy) days of INSET, or professional development, or whatever you want to call it (I could think of a few choice words….). Then a day of students in school but no teaching. And then, on the Friday, I took 27 Year 13 students to darkest Somerset for the Biology Field Trip and a full set of ecological Practical Skills Assessments. More joy.

Actually, the field trip is a genuine joy. Nettlecombe Court ( is a glorious setting, an old red sandstone stately home surrounded by deep valleys and ancient woodland and some of the biggest trees I’ve ever seen anywhere. The students are invariably brilliant, we always seem to catch the best of the early September sunshine, there are endless cups of tea and cake, and it’s a gentle way of easing back into the term after the summer holiday. With the abolition of PSAs (I have a bottle of champagne set aside for when I mark the very last one of these wretched distortions of scientific inquiry), there is no longer a compelling reason to organise a field trip, but I’m pretty confident we’ll retain it. It’s popular, successful and enjoyable and – with the OCR Biology A course – there needs to be some ecological investigation in the practical portfolio. I rather like the idea of letting students ask their own questions and design their own investigations. What are other people thinking?

We returned late on Monday, so actual teaching didn’t start for me until Tuesday. Four days of lessons later and I already feel exhausted….

….but we’re up and running. This year I have three Year 13 classes, two Year 12 classes, a Year 7 and a Year 8, as I continue my self-appointed task to re-write the KS3 Scheme of Work. So I’ve got no iGCSE teaching at all. The Year 12s are underway with the new A-level, but still starting with Water – see my blog from 22nd October last year for ideas on this. A colleague of mine also had the wonderful idea of freezing equal volumes of water and olive oil in separate plastic cups. The comparison of volume after freezing is dramatic and, better still, the frozen olive oil cube sinks like a stone in liquid olive oil.

I teach both sides of the Year 13 course, so two groups have tackled Squiggle Chemistry, where they figure out Chemiosmosis for themselves using the same evidence that Peter Mitchell used (Squiggle Chemistry) whilst the other one has launched into maggot innate behaviour experiments and the chance to try out their new found statistical knowledge. For any of you who don’t like teaching statistics, try introducing the Chi2 test with the opening from Rosencrantz and Guildenstern Are Dead, by Tom Stoppard. If you don’t know the play, here’s one version of the first scene ( And here’s the script
The play starts with the two characters gambling by flipping a coin – which has come down Heads 85 times in a row. The winning character, Rosencrantz, who gets a gold coin every time it comes down Heads, is a bit embarrassed but clearly not too bothered. Guildenstern, however, is deeply disturbed, not because he’s lost a shed-load of money, but because there’s something funny with the fabric of the universe. A coin cannot come down Heads 85 times in a row….I ask the students at what point they would stop playing. And introduce the idea that statistics is basically just a way of finding out if you’re being cheated – or if something funny is going on. It’s also a nice way of thinking about alternative explanations – if something doesn’t match your Expected, how could you explain it? Loaded coin? Double headed coin? He’s lying?

As for the KS3 classes, I’m reviewing and revising the Year 7 lessons that I wrote last year, whilst writing an entirely new SoW for the Year 8s. I love the excitement and creativity of generating new lesson plans, but because the Science lessons are standardised across the two year groups, it also means I’m planning new lessons for 3 other teachers who, understandably, want to know they’re getting something good and reliable. That’s quite stressful. I can go into my own lesson completely unprepared and improvise, busk, entertain, distract. But I can’t expect other people to do the same.

And on Thursday night it almost came unstuck. I was shattered, absolutely cream crackered, barely able to keep my eyes open, only just awake. And I had to have a new lesson ready for the next day. I knew what I wanted to do – something on the Nervous System to link to the work they had already done on muscles and bones. But my mind was blank. I scribbled down some random thoughts on how to introduce the topic. But what then? I wanted some kind of experimental investigation that would be fun and different and memorable. The old course was extraordinarily content heavy – masses and masses of facts to be delivered and regurgitated on demand. I want to pull it to the other end of the spectrum – no notes, not much talk, lots of Learning By Doing. But it wasn’t happening for me. My mind was completely blank. Sure, there’s lots of stuff out there, but I was reluctant to steal stuff from the iGCSE course, even if part of me was saying, “oh, just do the ruler reaction time practical, or the skin sensitivity practical.”

But I had no inspiration. So I got up and walked around and did the washing up and turned the children’s lights out and got my stuff ready for the next day….

