Revision help: GCSE Chemistry - (F)

May 23rd, 2015

Filtration

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This is a pretty decent technique for separating a liquid from solid particles - sand and water for instance. It’s quick ‘n’ easy - simply pour your water/sand mixture into filter paper in a filter funnel, and leave it for a sec. The filter paper has lots of pores in it that are big enough to allow the water to pass through into the beaker below but are sufficiently small so the sand gets stuck, and so, is left behind.
Filtration is used widely in everyday life - for example, at the sewage works, the water companies use filtration to remove all the toenails, hairballs, and, baby alligators that get flushed down the toilet with the other waste before it starts its long passage through the main cleanup process!

References:

McDuell, B. Ed. (1988) Chemistry: GCSE Passbook - Keyfacts. Letts.

Prescott, L.M., Harley, J.P., Klein, D.A. Ed. (1996) Microbiology 3rd ed. Wm. C. Brown Publishers.

© Willow Science 2015

Vicky xx

Revision help: GCSE Chemistry - (D)

May 23rd, 2015

Decantation

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OK, so if you’ve got a mixture of an insoluble solid and a liquid (gold and water for instance), then you may be able to separate the two by slowly pouring off the liquid into a fresh beaker. This happens best if the solid is pretty dense, and so, settles in one big lump at the bottom of the flask.
A steady hand is needed here - so it’s best avoided if you’ve just found out that they’re serving boiled liver, steamed cabbage, and tripeballs in the school canteen for lunch - you have to pour very carefully!

Reference:

McElroy, M, & Sadler, J. Ed. (1990) Longman Reference Guides: GCSE Chemistry. Longman.

© Willow Science 2015

Vicky xx

May 14th, 2015

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Hmm, fancy a refill?

Now, I’m a pretty clean type-of-girl who would never even consider leaving the ladies’ without having a ‘good scrub’. So, you can just imagine my surprise, when recently, I read about how soap dispensers, in particular, the ones refilled by pouring fresh soap in, can become contaminated with microbes… bacteria such as Citrobacter, Serratia, and Pseudomonas… which can then, seemingly, thrive in the very stuff that’s supposed to kill them off, to then, possibly, go on and cause doom-and-gloom for any subsequent users (Pseudomonas, for example, are opportunistic pathogens - with Pseudomonas aeruginosa being a well known case).
Yes, a recent study has shown, quite clearly, that washing the hands with microbially-contaminated soap can actually, leave more microbes on your hands than were there to begin with before the wash, some of which, can then, be spread to any surfaces that you later touch!
All right, so this problem may not be all that widespread in nature… and it definitely, shouldn’t, put you off from washing your hands when you’re out-and-about in public… but, if you do feel concerned about this, then please, don’t negate personal hygiene… just remember to always, ‘go prepared’… and take with you, every time you leave the house, your own bottle of liquid soap (that’s been declared as ’safe’ through the constant monitoring for microbial contamination)… or, alternatively, you could just ‘sniff out’ places that provide ‘sealed-soap dispensers’ as, in the same scientific study, this type of unit was found to suffer less, from this type of problem.

References;

Murray, P.R., Rosenthal, K.S., Kobayashi, G.S., Pfaller, M.A. Ed. (2002) Medical Microbiology 4th ed. Mosby, Inc.

Zapka, C.A., Campbell, E.J., Maxwell, S.L., Gerba, C.P., Dolan, M.J., Arbogast, J.W., Macinga, D.R. (2011). Bacterial hand contamination and transfer after use of contaminated bulk-soap-refillable dispensers. Appl. Environ. Microbiol. 77(9):2898-2904.

