Tales From The Preproom @magentatechnician - Tumblr Blog

The Other Lavoisier

If you're remotely interested in the history of chemistry you will have heard of Antoine Lavoisier (Wikipedia). He's best known today for the discovery of oxygen* and for introducing measurement into chemistry.

You'll often find articles about Lavoisier illustrated with this picture:

To whom does that mysterious hand belong? Well, the full image is this:

The standing figure is Antoine's wife, Marie-Anne. You probably haven't heard much about her (for the usual sexist reasons), but she made as important a contribution to chemistry as her husband.

The Lavoisiers are a fine example of teamwork in research: they worked alongside each other in the lab, Marie-Anne keeping meticulous notes. She wrote up and illustrated their publications (of course, they appeared in public with only his name on them). They were able to keep up with publications from the English-speaking world because Marie-Anne translated them into French.

The life stories of both the Lavoisiers outside of chemistry are fascinating - go and look them up. And if you're ever giving a presentation or making a display on the history of chemistry, do mention Marie-Anne.

Worth a listen: BBC Radio's Madame Lavoisier's Translation of Oxygen.

*Yes, I know about Priestley. He made the observations; Lavoisier interpreted them correctly.

#chemistry #women in stem #women in chemistry #history of science #history of chemistry

School chemistry vs. Real chemistry

Recently I’ve become interested in the concept of “microscale” chemistry and the philosophy of its approach to practical work in schools. It’s had a lot of publicity in the relevant bits of social media over the last years, and the reaction to it seems to have been largely positive. There are books dedicated to it, and training courses.

I don’t think it’s the right approach. I don’t think it’s enough for students simply to “do practicals” - there has to be a deeper philosophy to it, or we might as well stick to demonstrations and videos. The approach has led to great ideas (I wrote about one here), but overall I’m sceptical. The detailed critique will have to wait, however, because…

Working as a technician after years as a researcher in industry has convinced me that there is a difference between those who do chemistry and those who teach it, and that we need to bridge that gap. A line from the first article I linked to illustrates this:

“One pioneer of Microscale Chemistry in the UK, Stephen Breuer said, why make 5g of an organic chemical, use 0.1g for spectra and experiments and throw 4.9g away?”

Well. As an organic chemist I never tired of simply making compounds. The satisfaction of seeing that white powder in your flask never dimmed, and it was even more heart-warming if you could take the brown sludge from your first stage and purify it to a crystalline solid. Every synthetic chemist knows that feeling.

If we want some of our students to go on to be professional chemists then the joy of simply making stuff will draw them in. It doesn’t have to be organic - making copper sulfate is always popular, and suitable for students under 16. Growing crystals is a great activity for science clubs (I present the alum and chrome alum crystals I made for, ahem, research purposes). But you have to be able to see it, to have enough to scrape into a vial and weigh, and stick a label on it. Making a few mg, a thin layer on a filter paper, for analysis just won’t cut it. Doing chemistry on a larger scale also makes it easier for inexperienced chemists.

I can’t remember what drew me to chemistry in the first place. I ended up wanting to do it for a living because I found designing and making compounds interesting, challenging and fun. With properly designed practical work we can give today's school students a taste of that. We just have to make sure that teachers and those who write the syllabuses get it too.

P.S. This isn’t the only example of a disconnect between school chemistry and chemistry as she is practised in the real world. More examples to follow if I get the chance.

#chemistry #school science technician #education in chemistry

That's just wrong!

Here's an excerpt from the GCSE Chemistry textbook we use in our school.

There are several crimes against chemistry in these statements. However, sometimes you have to simplify in order for students to understand the general idea, so there are always going to be lines in textbooks that make an experienced chemist mumble "I think you'll find it's a bit more complicated than that".

What makes me uneasy is when we teach stuff that's not just inaccurate but incorrect. Take the third bullet point, "The liquids become more viscous". The trouble is, they don't. To the unassisted human senses the viscosity of liquid hydrocarbons barely changes from hexane (6 carbon chain) to barbecue lighter fluid (11 to 14 carbons). You certainly wouldn't be able to measure any difference in a school lab. Motor oil (18 to 34 carbons) is a bit gloopy (to use a technical term) but still flows easily. If the carbon chains get slightly longer (20 to 40) you get waxes.

This evidence-free assertion has been taught in school chemistry forever. It may be plausible, but it's still wrong, and I can't believe I'm the first person to notice. It's far from the only example in school science. There are plenty in chemistry, but my favourite(!) is from biology - the way we teach the inheritance of eye colour is spectacularly bad.

