### Did you know that ...

... hummingbird's heartbeat can reach over 2000 beats per minute? more

## Difference between mass and weight

*There is a big difference between mass and weight .*

The weight of a body is the force whereupon it attracts the Earth and it depends on the mass of himself. A body that doubles the mass of another one, also weights the double. It can be measured in Newtons (n) and in kg-force, dynes, free-force, ounce-force,…

The kg is therefore a mass unit, not of weight. Nevertheless, many equipments used to measure weights (scales, for example), have their graduated scales in kg instead of kg-force. This usually does not represent, normally, any problem since 1 kg-force is the weight in the Earth surface of an object of 1 kg of mass. Therefore, a person of 60 kg of mass weighs in the Earth surface 60 kg-Force. Nevertheless, the same person in the Moon would weight just 10 kg-force, although its mass would continue being of 60 kg.

Then, the mass is not just like the weight, it measures the attraction that exerts the Earth on a certain mass.

Posted by Turrente (Translated by Curious)