Sprung a leak?

As if someone turning on the tap isn’t enough to make you squirm - how about the idea of harvesting ones own urine to take the concept of a renewable resource to a new level? That’s right; you produce around 520 litres of the stuff each year and it contains stacks of nutrients that could be used to make fertilizer for plant crops.

Agriculture relies on mined phosphorous to make the fertilizers it uses for food crops, but this supply of phosphorous is set run out in just 50 – 100 years –eeek! Turns out that our urine contains not only phosphorous, but potassium and nitrogen as well, making it a potential number one (sorry about that) source of these minerals.

But before you get all flushed with pride at being so clever to make the stuff in the first place, producing liquid fertilizer from urine is still being trialled and tested, but its golden possibilities will surely keep it in the pipeline.

Which makes me think of a joke:

Q. Why did the fish blush?
A. Because the seaweed

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Magnif – icent droplets

Here is a good breakfasty kind of activity, so sweep aside the toast and get your goggles on.

What you will need

• Water
• Newspaper
• Plastic sandwich film
• An eye dropper

What to do

1. Place a sheet of plastic sandwich wrapper on top of the newspaper, just around 20 cm of the stuff will do nicely.
2. Drip some drops of water on top of the plastic film. Give a few drops of different sizes a go.
3. Now look closely, very closely at the newsprint through the drops.  Have a look at the shape of the drops from the side - you may have to rest your head on the table for this one, ahhh now doesn’t that feel better!

What’s happening?

Your mini magnifying glasses are spreading out the light that you see, and it’s the curved bits in the drop that’s doing it. When the light beams hit this curvy surface, they change the direction in which they are travelling - they bend, and this makes the newsprint look bigger to your eye. This whole light bending thing is helped along by the fact that water is thicker than air so when light hits the surface of the water, it hits on the brakes and slows down.

The amount of magnification will change depending on how close you look at the drop, so experiment a bit by bobbing your head up and down a bit (Polly want a cracker?).

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