This matters. We're teaching students "facts" that are easily disproved. We're making them do practicals that don't work because they haven't been tested or the instruction sheets are badly written (there's a whole book there, let alone a blog post). And if we aren't trustworthy, why shouldn't students be sceptical about science?

#chemistry #education in chemistry #bad science

Reduction of copper(II) oxide with hydrogen - a less scary method

"Reduction of metal oxides" is a common topic on school chemistry syllabuses. You might find it discussed under the reactivity series. If the course has a more "applied" aim, there might be a section on metal refining.

When it comes to practical examples, the most common one we let students have a go at is the reduction of copper(II) oxide with charcoal / carbon (example here). If done properly it's visually effective - a black mixture generates flecks of orange copper metal. I've also seen it done with:

Copper(I) oxide: not very effective - an orange oxide gives an orange metal.

Lead(II) oxide: striking - gives shiny blobs of liquid lead metal, but generally avoided because of the safety problems of working with lead.

Iron(III) oxide: the red oxide converts to grey metal, but when you remove the heat it re-oxidises back to the oxide.

There's an alternative experiment which is less common in schools: using hydrogen (or methane) as the reducing agent. I like the idea of this one, as hydrogen is potentially much more environmentally-friendly than carbon, and "green" chemistry is something we should be talking to students about.

A typical procedure (from the Royal Society of Chemistry) is here. However, the idea of creating a fire hazard by opening a hydrogen cylinder (or mains gas tap) in a school lab has always made me jumpy. Is there a better method? CLEAPSS have come up with a small scale version*, and I gave it a go.

The set up:

Hydrogen is generated by reacting zinc chunks with sulfuric acid. The heat source is an ethanol spirit burner, and the reaction vessel is a glass pipette.

The result:

I also tried lead(II) oxide, mixed lead oxide ("red lead") and iron(III) oxide.

It took 2 minutes of heating to produce these results. And because there is a stream of hydrogen passing over the metal while it cools, the iron doesn't re-oxidise. I managed to do five reactions (lead(IV) oxide wasn't so good) with one hydrogen generator.

In conclusion: this is a safe and visually effective method of using hydrogen for reducing metal oxides in a school lab. There are no special chemicals or expensive equipment required, and I recommend that you let your students have a go!

*Membership required

#chemistry #education in chemistry #small scale

Giant silver mirror

A tested and guaranteed-to-work procedure. Apologies for the formatting.

This demonstration uses a 250cm3 round-bottomed flask. It can be scaled up or down, and any glassware could be used.

Equipment

250cm3 round-bottomed flask

250cm3 beaker

Measuring cylinders – 50cm3, 25cm3, 10cm3

Dropping pipette

Glass rod

Distilled water in a wash bottle

Chemicals

Silver nitrate solution, 0.1M

Potassium hydroxide solution, 0.8M

Glucose solution: 1.1g in 25cm3 water

Ammonia, concentrated

Procedure

Place 40cm3 of silver nitrate solution in a 250cm3 beaker.

Add 20cm3 of potassium hydroxide solution. A dark brown precipitate will form.

Add ammonia dropwise, with swirling, until the precipitate just redissolves.

Pour the solution into the round-bottomed flask.

Add 3cm3 of glucose solution. Stopper the flask.

Swirl the flask so that the solution wets the whole inside surface. A silver mirror should start to form in 2-3 minutes.

Once a satisfactory mirror has formed pour the solution down the sink with the tap running. Rinse out the flask with distilled water and pour the washings down the sink.

Technician notes

Clean the reaction vessel carefully beforehand: use detergent and a brush, rinse with water, rinse with dilute nitric acid and finally wash it out with distilled water.

The deposited silver can be removed with dilute nitric acid: loosen the deposit by filling the flask with acid (over several days), then scrubbing.

Experiment Hazard Assessment

Experiment: Giant silver mirror

Reference: D-39

Chemical hazards

Silver nitrate (0.1M)

Irritant (skin, eyes)

CLEAPSS Hazcard 87

Recipe Book 77

Potassium hydroxide (0.8M)

Corrosive (skin, eyes)

Wear goggles

CLEAPSS Hazcard 91B

Recipe Book 71

Glucose solution

Not classified as hazardous

CLEAPSS Hazcard 40C

Ammonia (concentrated)

Causes severe skin burns and eye damage.

May cause respiratory irritation.

Very toxic to aquatic life.

Wear goggles.

CLEAPSS Hazcard 6

Other hazards/precautions for teachers and technicians

Work in fumecupboard. Wear goggles and gloves.

#education in chemistry #silver mirror #school science technician

What is the point of practical chemistry in schools?

