Steel is an alloy of iron containing other elements to improve its physical properties. Mild steel is iron with about 0.25% carbon added; stainless steel is iron with chromium and nickel added to reduce rusting. Iron will rust whenever it comes into contact with both water and oxygen. If you can stop one of those […]
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Archive | February, 2011
Gloves Gorn…
February 25, 2011 
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As I headed out to ski this morning I discovered that my gloves were missing. I searched high and low. They were definitely gone. Nobody had seen them. I could remember taking them off at a bar in the mountains the previous day and I convinced myself that I had left them there. That would have […]
Read moreSolubility…
February 25, 2011 2 Comments
[Another repost...] A solution is a mixture between a solvent and a solute. The solvent is the liquid in which something dissolves and the solute is the substance dissolved in the solvent. In salt solution, water is the solvent and salt is the solute. Things can be encouraged to dissolve in water by stirring the […]
Read moreTrophic levels…
February 24, 2011 7 Comments
[This is a repost of an older article] Yesterday I mentioned that plants are the first step in nearly all food chains. A food chain or food web describes the flow of energy between the organisms in a habitat. Each step in the food chain represents a different ‘trophic level’ (trophic is a word that refers […]
Read moreMysterious Yellow Orb…
February 24, 2011 9 Comments
Yesterday dawned bright and cold. The overcast skies were now blue and dominated by a large yellow object that appeared to be a source of both light and heat. A little research and I discovered it is called the Sun and it is the ultimate source of all Earth’s energy. Even more amazingly, every star […]
Read moreSlip Sliding Away…
February 23, 2011 3 Comments
JC asked why ice is slippery and this simple question turns out to be rather more tricky than expected. The simple answer is that the slipperiness comes from a thin layer of liquid water molecules on the surface of the ice. Ice as a solid has a crystalline structure with very little movement possible between […]
Read moreFeel The Burn…
February 22, 2011 15 Comments
I skied yesterday for the first time in five years. It was lovely but I must admit to a certain amount of discomfort. By lunchtime yesterday some of the muscles in my legs were burning, and this morning there is a dull ache in my calves. Skiing is an exercise in co-ordination and balance. The […]
Read moreLocal Knowledge…
February 21, 2011 5 Comments
There was not much snow in evidence from my balcony yesterday. Since I don’t ski very well I thought this was probably a good thing. The locals all seemed very confident that it was going to snow but I have little confidence in weather forecasts. It started to snow at about 8pm and it is still […]
Read moreSmall Blue Dot…
February 14, 2011 11 Comments
Look at the picture above. Do you see the small blue dot in the band of pale brown to the right? Do you know what that is? Go on guess! I will give you a clue. This photograph was taken by a NASA spaceship called Voyager sometime between February the 14th and June the 6th […]
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