© Willow Science 2015

Vicky xx

Science Stuff Newsletter

May 12th, 2015

ws-logo.JPGScience Stuff Newsletter

Spread the word… not germs

When it comes to spreading diseases - the hands are pretty bad - getting themselves everywhere - in and out of everything, they pick up microbes from one place before sticking them down basically, anywhere, you later touch - the toilet to that chicken salad baguette your about to have for lunch… for instance!
Hopefully, your teacher will show you all of this in action (if they haven’t done so already) by using the classic experiment where you get your unwashed hands and stick um on an agar plate for a sec, before incubating it for a week (medium heat), and see what’s grown - normally, you get a load of slime, mucus, and fur!
You repeat the experiment with washed hands, where, if things have gone to plan; you should get much less stuff growing.
This will show you just how important it is that you wash your hands regularly throughout the day, and, even more so, if you’re about to prepare or handle food.
You can never underestimate the amount of times that bacteria such as E. coli, can make the long perilous journey from your backside to your mouth to cause food poisoning if you’re not too careful - even if you wear latex gloves like those off of restaurants, cafes, and on supermarket fish counters - you’ll find you’re still not entirely safe. Yes, I know, these gloves are supposed to prevent this sort of thing from happening, but, if your hands are minging in the first place, then you can defo transfer bugs to the outer surface of the gloves while you’re actually putting them on - these germs can then get on to any food and surfaces that you then put your mitts all over - thus helping to spread disease and death around the place.
Yuk!!!

References:

Murray, P.R., Rosenthal, K.S., Kobayashi, G.S., Pfaller, M.A. Ed. (2002) Medical Microbiology 4th ed. Mosby.

Rönnqvist, M., Aho, E., Mikkelä, A., Ranta, J., Tuominen, P., Rättö, M., Maunula, L. (2014) Norovirus transmission between hands, gloves, utensils, and fresh produce during simulated food handling. Appl. Environ. Microbiol. 80(17): 5403–5410.

© Willow Science 2015

Vicky xx

Cancer Awareness - ‘Nutcare’

April 15th, 2015

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OK nuts - don’t neglect um, they’re there for a reason - mainly for reproduction… and something to do with hormones - great, especially since most of the time, they cause no problems, but occasionally… yes, cancer can happen. However, um being hidden away and stuff means that they often get forgotten about - but regular ‘nutcare’ is important - gentle inspection is a must - try and get used to how they feel - and yeah, go for it - make notes, draw diagrams, take photos… and even, jot down a few measurements just for future comparison. Get to know your way around them, understand their dynamics… their connection with the universe… what makes them tick, then, if owt goes wrong - you’ll be ‘on it’ straight away.
As for the question of ‘when and where’ to carry out a ‘nut inspection’ - well, this is always best done in a quiet place, a spot where you can give them your full attention - the bath, couch, or bed for instance - it doesn’t take long, and hopefully, they’ll be OK each time, but, should a problem arise, then treatment is available… the main thing being to, get in there early as this will often help you with your chances of making a full, and, speedy recovery. :)

© Willow Science 2015

Vicky xx

Cancer Awareness - Watch out!!!

April 14th, 2015

Lumps and bumps are a fact of life - don’t be sitting there acting like you haven’t got any - go on… check it out. I’ll give you a sec.
OK then, so what have you got… bony bits… gristly bits… the odd squidgy bit? It’s always good to know exactly, what you’ve got ‘hanging around’ - yes, make notes, draw diagrams… take photos (especially, if your memory is as rubbish as mine) - cos, if owt changes in the future, then you need to ‘get on it’ - quick - and have some sort of a reference for comparison.
Oh, throughout life, your body alters no doubt… stuff comes and goes - most of this is not too bad, but it’s the stuff that comes, stays and grows that you need to be aware of… or, things that you’ve already got, that, and for no apparent reason, suddenly looks and feels quite different… and not just women - anyone can succumb to cancer - it’s just not that fussy about whose life it invades.
So, you’ve gotta be alert, and get at this thing early… it’s no good leaving it, as, once it’s come… it’s unlikely to go all by itself - it needs a good shove - and the sooner you do this… the better. :)