In which I attempt to do myself out of a job…

When we learn science in school we do practical work. It’s seen as a valuable part of the process, supplementing the classroom work and bringing the subject to life. In the UK we do rather a lot of it compared to other countries, and many educators would argue that we still don’t do enough. Ask any adult what they remember about their science lessons at school from years previously and practical work will feature pretty strongly in their memories. Sometimes it’s the only memory.

And yet… There are good arguments for getting rid of practical work. Most obviously there is cost. You need all the resources that the English department has, plus chemicals, glassware and other equipment. You need extra staff (we technicians might not be paid much but we still cost money). In some countries schools don’t have technicians, so teachers need to do the job - spending time that they’re not teaching. There are classroom management issues (do you really trust that class to use Bunsen burners without injuring themselves?).

Crucially there is the question: what do students actually learn in practical lessons? In my experience many students see practicals as play time, and switch off from learning. Others focus on the practical work and lose the connection with the learning objective it’s supposed to reinforce. Under the curriculum in England at the moment it’s very tempting to do the Required Practicals just to tick the box, rather than treating them as a learning experience.

Surely we’d be better off doing demos and watching videos? No opportunity for students to foul up and you can repeat if necessary. Instead of spending a lesson failing to collect data you can present them with a pristine set of data, and you can spend time getting them to plot the graph properly.

Before I go and collect my P45, here’s the alternative: we teach students how to do practical work as an end in itself. This starts with drilling safe practice until it becomes instinctive - wearing safety glasses at all times, standing up and following instructions to the letter. This isn’t new - many schools issue “Bunsen Burner Licenses” to their Year 7’s when they are judged to be able to use them safely. We can move on to handling glassware and equipment properly and confidently. They need to handle chemicals safely - measuring them out without spilling (and clearing up if they do), recapping bottles as soon as possible, and generally treating potentially dangerous substances with respect. It should be second nature for them to pay attention to their experiments and to record their data properly (as per the instructions).

What’s the point of this change in emphasis? Even if students don’t go into science after leaving school we are giving them skills and an attitude that are useful in many fields. For those going on to university science courses or technical apprenticeships they will have the confidence to get on with and enjoy their practical work immediately.

This is a huge area that needs a more extensive treatment than this piece, with examples and references. But I hope it starts a debate.

Next time: why we are letting down our students with rubbish practicals (with examples).

#school science #school science technician #chemistry #practical skills

An alchemical short story

My first attempt at writing fiction since I left school. What do you think?

Magical Accidents

Capella Trimble, the potions technician at Newton School of Magic, set her mug of tea down on her desk and tried to ignore the huge pile of washing up festering in the sink. It would have to be done soon, of course: there weren’t enough clean alembics in the cupboard, and dirty cauldrons could develop a life of their own. She was still jumpy about the incident a couple of weeks ago, when an (unknown) magical mixture had caused a wall of purple flame to leap out of the sink.

The washing-up fairy who used to do such a wonderful job had been moved to the kitchens, with no sign of a replacement. Luckily they had finally been allowed to recruit an apprentice. Isis had already proved her worth - with her safety training fresh in her mind she had extinguished the sink fire before any damage was done.

Capella took the chance of five minutes’ peace on a Thursday afternoon to check the teachers’ schedules for next week. She flicked her wand at the snakeskin-clad notebook on her desk. It flipped open, she muttered “Deinde septimana”, and the timetable appeared on the page. Rigel and Freya: nothing, as usual. Thor and Procyon: full schedule. Thank you. Theophrastus: Monday and Tuesday only. Oh well, better than nothing.

She scanned the individual entries. Better order some more Eye of Newt, she thought. The right sort of newt was now a protected magical species and, while there was an alternative, it had to come from Romania, you needed twice as much as you used to, and the supplier could never guarantee delivery.

Isis had finished setting up her apparatus for making deadly nightshade extract and was now looking at her notebook. “Anything interesting for next week?” she called out.

“Well… Capella answered. “It looks like there’s nothing to worry about. The Fifths are all doing Identifying Unknowns - there’s a set of incantation books and colour charts for that. The Sixths are starting Alchemy - that could be messy, but not till the week after.”

“Have we got enough lead for Alchemy?”

Capella’s face broke into a half-smile and her amused tone was mixed with exasperation. “My predecessor stocked up enough lead sheet to redo the roof. There’s enough to outlast both of us. In fact,” she mused grimly, “I’ll offer it to Maintenance the next time we have a leak.”

She carried on reading. “Thor wants to do the Flamel demo,” she sighed. “Mmm?” Isis prompted. “It’s supposed to be a demo of gold-making. It never works properly - it usually ends up as a red solution instead of gold particles.”

