**1. How heavy is a gram?**

A gram is not much at all!

A teaspoon of medicine would weigh about 5 grams.

**2. Who started the metric system?**

The French introduced the metric system shortly after the French Revolution in the 1790s.

**3. How far is a metre?**

A metre was initially defined a one ten millionth of the distance from the equator to the North Pole on a line running through Paris.

**4. Which are the most commonly used prefixes?**

Kilo − 1000 times the base unit

centi- 1/100th of the basic unit

milli- 1/1000th of the base unit

**5. What is a litre?**

Think of a litre as the space occupied by a cube of side 10 cm.

**6. What is a tonne?**

A tonne is a mass of 1000 kg

**7. What is the difference between mass and weight?**

For mathematical purposes the mass and the weight are the same.