May the fourth be with you. Yes you’ve probably heard it a thousand times already.  Still, have a heart will you? – we’re trying to be funny here. Not as funny as those bods from Spamalot though.  5,567 people smashing the world record for the number of people playing coconuts in one place?  It could only happen in Britain. They 'clip-clop'ed' their coconut shells in time to Always Look On The Bright Side Of Life.

Moving on swiftly - what do you think of walrus tagging? No it’s not the latest craze to hit the playground, it’s a serious science investigation into where walruses go in the summer. Here’s a clue.  It’s not Ibiza.

The line-up this week

1. Stump the Scientist: is it or isn’t it?
2. Activity of the Week: Make a compass
3. Mouses at the Ready for Periodic Placemats
4. Noticeboard: FYI
5. Recommended websites of the week
6. The Winners’ Enclosure
7. Joke of the Week

Walrus tagging is all very well if you want to keep an eye on where your walrus is heading for the summer.  But if you simply want to keep a wayward walrus on track then just give him a compass.  What do you mean you haven’t got one?  Good job we’ve put in this activity then, isn’t it? (Buffs fingernails on lapel).

Compasses are essential pieces of equipment for anyone trying to find their way around our planet, whether on the surface or deep underwater. If you buy one from a shop it will cost you a few pounds, at least, but you can make your own for next to nothing, as long as you have a magnet handy.

You will need:

• One sewing needle
• A small bar magnet. A fridge magnet may even work if you’re stuck
• One small round piece of cork (A salami-style slice off a wine cork is ideal)
• One small glass or bowl with water in to float the compass on at the end

What to do:

1. Find the North end of the magnet, if you can. Run this end of the magnet over the eye end of the needle sixty times – each time rubbing it away from the sharp end. If you don’t know which way North is, don’t worry, just choose one end and use that.
2. Now stick the needle through the piece of cork. If you’re using a slice of a wine cork, stick the needle through the circular part from one rounded edge to the opposite. Perfect!
3. Place your compass in the water, and make sure there are no metal or other magnets nearby. The sharp end of the needle should swing around to point to magnetic North.
4. (If you didn’t know which end of your magnet was which, you have a 50% chance that you have magnetised your needle so that the eye end points North. You could use a map to check this.)

What’s going on?

The Earth’s magnetic field may be weak, but it’s strong enough to exert a force on magnetic objects within it. The needle became magnetised when you rubbed the bar magnet over it – the eye end became a south pole and the pointed end became a north pole.

Putting the needle in the water allows it to move freely and orientate itself towards magnetic north. Check it out with a ‘real’, i.e. paid, for compass.

If you’re super-cool, you can use a piece of paper to float the needle on instead of using the cork. Put the paper onto the water surface first, then place the needle on top.

If you are extra super-cool you could use rice-paper to float your needle on. After the rice-paper has become soggy and sunk to the bottom, the needle will float on its own, supported only by surface tension…

This experiment came from Planet Science’s Little Book of Experiments.

And if you absolutely MUST know more about walrus tagging then check out the story here.

Do you know your arsenic from your erbium? If not, then you need to spend a little more time perusing your periodic table and what better place to do it than AT the table. Those nice folks at RGB Research have given us ten to give away! They are high quality 10" x 20" place mats, laminated on both sides and sealed around the edges.

Hang on.  Is that a brand new element, never before seen by man? No it’s a bit of sausage you fool!

If you want to win one then send an email with your name and address, and the words PERIODICALLY in the subject line, to planet-science.news@nesta.org.uk.

The draw will take place at 5pm on Wednesday 9th May.

It’s all about movies this week isn’t it? So how about a peek at Hollywood Science.

This blockbuster of a site from the Open University explores the science behind some of our favourite movies.  Could Paul Newman really have eaten all those eggs in Cool Hand Luke?

Talking of Hollywood superstars… Wallace and Gromit would love the British Cheese Board website (that’s Cheese Board not cheeseboard – slaver at the thought of a nice slab of Wensleydale). All you ever wanted to know about British cheeses. And probably all you didn’t want to know too.  Why is Stinking Bishop so smelly anyhow?

The British Cheese Board has produced a series of Education Packs for Key Stage 2 which all use British cheese as an underlying theme. There’s also a new resource called All About Cheese, which is aimed at Foundation Teachers and Key Stage 1.