Have you been using the camcorder this holiday?  You know.  The usual stuff like Auntie Vera walking down the prom at Cromer “Cooooeee! Come and have an ice cream, it’s delicious!”.  But are you a frustrated film director-to-be? Would you rather be filming something a little more meaty? (mind you, you can’t get meatier than Auntie Ve).  Have a look at the new Scicast site for inspiration. There’s a great one called ‘Grow Your Own Body Parts’.  Submit a short film in the competition and you could win a great prize.

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Body balance - coin pick up

A challenging activity that will test out your balancing skills as you try to pick up a coin from the ground.

You will need:

• Yourself
• A friend who is a similar height
• Two small items to pick up off the ground (a coin, cork, or grape)

What to do:

1. Stand back to back with your friend in an open area free of obstacles. Make sure your heels are touching your friend's.
2. Both people should now place the coin about 30 cm in front of their own feet.
3. Now here's the challenge, at the same time, you both have to lean forward and pick up the coin. Remember, you can't move your feet!

What's happening?

Could you do it? What went wrong? If you attempted this challenge correctly you probably found that you and your friend went flying forward when you started to lean forward. Don't feel too bad though, no-one can do it!

The reason is that everyone has a balance point – an imaginary spot in your belly that is the centre of your body's mass. This simply means exactly half of your body's mass is above (or to the left) your balance point, and half of your mass is below (or to the right) your balance point.

To keep your balance and not fall over, your balance point always has to be directly above your feet, or your base. When your balance point moves past the edge of your feet, you might look a bit silly as you fall tumbling to the ground.

When you lean forward to pick something up, you have to stick your bottom out to keep your balance point above your feet. The reason it is impossible to complete this challenge is when you and your friend lean forward, your backsides collide and you both get propelled forward!

Keeping your balance is really important in everything we do. If you couldn't balance yourself, you wouldn't be able to stand up, walk around, or ride a bike! There are a few tricky ways you can improve your balance and therefore become more stable. Test and see how stable you are when you stand on only one foot. Now, try standing with your feet wide apart and move your body really low, like a sumo wrestler.

You should find when both your feet are on the ground and your balance point is low, that you are more stable. When your feet are wide apart, you have increased the size of your base. To fall over in this position, your balance point has to move much further to get past your feet than if you were standing on one foot. You'll also notice you are more stable left to right, which is the same direction your base size has increased by in sumo stance.

But people aren't the only things where balance and stability are crucial, massive skyscrapers, statues, mailboxes, animals or even your water bottle all rely on balance. You wouldn't really want any of these things to be unstable or fall over. The Eiffel Tower and Egyptian pyramids are all good examples of big based, stable things.

This activity came from CSIRO’s Science by Email.

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