Lessons that go with a bang

15th December 2006 at 00:00
Contrary to popular belief, many experiments that used to put the WOW into science have not been banned, so bring the fizz back but assess the risks first, says James Williams

Can you remember getting pupils to spit into test tubes so their saliva breaks down starch? How about asking them to scrape some of their own cheek cells to look at under a microscope, or carry out blood tests on a sample of their own blood?

What about using a starting pistol to demonstrate the speed of sound on the school sports field or modelling a power line carrying mains voltage? If you can, you are probably in that band of middle-aged teachers who reminisce over the fun things we used to have in science before the health and safety police came in and banned it all.

Well, it may surprise you to know that all of the above are not actually banned. They can still - with appropriate risk assessments - be carried out in schools.

You can also make custard powder go off with a nice bang and demonstrate hydrogenoxygen and methaneair mix explosions, as well. However, according to a Royal Society of Chemistry report last year, some local authorities may have outlawed a few of these activities in the mistaken belief that there is a national ban.

There have been many complaints that practical work in science is now the exception rather than the rule and more than one survey cites a lack of experiments and demonstrations as contributing to the declining uptake of science post-16, with many children claiming science lessons are boring.

The new specifications, with their focus on how science works, have come in for some criticism with claims that the real science is missing and it's more about debate and discussion than engaging schoolchildren in the awe and wonder of practical work.

There is no doubt that pupils love a good explosion in chemistry, a yucky dissection in biology and some literally hair-raising times in physics, but how can you integrate this with the new approach?

The answer is simple: dig out the old practical manuals, look up some exciting practical experiments, carry out some risk assessments and weave them into your new schemes of work.

In Year 7, when you look at cells for the first time, doing a cheek cell swab is more interesting than peeling an onion. Pupils should only swab their own cheeks and all swabs and slides must be disposed of, but it's more fascinating looking at your own cells than those of an onion and less smelly.

At GCSE, if you are tackling chemistry by looking at real issues and contexts, why not look at some of the problems faced by people working in the industries where explosive dust is a real hazard - in coal mines, for example, or the places where grain is transported and stored?

Exploding custard powder in this context shows the danger to the pupil in a real way and can be integrated into teaching children about health and safety at work as well as teaching them the chemistry behind these explosions.

Relatively few things are actually banned nationally and most of the exciting science is still available to you to use to spark interest and get pupils thinking about science in a positive way. Provided, that is, that your local authority hasn't imposed its own ban James Williams is a lecturer in science education at Sussex University

Surely that's banned?

No, go ahead...

(No national bans in place, although education authorities may operate their own bans.)

Dissecting bovine eyes - permissible, as long as the animal from which the eyeballs came was six months old or younger when slaughtered

Dissecting sheep and goats' eyes - permissible, as long as the animal from which the eyeballs came was 12 months old or younger when slaughtered

Dissecting rats

Using air rifles in momentum demonstrations

Using starting pistols in speed of sound experiments

Pupils taking their own blood samples or cheek cell samples

Exploding cans of custard powder, icing sugar or similar

Bringing frog spawn from a pond into school, as long as it is from the common frog

Using a Van de Graaff generator to make a pupil's hair stand on end

*Risk assessments should be carried out before conducting all experiments That really is banned...

Using benzene Using genuine crude oil Using ozone depleters, most commonly tetrachloromethane and 1,1,1-trichloroethane

Holding a store of more than 100g of uranium salts

Making more than 100g of explosive materials

Experiments involving cruelty to vertebrates

Removing protected species from the wild

Find out more from www.rsc.org

Source: Surely That's Banned, Royal Society of Chemistry

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