Stardate Friday 14th October 2005 Issue 154

If you are a teacher of Key Stage 4 Science, English or Citizenship, or know someone who is, then this is a clever new resource for you…

Developed by Highwire: Hackney City Learning Centre, and funded by the Wellcome Trust, Genetics and Citizens aims to get students to understand complicated issues from all perspectives. And what could be more complicated or have more perspectives than the current debate over genetic engineering?

Students are asked to develop characters in role-play, each with their own agendas in scenarios such as genetic testing, screening and designer babies. And an issue like GM food, cloned animals, human cloning or gene patenting can be looked at in more depth in groups.

The pilot was successful with students of all abilities and now the materials are available free of charge to interested teachers of KS4 Science, English and Citizenship, and advisors working in the field.

The materials available include lesson plans, the student websites and even video clips and these can be downloaded from the teacher resources section of the website www.highwire.org.uk. They are also available on CD ROM or DVD. Email the format you require and your address to genetics@highwire.org.uk

One of the things that Galileo was most famous for was pointing out that something’s mass does not affect how quickly it falls to the ground. Tricky to see when there is air resistance and a lack of high places that are safe to drop heavy weights from!

You will need:

• String
• Modelling clay
• Weighing scales

What to do:

What’s going on?

Pendulums don’t just swing, the weights at the end are actually falling. The pendulum motion allows them to ‘fall’ for longer than they would if we chucked them out a window! Which means we can examine how different masses are affected by gravity.

When compared to a falling hammer or feather we might expect the lighter weight to fall more slowly than the heavier one. But if you watch your pendulums you’ll see this is not the case. It doesn’t matter what the mass is, all objects fall at the same rate, as long as you rule out air resistance. It is tricky to get rid of air resistance but you can minimise the effect by making the bobs similar sizes and spherical!

If you want to see the hammer and feather experiment in a vacuum have a look at it on the Moon…

Nutritionist Simone Baroke is here again to tell about the very worst of all E numbers, the ones designed to kill!

Kill or be killed: Preservatives

Food preservation is nothing new. Salting meat, smoking fish and the use of sugar to turn strawberries into jam is what got our ancestors through the barren winter months. In the more recent past, several powerful microbial inhibitors were used to preserve foods, including borates, fluorides and phenols. Formalin, a highly toxic aqueous form of formaldehyde, was once a popular preservative added to milk. After a while it became evident that such potent concoctions weren’t just good at eradicating germs – they could knock the socks off us, too!

Preservatives need enough clout to keep salmonella, E. coli, listeria, clostridium and friends in check, while leaving our innards intact. Several suitable substances are approved by the EU, and their E-numbers are found in the 200’s range.

Sulphur dioxide and sulphites (E220-E227), can leave you with a weird aftertaste and they destroy the thiamin (vitamin B₁) in foods. Sensitivity to sulphites, especially among asthmatics, is not uncommon. Dried fruit is usually treated with sulphur dioxide. Nisin (E234) is a bit of a “special case” among preservatives. It is the only antibiotic allowed for food preservation and is made from certain strains of the Streptococcus lactis, bacteria. Nisin occurs naturally in milk and some cheeses, and because it is a protein, it’s non-toxic. To us, that is.

Despite preservatives’ appalling public image, much of our food would not be safe without them. Bacteria, yeasts and fungi instantly colonise just about any morsel of unprotected food, and if we don’t kill them, they might just kill us.

Galileo Galilei Just because Galileo was a very clever man doesn’t mean it is impossible to understand what he did! Planet Science is here to help with a great page about the man himself, aimed at a Primary audience. Find out what he had to do with clocks and telescopes and why we have to thank him for figuring out how the solar system works!

Spaced Out The Spaced Out project is a superb idea; it’s a scale model of the solar system! But if you have ever tried to explain how vast the solar system is using analogies of peas, oranges and watermelons you’ll know that you soon run out of space (and fruit). A NESTA awardee, this scale model is the size of the UK, with the Sun located at Jodrell Bank, and the planets resting in sites around the country.  Now you can find all your solar system resources on their website too. There is material for Key Stages 2, 3 and 4, all available to download, from worksheets to word searches, it will keep every pupil occupied!

That’s all for another week! Thanks for reading and contributing and if you have know of any events, jokes, or activities please let us know at planet-science.news@nesta.org.uk

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