Something clicked in Isis’s brain. “Hang on - I read about that the other day - a new method. Can I see if I can get it to work?”

“We’re quiet tomorrow afternoon. See what you can do.”

* * *

At tea time on Monday morning Isis proudly announced, “That Flamel demo works! It took a few attempts, but I got there in the end.”

Capella wandered over to Isis’s bench and inspected the flasks sitting there. One had clearly refused to work, one had overflowed, one had produced a splat of bright green sludge, and one was hypnotically beautiful: a cascade of gold flecks glinting in a colourless liquid.

“Well done! That’s the best one I’ve ever seen! What did you do differently?”

“Not much. It’s very similar to the old method, but you do have to follow the procedure exactly.”

“OK. Write it up and Thor can try it on Wednesday.”

* * *

On Wednesday afternoon Capella returned from a hurried early lunch to find a pale Isis fidgeting in the prep room. “What’s happened?”

The words of the reply came tumbling out. “Thor’s Flamel demo… Something went wrong! He said it got a bit frisky… so he poured it down the sink… It summoned a sprite… I think we’ve found that missing mini-wand.”

Capella’s muttered curse was still loud enough to coax a brief red flame from her wand. “What's he done with the class?”

“Took them off to lunch early.”

“And left us to deal with the mess.” Another flicker of red flame.

Capella softened her expression and spoke in a calmer tone to the frightened young apprentice in front of her. “It wasn’t your fault. I’d bet my wand the great lump didn’t follow the procedure… again. What’s the sprite doing?”

“It was hanging in the air above the sink when I looked. It looked like it was asleep. I don’t think the summons worked properly.”

“Thank the gods for that. Look, you go and get some lunch. I’ll clean up.”

A grateful Isis scampered off. Capella picked up the safety spells book and a pair of dragonskin gloves. She dismissed the rapidly-cooling mug of tea on her desk from her mind and strode off down the corridor. As she locked the door a bubble rose from the sink and burst with a puff of green smoke.

#school science technician #short fiction #alchemy #school of magic

Unbreakable glassware

A follow-up to my post from ages ago on my lab amigurumi. Here are the patterns.

The conical flask design is courtesy of Crafty Shanna. The other designs are based on that pattern and the patterns are below (British style). I used double knitting wool with a 4mm hook.

Have a go and let me know how you get on!

Beaker

Round 1: ch2, 6dc in 2nd st from hook. Or 6dc in magic ring.

Round 2: 2dc in each st around (12sts)

Round 3: *dc1, 2dc in next st.* Repeat around (18sts)

Round 4: *dc2, 2dc in next st.* Repeat around (24sts)

Round 5: *dc3, 2dc in next st.* Repeat around (30sts)

Round 6: *dc4, 2dc in next st.* Repeat around (36sts)

Round 7: *dc5, 2dc in next st.* Repeat around (42sts)

Round 8: *dc6, 2dc in next st.* Repeat around (48sts)

Round 9: dc48 in back loops only

Round 10: dc48

Round 11-22: dc48

Round 23: dc48 in back loops only

Round 24: *dc6, dc2tog.* Repeat around (42sts)

Round 25: *dc5, dc2tog.* Repeat around (36sts)

Round 26: *dc4, dc2tog.* Repeat around (30sts)

Round 27: *dc3, dc2tog.* Repeat around (24sts)

Round 28: *dc2, dc2tog.* Repeat around (18sts)

Round 29: *dc1, dc2tog.* Repeat around (12sts)

Stuff firmly

Round 30: dc2tog around (6sts)

Weave the thread into the stitches and pull the hole closed

Starting with a slipknot join white yarn in the front loop of the 1st of round 23.

Round 1-9: dc48

Round 10: *dc7, 2dc in next st.* Repeat around (56sts)

Sl st into 1st st of next round. Fasten off.

Weave in loose ends. Embroider eyes and a mouth, and/or measurement markings.

Round-bottomed flask

Round 1: ch2, 6dc in 2nd ch from hook.