And then went back to my desk and wrote a lesson plan based around the Sheep Dash game Which would be quicker, to dart the sheep by watching them? Or darting the sheep when they hear a friend say “baaa” when they see a sheep run across. There’s data to collect, means to calculate, graphs to draw, comparisons to make and explanations to explain. It’s not the greatest lesson in the world, but they’ll talk about it when they go home and I’ve bought an extra week to think of the next two lessons….

The hamsters are amazed

My Year 7s return from a week long residential in deepest Somerset to start the final topic in their completely re-written Year 7 KS3 Scheme of Work. I’m quite excited about this, but also slightly nervous. As always with a new idea, there’s the lurking anxiety, will it work?

It’s Biology’s turn and I’ve decided to chuck out the flowering plants. They get to do this in Year 9 as part of their iGCSE and, frankly, you can have too much of a good thing. Plus, while there are fun things to do with pollen grains/tubes and dead nettle dissection and trying to address the whole bizarre concept that flowers are SEX ORGANS and that, yes, plants HAVE SEX, and hay fever is caused by… but let’s not go there…. it’s not really a topic that lends itself to investigative experimental question asking. It’s much more from the “here-are-lots-of-strange-words-and-weird-structures-and-you-need-to-learn-them-for-the-exam” school of information delivery, a throw-back to the days when all science really was just Physics or stamp collecting. Biology has moved on from just describing stuff; so should we.

So I’ve turned to an area very close to my heart, one I did my PhD in, and one that has been brutally stripped from the new A-levels – Animal Behaviour. After all, it they’re not going to study it anywhere else, they can do it in Year 7. Plus, cunning laugh, it allows me to put my baboon behaviour resource firmly into the Year 7 curriculum. More on that in a future burble. Today was just the introduction, and it’s back to the hamsters.

Quick review with accompanying pictures:Introduction to hamsters with notes

What’s this?       A hamster!

Where does it live? In the desert! The Syrian desert!

What’s it like in the desert, the Syrian desert? Hot, cold, dry, exposed, sparse food.

How on earth does a hamster survive in such an extreme place?

They’re very good at this. Lots of good ideas on camouflage and burrowing and cheek pouches and being nocturnal, having good sense of smell and so on. Excellent. They are children of Attenborough. Let’s focus on the behavioural adaptations.

I get them to sit in a closed circle, on their knees, no gaps. I then plonk the docile furry bean bag that is Herbie the hamster into the circle. I tell them to watch what he does. How is this behaviour helpful for surviving in the desert?

It works really well. They love seeing Herbie, they all get a chance to stroke him as he goes round, and they’re perceptive. Herbie is exploring, Herbie is sniffling, Herbie likes tunnelling into gaps. This all makes sense. What else? It’s so obvious that it takes them a while to see it, but eventually they do – Herbie sticks to the edges – he never ventures out into the middle. Again, they instantly see why this makes sense for a small, edible organism foraging in an exposed environment.

So that’s the introduction. We’re going to be investigating animal behaviour and why animals do what they do – how does it help them survive?

I then introduce the idea of mazes. Can they think why it’s easier to investigate behaviour in a laboratory setting? Brief discussion on this, as I want them to get started on their project. Right, here are the kind of questions you can ask with mazes.

In groups of 4, I tell them to decide on a question – one of the ones I’ve suggested, or one of their own, and then build a maze to test it. They are VERY happy with this! Year 7s, cardboard, scissors, sellotape, the chance to make something and then put a hamster into it…. I haven’t seen them this happy since they made apple juice in the autumn term.  They’re off and running.

Of course, being Year 7s, the excitement of maze building might distract them from the scientific question I want them to ask. Sure enough, a couple of the groups haven’t quite thought it through. There’s some nice ideas about hamsters and smell, and hamsters in the dark vs hamsters in the light, but they’ve not narrowed it down to a simple, testable hypothesis. It’s the price you pay for being open ended. I like the excitement and motivation that ownership of the project gives the girls, and they can generate some superbly original ideas, but they will need quite a lot of support along the way. It’s important to keep circulating, to keep talking, to keep asking them questions.

