Jan
30
2012
1

Where is the world’s largest working watermill?

laxey_waterwheelThe world’s largest working watermill is the Laxey Wheel, also called the Lady Isabella. It can be found on the Isle of Man. A small island which lies in the middle of the Irish Sea between Britain and Ireland. As one can see from the photograph, the wheel is huge and towers over the nearby [more…]

Dec
27
2010
3

How much water does it take to float something weighing a kilogram?

cat-basinIf you want to float a thing that weighs one kilogram in water, how much water do you need? First, of course, the thing must float in water: a piece of wood, a can of peanuts or glass of instant coffee, any closed container¬† weighing one kilogram (2.2 lb) that is larger than one liter [more…]

Written by | 6,296 views | Tags: , , , , | 3 Comments
Jul
05
2010
--

Why is water wet?

water-sand-wet-handTo understand why water is wet, we first need to know what “wet” means. Obviously, for something to be wet it must be a liquid so that you can feel it as you run your hands through it. Carbon dioxide isn’t wet. Gravel isn’t wet. But for something to be wet, it must also stick [more…]

Written by | 7,347 views | Tags: , , , | 0 Comments
Jun
16
2010
--

Can I catch Legionnaires disease from my car?

windscreen-washer-reservoirIt was noticed in 2006 that professional drivers were five times as likely to catch Legionnaire’s disease as anyone else, and the UK’s Health Protection Agency set out to find out why. They surveyed the habits of survivors of the disease, and of a control group without the disease. It turned out that those who [more…]

Written by | 7,336 views | Tags: , , , | 0 Comments
Mar
24
2010
--

How much does hot water cost?

hot-water-cascadeFew people know how much the water from their cold tap costs, and even fewer realise how much the water from their hot tap costs. The cost of cold water in the UK is around a quarter of a penny per liter, so that's our starting point. How much more does it cost to heat [more…]

Written by | 7,891 views | Tags: , , , | 0 Comments
Mar
16
2010
1

What is a meander?

river-meanderThe expression meander is used to describe something that winds around without crossing itself, be it it a creek or river, or a repeating decoration in art or architecture, or also the description of such a line in mathematics. The word dates back to classical Greece, the name then and now for a river in [more…]

Written by | 5,596 views | Tags: , , , | 1 Comment
Mar
08
2010
--

Dihydrogen monoxide: should you avoid contact with this chemical?

dihydrogen-monoxideIf you worry about radon radiation, radio waves emitted by cellphones, potential risks of cancer from the fumes of hot cooking oil, and many other things, you may cringe at reading about dihydrogen monoxide (DHMO). You can at least be reassured that dihydrogen monoxide in pure form is not carcinogenic, but you will not be [more…]

Written by | 2,541 views | Tags: , , , | 0 Comments
Mar
05
2010
7

Why is oxidane so deadly?

oxidaneIn the United Kingdom, oxidane kills over five hundred people each year; in the United States it's more than five thousand per year. The substance is so deadly because it can harm people in a variety of different ways. If liquid oxidane gets into the lungs it blocks the entry of oxygen into the blood, [more…]

Feb
16
2010
--

What could be the largest body of water in Uzbekistan?

The Aral sea with no water (photo by giladr - CC-BY)The Aral Sea should be the largest body of water in Uzbekistan, shared with Kazakhstan, but since the 1960s it has shrunk to 10-20% of its original volume, entirely due to human intervention by draining off water from the Amu Darya (the Oxus river in classical times) to irrigate cotton fields in Uzbekistan. A good [more…]

Written by | 2,518 views | Tags: , , , , | 0 Comments
Jul
22
2009
1

How much does it cost to flush the toilet?

Toilet Monster (image by Katiya Rhode-Singh's  - CC-BY)The euphemism for going to the toilet used to be “spending a penny”. This probably referred to the price paid to visit a public toilet cubicle back then. But how much do we pay for the water that we flush down the loo? People pay different amounts for their water, but I’ve arbitrarily used the [more…]

Written by | 9,269 views | Tags: , , , , , | 1 Comment

Privacy Policy | Acknowledgements