Round 2: 2dc in each st around (12sts)

Round 3: *dc1, 2dc in next st.* Repeat around (18sts)

Round 4: dc1, 2dc in next st, dc2, 2dc in next st, dc3, 2dc in next st, dc2, 2dc in next st, dc3, 2dc in next st, dc2 (23sts)

Round 5: dc1, 2dc in next st, dc3, 2dc in next st, dc3, 2dc in next st, dc3, 2dc in next st, dc3, 2dc in next st, dc3, 2dc in next st, dc1 (29sts)

Round 6: dc4, 2dc in next st, dc5, 2dc in next st, dc5, 2dc in next st, dc5, 2dc in next st, dc5, 2dc in next st (34sts)

Round 7: dc4, 2dc in next st, dc5, 2dc in next st, dc6, 2dc in next st, dc6, 2dc in next st, dc6, 2dc in next st, dc2 (39sts)

Round 8: dc6, 2dc in next st, dc8, 2dc in next st, dc9, 2dc in next st, dc9, 2dc in next st, dc3 (43sts)

Round 9: dc3, 2dc in next st, dc9, 2dc in next st, dc10, 2dc in next st, dc10, 2dc in next st, dc7 (47sts)

Round 10: dc6, 2dc in next st, dc14, 2dc in next st, dc15, 2dc in next st, dc9 (50sts)

Round 11: dc9, 2dc in next st, dc15, 2dc in next st, dc16, 2dc in next st, dc7 (53sts)

Round 12: dc5, 2dc in next st, dc16, 2dc in next st, dc17, 2dc in next st, dc12 (56sts)

Round 13: dc12, 2dc in next st, dc27, 2dc in next st, dc15 (58sts)

Round 14: dc17, 2dc in next st, dc40 (59sts)

Change to white yarn.

Round 15-17: dc59

Round 18: dc40, dc2tog, dc17 (58sts)

Round 19: dc15, dc2tog, dc27, dc2tog, dc12 (56sts)

Round 20: dc12, dc2tog, dc17, dc2tog, dc16, dc2tog, dc5 (53sts)

Round 21: dc7, dc2tog, dc16, dc2tog, dc15, dc2tog, dc9 (50sts)

Round 22: dc9, dc2tog, dc15, dc2tog, dc14, dc2tog, dc6 (47sts)

Round 23: dc7, dc2tog, dc10, dc2tog, dc10, dc2tog, dc9, dc2tog, dc3 (43sts)

Round 24: dc3, dc2tog, dc9, dc2tog, dc9, dc2tog, dc8, dc2tog, dc6 (39sts)

Round 25: dc2, dc2tog, dc6, dc2tog, dc6, dc2tog, dc6, dc2tog, dc5, dc2tog, dc4 (34sts)

Round 26: dc2tog, dc5, dc2tog, dc5, dc2tog, dc5, dc2tog, dc5, dc2tog, dc4 (29sts)

Round 27: dc1, dc2tog, dc3, dc2tog, dc3, dc2tog, dc3, dc2tog, dc3, dc2tog, dc3, dc2tog, dc1 (23sts)

Round 28: dc2, dc2tog, dc3, dc2tog, dc2, dc2tog, dc3, dc2tog, dc2, dc2tog, dc1 (18sts)

Round 29: back loops only. *dc1, dc2tog*. Repeat around (12sts). Stuff firmly.

Round 30: dc2tog. Repeat around (6sts). Weave the thread into the sts and pull the hole closed.

Starting with a slipknot join white yarn in the front loop of the 1st st of round 29.

Round 1-6: dc18

Sl st into 1st st of next round. Fasten off.

Weave in loose ends. Embroider eyes and a mouth.

Test tube

Round 1: ch2, 6dc in 2nd st from hook. Or 6dc in magic ring.

Round 2: 2dc in each st around (12sts)

Round 3: dc, 2dc in next st, dc2, 2dc in next st, dc, 2dc in next st, dc2, 2dc in next st, dc, 2dc in next st (17sts)

Round 4: dc2, 2dc in next st, dc3, 2dc in next st, dc3, 2dc in next st, dc3, 2dc in next st, dc2 (21sts)

Round 5: dc3, 2dc in next st, dc6, 2dc in next st, dc6, 2dc in next st, dc3 (24sts)

Round 6: dc10, 2dc in next st, dc13 (25sts)

Round 7-25: dc25

Round 26: *dc2tog, dc3.* Repeat around. In back loops only (20sts).

Round 27: *dc2tog, dc2.* Repeat around (15sts). Stuff firmly.

Round 28: *dc2tog, dc1.* Repeat around (10sts).

Round 29: dc2tog. Repeat around (5sts).

Weave the thread into the sts and pull the hole closed.

Starting with a slip knot join white yarn in the front loop of 1st st of round 26.

Round 1-12: dc25.

Sl st into 1st st of next round. Fasten off.

Weave in loose ends. Embroider eyes and a mouth.

#chemistry toys #crochet #amigurumi

Rust

One of my many bugbears with school science education is that some of the suggestions out there for lab work are theoretical rather than experimental: whoever has written them down has not actually gone to the bother of trying them out in real life. When you do them with a class they don’t turn out as you might expect, and as a result are pretty useless for teaching.