We talk about some of the options. How could they improve this? What are they going to measure? They start to become more focussed. The other groups are fine – they really seem to have grasped the idea of simple, controlled experiments. How on earth is this possible???? They haven’t written anything down all year!!!! So, do hamsters get quicker at finding their way through a maze – this group is building a magnificently complicated maze, know exactly what they’re doing and have taken on board ideas of repeats and controls. Wonderful. Another group is testing food preferences and is building an appropriately simple T-maze. A third is seeing if turns are made at random, or whether there’s a pattern – does turning left make the hamster more likely to turn right next time. Excellent.

Best of all, and one of my Key Performance Indicators (aarrrghhhh) of a successful lesson, they all look surprised and rather disappointed when I tell them it’s time to clear up. Is that really the end of the lesson? How has it gone so quickly?

The actual experiments take place on Friday….

The Lesson from the Black Lagoon….

As I’ve mentioned in previous burbles, one of my main projects this year has been to overhaul the KS3 scheme of work for the Year 7s (next year I hope to tackle the Year 8s). This has been a mammoth undertaking, far more work than I had originally envisaged, but has also been a huge amount of fun; I’ve loved teaching Year 7s for the first time in my career, and I’ve loved the creative aspect of creating new lesson plans and resources. Because KS3 Science is standardised across the year groups, it’s also been my cunning way of ensuring that this investigative approach is used by other teachers…

But at this time of year, with 6th form rapidly approaching study leave and PSAs to deliver, mark and moderate, and all kinds of other time consuming priorities, I had decided to leave any updating of the Element and Compounds topic until next year. And then I saw the first lesson on the olde scheme of work…

“Give out the packs with the periodic tables: discuss the periodic table and elements – what they represent and a basic idea of how they’re organised. Make sure students write down the definition of an element.”

… and I thought, I’m not doing that. No way. I can’t imagine a worse way of doing this. Sure, they have the information. They’ve written something down. But having a pack of information, writing something down, is not the same as knowing something. And knowing something is not the same as understanding it. And, worst of all, however you dress it up, it’s just dull dull dull. The lesson from the black lagoon.

So we did this.

After an introductory practical “circus” of elements and their properties, which I hadn’t changed from the original SoW, and which they got very excited about, (especially when they got to test the gas jar for the presence of oxygen to see whether the label was accurate, or whether I was lying), I talked a little bit about the history of elemental discovery. All these elements! All these properties!

Then I gave each pair one of these with some scissors

Periodic table cards for working it out a la Mendeleyev

a set of the first 20 element cards in the order that they were discovered. The cards had the atomic number (which I just called “weight”), the valency, and a brief description of the properties. They had to cut them out and try various ways of arranging the cards to see if anything interesting emerged. They were not allowed to do any research – they were not allowed to look at the Periodic Table in their planners. This prompted lots of good questions – what is valency? What do I mean by “weight”? And so on.

At this point it got quite full on. Some put them into piles based on their state of matter. But this didn’t really show anything interesting. What else could they do? Don’t put them into piles, for a start. Arrange all the cards face up and visible on the desk. They tried grouping them by valency, and although that saw the Noble Gases pop out in a nice, distinct collection, it also saw Sodium in with Chlorine. Not helpful. What else could they do? What would be the simplest thing to do?

I was rushing from group to group thinking, next time, they’ll do it in 4s, not pairs!

But then they started to crack it. They starting putting them in order of weight and, joy of joys, they started seeing it. And they got VERY excited. Look! These ones have all the same properties! And so do these! And these! Look! The valency goes 0, 1, 2, 3, 4, 3, 2, 1….

What’s going on????? It was one of those glorious, eureka moments that make teaching better than any other job on the planet.

At this point I talked about Mendeleev. How he had an element named after him. How he transformed our understanding of Chemistry. How he was a genius. And how they had just done exactly what he did.

And there was something else he did, too.

I then handed out these

Periodic Table with gaps for predicting properties

Periodic Tables with 3 elements blanked out. Tell me about these elements, I said. You don’t know what they are, you’ve probably never heard of them, but you can still tell me something about them. At first they weren’t quite sure what I meant. Did I want them to find out the names? No, I don’t want you to do any research. I don’t want you to find out anything. Just tell me something about those elements.

And then they twigged. Element number 1, must be a soft metal that reacts readily with water and has a valency of 1. Element number 2 must be a coloured, poisonous gas with a valency of 1. Element number 3 must be a colourless, odourless, completely unreactive gas with a valency of 0. Bingo! Meet rubidium, bromine and krypton.

There are things I’ll change the next time I do it, but as an exercise, it works. They figure it out, they understand it, they can use it to make predictions… next time, we might write some of it down…