© Willow Science 2015

Vicky xx

Welcome to Willow Science - BBQ safety

April 13th, 2015

Hello, I think I’m really going to enjoy this opportunity as a science writer as helping people learn all about germs and the diseases they cause is what really excites me, and, to be honest, was the main reason I chose to study microbiology in the first place. As a subject, it gives you everything - slime, fungus, and an overwhelming sense of satisfaction at being able to study and understand something that you can’t even see with the naked eye.
However, in my quest to bring diseases to you, I’ve already had to overcome much adversity; in this, my very first post, I was really pushed to the limit. You see I, like most people, love a good barbecue… and staring at pictures of perfectly cooked burgers, chicken wings, and sausages, fresh from the grill, all in the name of research… OMG - back in a mo!
Hmm, that’s better, now, where was I?
Yes, barbecues are a staple part of the long British summer - a chance to get together with family, friends, their pets, whilst also, becoming reacquainted with the ‘natural world’ after your recent winter hibernation.
However, in the ensuing chaos of dodging wasps, scraping ants from your legs, and keeping the kids out of the pond, one should never forget the importance of food safety at these occasions - remember, focus, because if you don’t, you could end up with Salmonella, or some other nasty little bug that could well cause food poisoning - which is a big deal, as its symptoms can be pretty gruesome and could end up lasting for days - with most of the ‘action’ revolving around diarrhoea, vomiting, and stomach pains which come about, usually, as a result of toxins produced by the offending microbe.
So, you want to try and avoid all of this nonsense - and where better to go for advice than to the Food Standards Agency (a bunch of folks who know all about food… and safety), where basically, what they’re saying about handling meat at a barbecue is to:

(1) Try to pre-cook all your meat in the oven - then whack it on the barbecue to give it that smoky taste you’re after. Yum!

(2) OK, so it may look charred and frazzled on the outside, but this doesn’t always mean your meat is cooked thoroughly on the inside, therefore, to make sure, simply cut into it and check that there are no pink bits, it’s piping hot, and that the juices are running clear. Remember - be a hero - if in doubt - cook it a little longer!

(3) Beware of portable barbecues - oh, not cos they’ll have your eye out or anything else dodgy like that (well, not under normal circumstances they won’t), it’s just that they take a little longer to cook your food. Be vigilant… and patient… get a good book to work through whilst you’re waiting (War and Peace should just about do it).

(4) Cross-contamination at these events can be a real problem - keep raw and cooked foods well separated, use different utensils and equipment for each, wash your hands thoroughly after touching raw meat, and especially, when you’ve been to the toilet, handled any pets, blown your nose, or, been foraging around in the bin!

(5) This one may catch you by surprise - but try and refrain from giving your raw meat a wash as it’s well known that the splashing action of water in this way can actually propel dangerous microbes all over the place from the food. But worry not; the heat of cooking will kill off any microbes present on your meat.

(6) Serve your glorious creations with utensils, and, on to plates, using cutlery that have not been in contact with any raw meat - a beautiful ‘marinated flamingo breast’ is no good if it’s served with an E. coli garnish!

And there you have it folks. OK, so I’m not saying that if you follow all these guidelines to the exact letter, then I’m sure things will go perfectly and you’ll have a day to remember for all the right reasons. It’s more like, that if you follow these guidelines you’ll reduce your chances of something going wrong as you can never completely rule out the unexpected from happening.
Yes - a random seagull flying overhead and dropping a Campylobacter-laden poop right in the middle of your meatball, pasta salad can never be entirely foreseen!

References:

Food Standards Agency (FSA). food.gov.uk (July 2014) Six tips for a top barbecue.

Murray, P.R., Rosenthal, K.S., Kobayashi, G.S., Pfaller, M.A. Ed. (2002) Medical Microbiology 4th ed. Mosby.

Prescott, L.M., Harley, J.P., Klein, D.A. Ed. (1996) Microbiology 3rd ed. Wm. C. Brown Publishers.

© Willow Science 2015

Vicky :) xx