Here’s an example, from the Royal Society of Chemistry, no less: What causes iron to rust? “Everyone knows” that iron rusts faster in the presence of salt (sodium chloride), but when we’ve tried this experiment at school we’ve found consistently that there is less corrosion in salty water than plain water. However, in the real world, iron really does rust incredibly quickly in salty conditions. Perplexing.

So I did an investigation. As in the procedure linked above I dropped some degreased nails into plain water, water with a spatula of salt dissolved, and boiled water. Just for the hell of it I also compared tap water (from a hard water supply) and distilled water. I didn’t bother with a drying agent - that one behaves itself. Here’s the photo of the start of the experiment:

After one day the nails in plain water had started to rust, the ones in boiled water were clean - and so were the ones in salt water. So I set up a second set of tubes with different concentrations of salt: 0.1% w/v, 0.5 M, 1 M, and concentrated (brine). I left them to stew for two more days, and here are the final photos:

As you can see the dilute salt solutions are behaving as expected, but brine seems to prevent rusting! I will do some digging and see if I can find an explanation.

At least we’ve found a reason for the students’ results, and we’ll hand out salt solution rather than getting them to make their own in future.

EDIT: according to this iron doesn’t corrode in brine because there’s no oxygen in solution. Makes sense.

#chemistry #Royal Society of Chemistry #rust #experiment #bad science #education

This is what makes science technicians happy.

#school science technician #trolley

Glassware amigurumi

This is my attempt at creating some unbreakable glassware using the power of crochet, and I have to say I’m fairly pleased. I found the pattern for the conical flask here (thank you Shanna) and I used it as the basis for the beaker.

I used double knitting wool and a 4mm hook and ended up with toys of a reasonable size (compare with the Lego minifigures in the photo).

So, the patterns (written in the UK style):

Conical flask

Round 1: ch2, 6dc in 2nd st from hook. Or 6dc in magic ring.

Round 2: 2dc in each st around (12sts)

Round 3: *dc1, 2dc in next st.* Repeat around (18sts)

Round 4: *dc2, 2dc in next st.* Repeat around (24sts)

Round 5: *dc3, 2dc in next st.* Repeat around (30sts)

Round 6: *dc4, 2dc in next st.* Repeat around (36sts)

Round 7: *dc5, 2dc in next st.* Repeat around (42sts)

Round 8: *dc6, 2dc in next st.* Repeat around (48sts)

Round 9: dc48 in back loops only

Round 10: dc48

Round 11: *dc6, dc2tog.* Repeat around (42sts)

Round 12-13: dc42

Round 14: *dc5, dc2tog.* Repeat around (36sts)

Round 15-17: dc36

Round 18: *dc4, dc2tog.* Repeat around (30sts)

Round 19-20: dc 30

Round 21: *dc3, dc2tog.* Repeat around (24sts)

Round 22: dc24

Round 23: *dc2, dc2tog in back loops only.* Repeat around (18sts)

Round 24: *dc1, dc2tog.* Repeat around (12sts)

Stuff firmly

Round 25: dc2tog around (6sts)

Weave the thread into the sts and pull the hole closed

Starting with a slipknot join white yarn in the front loop of the 1st of round 23.

Round 1: dc24

Round 2: *dc2, dc2tog.* Repeat around (18sts)

Round 3-4: dc18

Round 5: *dc4, dc2tog.* Repeat around (15sts)

Round 6-10: dc15

Sl st into 1st st of next round. Fasten off.

Weave in loose ends. Embroider eyes and a mouth, and/or measurement markings.

Beaker

Round 1: ch2, 6dc in 2nd st from hook. Or 6dc in magic ring.

Round 2: 2dc in each st around (12sts)

Round 3: *dc1, 2dc in next st.* Repeat around (18sts)

Round 4: *dc2, 2dc in next st.* Repeat around (24sts)

Round 5: *dc3, 2dc in next st.* Repeat around (30sts)

Round 6: *dc4, 2dc in next st.* Repeat around (36sts)

Round 7: *dc5, 2dc in next st.* Repeat around (42sts)

Round 8: *dc6, 2dc in next st.* Repeat around (48sts)

Round 9: dc48 in back loops only

Round 10: dc48

Round 11-22: dc48

Round 23: dc48 in back loops only

Round 24: *dc6, dc2tog.* Repeat around (42sts)

Round 25: *dc5, dc2tog.* Repeat around (36sts)

Round 26: *dc4, dc2tog.* Repeat around (30sts)

Round 27: *dc3, dc2tog.* Repeat around (24sts)

Round 28: *dc2, dc2tog.* Repeat around (18sts)

Round 29: *dc1, dc2tog.* Repeat around (12sts)

Stuff firmly

Round 30: dc2tog around (6sts)

Weave the thread into the stitches and pull the hole closed

Starting with a slipknot join white yarn in the front loop of the 1st of round 23.

