Introductions

First, a very quick quick word on the Year 8 Wheat and Weeds experiment. Well, they really enjoyed the freedom and autonomy of designing their own way of answering the question. 8 different group, 8 different approaches – but all highlighting an understanding of controls, measurements, repeats…. with no input from me other than posing the question and providing the apparatus. The contrast between a class dutifully following a series of instructions, and a class where individuals work it out for themselves, couldn’t be starker. So I was pleased with that bit…

…stay tuned to see if they actually get any results…!

I’ve burbled before on the importance of how you start a lesson. Some way to grab their attention, spark their curiosity or imagination, get them thinking…

Two examples from the last week.

Example 1

Biotechnology with Year 13. Immobilised enzymes. NB if you don’t do this practical…

Immobilised enzymes

…put it to the top of your priority list for New Things I Will Do Next Year – it’s a 24 carat guaranteed gold medal winner – students are utterly delighted with the little alginate beads of entrapped enzyme, and, better still, it works 100% reliably – starch is successfully hydrolysed to detectable levels of reducing sugar – (let me know if you need the technical details…).

I’ve done this for years, but wanted a slightly different beginning, partly just for a change, partly to try and emphasize/clarify a couple of the learning points.

So I gather them around my demonstration bench.

There’s a couple of cobs of maize, a bottle of amylase, and some random labels from Ready Food packages.

What’s the connection between these objects?

It’s an interesting reaction. Students used to me start passing the things around, reading the label on the bottle, looking closely at the food packaging. Students new to me, more used to being spoon-fed the answers, wait patiently to be told what to think.

But even the willing ones get a bit stuck, so it’s time for a hint (always hint, never tell them: always answer questions with questions – they need to work out the answer for themselves, even if they need a bit of help to get there). Read the food label really closely, I suggest.

Which they do. A couple of them spot it simultaneously. “Modified maize starch!” (it’s great, isn’t it? The equivalent of “aqua” on shampoo ingredients).

OK, so what’s the link?

And so we talk about maize being a great source of sugar because it’s so rich in starch. And can be grown in temperate countries. And that starch can be readily hydrolysed by the enzymes that your genetically modified bacteria produce in such vast amounts (which leads to an interesting side issue on another label on the product – “Contains no GMOs…”). And why enzymes are so attractive to industry. But how a big pot of starch + amylase negates two of these attractions – the ability to re-use them and the purity of the product…

… which leads perfectly into their Immobilised Enzyme procedure.

Example 2

Elements, Mixtures and Compounds with Year 7. I’ve already described the second lesson in this SoW at exactly this time last year – see The Lesson from the Black Lagoon – 28th April 2015 – but just had an additional idea for introducing the topic itself. I don’t think this is particularly brilliant or original (I imagine most Science/Chemistry teachers do something similar), but it certainly got them thinking.

Time to project a picture.

Democritus-400

Who’s this?

Of course, they have no idea. Never mind. He was Democritus. Ancient Greek. Ancient Greeks didn’t do experiments, but boy did they like thinking. I produce a bit of lead and a pair of scissors. And cut the lead in half. And cut it in half. And cut it in half. Can I keep doing this? Forever? Assuming very very sharp scissors and very very good eyesight, is lead infinitely divisible?

The thought definitely grabs them and sparks discussion. Yes, say some. No, say others.

I tell them that Democritus was in the No camp. And coined the word “Atomos” – indivisible. They like this – they’ve heard of atoms and now they know where the word comes from.

A clump of molymods seals the deal. Look – imagine these are atoms of lead. In a clump of lead. I can divide them. And divide them. Until I’m left with… and they see the final, indivisible atom.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s