Question

Earlier, people used parts of the body to measure length. Why is this not a accurate way of making measurements?

Answer 1

Earlier people used parts of body like hand length , foot to measure the length . However , this is not an accurate way of measurement as the dimensions of the body parts depends upon person to person .

There is a huge variation in population when it comes to size . So , what may be a unit of hand for one may not be the same for others .

Therefore the scale system came into play that has unique value . For example : in each country 1 m = 100 cm and this value is fixed unlike the size of body parts .

Sometimes , Units are also different for different countries . For example : Some countries weigh things in pounds . Therefore , international units called SI units are made that are valid and understood in each country .