All about the Vernier Calipers

The following video depicts a really comprehensive introduction to the vernier calipers and how to use it. Try the practice questions at the end of the video!

How to read a micrometer

The following video from YouTube is a good demonstration of the correct way to use a micrometer.

Possible New Method to define a Kilogram using the Silicon Crystal

The standard kilogram is presently being defined by a chuck of platinum-iridium alloy kept in France as you have learnt in your textbooks.But scientists have found that due to the loss and gain of atoms over the years, the alloy has changed its mass and does not have 1 kilogram in mass exactly.A new method to define a kilogram is being worked out which uses silicon crystal as the defining measure. Read all about it at http://www.nature.com/news/2007/070528/full/070528-2.html