Welcome to the global experiment 2013 by the Royal Society of Chemistry.
In the short video, you'll be shown how to take part
by testing the levels of vitamin C in different fruits and vegetables.
We've been careful to design the experiment so you can take part at home or in schools,
as it uses non-specialised equipment.
Once you've completed the experiment,
you could enter your data on to our website,
to compare with students around the world, and see the global picture.
So the equipment you'll be needing to take part in a global experiment
is the fruits or vegetables to be tested,
balance or kitchen scales,
a grater, a chopping board and a knife,
a 100 cm3 measure,
a small vitamin C tablet,
ideally an effervescent one of about 1000 milligrams but as long as it's a known weight,
a measuring jug up to one litre,
a small measure, something like a 5 ml measuring syringe, or perhaps a teaspoon,
a clear plastic disposable cup,
corn flour, which is your starch solution,
some warm water, perhaps from a kettle or a hot tap,
tinctures of iodine,
and pipettes or an eyedropper.
So we have just completed the calibration step.
This took 32 drops to get the colour change we require.
You'll be repeating that twice more to get an average,
and then we'll show you the calculations.
So this is the calculation graphic for calibrating your solution.
You will be able to calculate the mass of vitamin C per drop of iodine.
You can also get this calculation from the instructions document on the website.
So now we're ready to do the experiment testing the vitamin C in different fruits and vegetables.
You'll also need to choose your experiment.
There are four choices to the global experiment 2013.
You can compare between different types of foods,
you can test for the levels of vitamin C based on where the foods were grown,
you can study the effects of aging the foods,
or you can look at the effects of cooking.
So that took four drops to get the colour change we require.
You'll now need to repeat that twice more to average your data,
and then we'll go over to the calculation.
And finally,
this is the calculation graphic for the mass of vitamin C in milligrams per gram of food.
This is the number you'll need enter into our website.
You can pause the video if you need to go through the calculations slowly.
You can find us online by searching global experiment 2013.
Don't forget to upload your results onto our global map,
to compare your data against students around the world.
So now you've seen how it's done,
it's over to you to take part.