Round 1-9: dc48

Round 10: *dc7, 2dc in next st.* Repeat around (56sts)

Sl st into 1st st of next round. Fasten off.

Weave in loose ends. Embroider eyes and a mouth, and/or measurement markings.

Hopefully this all makes sense.

The next projects will be test tubes and round bottomed flasks, but working those out is going to be a little tricky.

#chemistry #glassware #amigurumi #crochet #science toys #chemistry toys

Gold

Like most people my experience of gold is almost completely limited to jewellery. I've never done any chemistry with the metal or it compounds.

However, gold's role in human history cannot be overstated. It was one of the first metals to be discovered - its lack of reactivity means that it can be found in its elemental form on or close to the surface of the earth. Its properties (appearance, scarcity, malleability and apparent incorruptibility) have led to it being used to make precious objects and as currency for millennia. Wars have been fought and people have died over it.

The point of this blog post is to point out one of its more practical and positive uses. Researchers have long been interested in the properties that gold has when its particles are really small (we're talking nanometres - millionths of a millimetre). To cut a long story short: completely different to the bulk material. BBC Radio 4's Inside Science covered one possible application in cancer treatment. It's worth a listen, and follow the links if you want to discover more about gold nanoparticles.

As mentioned in the programme, the gold being used is coloured... green. The programme makers couldn't resist the reference to a classic comedy show, and neither can I. If you've never heard of Blackadder, here's a good place to start. By the way, the two writers on this series were Richard Curtis and Ben Elton. Curtis went on to write, amongst others, Love Actually and The Vicar of Dibley. Elton’s future CV is similarly disappointing.

Another reference I can't resist is, well, Golden Green. Allow me to indulge in a little nostalgia for The Wonderstuff (I’m showing my age now).

#gold #metal #element #nanoparticles #bbcinsidescience #cancer #blackadder #wonderstuff

The Periodic Table

If you haven't read Primo Levi's "The Periodic Table" I strongly recommend that you do. His memoir of his career as a chemist, and of his life as an Italian Jew (including being sent to Auschwitz), was a striking and unique reading experience for me.

Each chapter is based on the theme of an element from the Periodic Table. Inspired by this, and because being under COVID-19 lockdown means that there's very little tech stuff to comment on, I'm going to write some posts on the elements that I have encountered in my working life. I've counted 46 of these, so there's plenty to go on. Hopefully, like Levi, I can amuse and make you think.

#periodic table #primo levi

What technicians really want

Another contribution to Undercover Technician - this one from the heart.

If money were no object I would like a bigger prep room. It would be big enough to have desk space for each technician, including a computer. The benches would have room for prepping, storing equipment temporarily when it comes back, and even for conducting trial experiments at the same time. There would be enough floor space for as many trolleys as we need, loaded and ready to go. Alas, there would not be enough room for students to work.

#school science technician #undercover technician #prep room

Undercover Technician: Covid-19

The Royal Society of Chemistry’s Education in Chemistry website have posted their latest Undercover Technician column. This month’s subject is school closure in the UK due to the coronavirus-related lockdown. Some of my offering has made it. If you’re interested, here’s my original submission.

Our experience of Covid-19 shows the fast-changing nature of the situation.

We are an independent boarding school. One of our overseas students (who had been quarantined due to suspected symptoms) returned home early. Their parents later notified the school that they had tested positive. The result was that we went into work on Thursday March 19th to be told that the school was closing immediately and we were being sent home. We spent the rest of the day doing a truncated end of term shut down and went home, never to return.

It was a shock to finish so abruptly, but the warning signs were obvious. In the aftermath there was a little bit to do at home. I’ve been checking email much more frequently than during a normal school holiday, and I’ve had my first experience of signing an invoice with a laptop trackpad rather than a pen.

The realities of this truly novel experience are sinking in. We have now been placed on furlough, with an end date of May 31st – although, of course, no-one can be certain of that. Our HoD has donated gloves to the NHS. Technicians and teachers are keeping in touch through social media. It’s good to share gossip and jokes during this time of isolation. I’m still feeling the love for chemistry and I’ve been offering my consulting services to the teachers as they plan their long distance teaching for next term. One teacher has already discussed a home DNA extraction practical.

