Magnificence of Ice

     Have you ever wondered how ice skaters roll ?? something to do with the ice being slippery perhaps ?!
Suprisely, it's not simple as you might think and the exact mechanism behind how ice skaters actually work has been wholly disputed for years ..

- One theory is the heat generated by the friction of skaters moving on the ice, This sound logical but it doesn't explain why skaters still slippery even at stand still !

- Anothor theory is the pressure of the skaters wight applied through the narrow metal plates that reduces the melting point of the ice and again produces a slippery film to ride on.
and it is true, pressure can reduce the melting point of ice as this experiment will demonstrate :

* Bring block of ice around which a wire is surrounding and is attached to some wights.
* Watch and wait .. The wire will start to cut in the ice block
* As the wire passes through, the ice above it will refreze !! and the block will still very very solid.
Unfortunately, this pressure theory doesn't provide the hole answer either. A typical skater only produces enough pressure to reduce the ice melting point by few degrees which would make skating at any thing just below zero a bit tricky.

So, what's the answer ??
Well, the latest scientific thinking is that there is a combination of the pressure theory and friction theory along with the fact that the bonds that bond the ice molecules together are weaker near the surface .
All together produce a slippery film needed for ice skating ;) ;)

Secrets of Toothpaste

     The average people would brush their teeth over 40.000 times in their life. Using a staggering 80 litres of toothpaste, and is such a routine part of our every day lives. Toothpaste is a fascinating stuff !

Tooth care aids have been around thousands of years. The world's oldest surviving formula is Egyptian, and it was made from Mint flowers, salt and pepper. It last for the 5th century A.D and by old comments it worked very well, although it did have the nasty side effects of making gums bleed.

Having fact that is was far less hazards than some 20th century brands ! (( In the second world war, German scientists from the nuclear industry developed radioactive toothpaste with Thorium for their domestic home market !! ))

Thorium wasn't a great idea, but other additions were much more successful. In 1901 a dentist in Colorado noticed that locals had far fewer cavities than was the others. The reason was eventually a high natural amounts of Fluoride in the water. From this basic observation, Fluoride became the dental wonder additive of choice.

So, what goes into modern toothpaste and how does it work ??

Well, the number one ingredient is something abrasive, something to scrap your pearly whites ;). For this , toothpaste manufacturing use baking soda or even silica - refined type of sand -, they also add whiteners, flavoring,something to make it foam, something to bind it all together and finally fluoride .

Now, did you know that you can make your own toothpaste out of simple household ingredients ??!!!

For this recipe, all you need to do is mixing 3 tablespoon of baking soda with one tablespoon of salt, then add 3 teaspoons of glycerin and mix them all together with a dash of water, finally add 1 teaspoon of peppermint and mix.

Try it ,, it works ;) ;)