In the meantime I’m trying to help my own children with their schoolwork. We’ve made distilled water, red cabbage indicator and a bouncing egg (it didn’t bounce). I’ve tried some extension work – “The Science of Doctor Who” on BBC4 counts, doesn’t it?

#royal society of chemistry #rsc #education in chemistry #covid-19 #undercover technician #school science technician

How to start a technician fight

When you encounter science technicians in internet discussion groups there are some topics that are hardy perennials. I'll write about others in future entries, but today I'm going to talk about pipettes.

Disposeable (polyethylene) Pasteur pipettes are used in wet labs all over the world. You can buy a pack of 500 unsterilised 3ml ones for about £5 + VAT (UK) from school suppliers. In school labs they are a very good tool for transferring small quantities of liquid from one place to another. The volume markings are surprisingly accurate, and when instructions say "dropwise" it's possible for even the most ham-fisted students to comply.

The question that arouses controversy: should these pipettes be re-used or binned? Re-use might seem the more environmentally-friendly and economic option, but... They take a lot of effort to clean. They have to be filled and emptied manually to rinse them out, and that can take several repetitions (try pipetting some coloured water and then see how many rinses with tap water it takes to get rid of the colour). Putting them in the dishwasher is no good, as water simply does not get inside. Many people overlook one aspect of all this washing up - it takes time, which does cost money (technician wages), and which could be used for doing something else.

How about keeping pipettes for use with specific liquids and solutions? Do you trust students to be careful enough not to use the same pipette for two different bottles, or not to scatter them across the room?

Glass pipettes are an alternative to plastic. One advantage is that they are easier to clean. However, there is a real safety issue. It's very easy students to break them while trying to push the teat in. Their general fragility means that you can get sharp edges easily, which are a danger to students and technicians. And when it comes to disposal they're not recyclable, meaning that they go to the same landfill as plastic pipettes.

We can worry too much about the environmental impact of waste plastic, believe it or not. In a country like the UK with an advanced municipal waste-disposal system, binned pipettes will end up in landfill, not contaminating the general environment.

In conclusion: take the least-worst option, carry on using your plastic pipettes, and bin them.

#school science #pasteur #pipette #technician #recycling #waste disposal

Inspiration, and the perils of thinking too much

On a Facebook group for the parents of children with autism one particular post caught my eye. One parent was describing her son’s thought processes: he was prepared to argue that fossil fuels are actually renewable, because organic life now will one day be converted into fuel. Like many autistic people he clearly sees the world from a slightly different point of view. It got me thinking – where do our new ideas in science come from, and what do we do when we get them?

There’s no rhyme, reason or logic when it comes to inspiration. Great ideas can pop into your head from anywhere. It helps to be prepared of course. The more you know, the more likely it is that you have enough random facts swimming around in your subconscious that a few of them will be able to link up and give you a lightbulb moment.

When it happens, what next? You need to go and do some research – see what’s in the academic literature. You’re quite likely to find that someone has already had the same thought and followed it up. Oh well.

But say you can’t find anything in the literature. It looks like you really have thought of something new. Now you need to bounce your idea off someone else. Frustratingly they may well be able to spot the glaring holes in your reasoning, or to come up with a different interpretation of that weird thing that you noticed.

Or, they can’t spot any problems and your hypothesis is not dead yet. Now you need to roll up your sleeves and test it. What experiments do you need to do? The probability is that you will draw a blank. However, occasionally, just occasionally, one of your many bright ideas will survive all of the tests that you can throw at it and you will have come up with something genuinely new. Even if that doesn’t happen you might still notice a strange result, which can be another source of inspiration, and off you go again.

You may have gathered this from what I’ve already said: scientific discovery is a tale of mostly failure and disappointment. But what gets you out of bed and into the lab every morning is the hope that you’re going to make a real discovery. It might only be a tiny contribution to a large research programme, a small piece in a gigantic jigsaw, but it’s your work. In my case the thrill of being the first person ever to prepare a particular compound never diminished (it’s not as impressive as it sounds – there’s a lot of room in “chemical space” and we’re never going to fill it). And don’t forget – scientific discovery is done by teams. You might not make a compound, but you might be the one to test it and see the unexpected and impressive results.

If you want to see how research is really done, by flawed and passionate human beings, not always motivated by the right reasons, try James Watson’s “The Double Helix” on the discovery of the structure of DNA. If you want to see the consequences of taking facts and applying (slightly) twisted logic to them, “The Hitch-Hiker’s Guide to the Galaxy” never grows old.

#science #inspiration #logic #research #the double helix #hitch hikers guide to the galaxy

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