**Mass** is the amount of matter contained in an object and is measured in **kilograms**.

**Mass is not the same as weight**.

**Weight** is the mass of an object when acted on by a **force of gravity** and is measured in **Newtons**.

Some common objects and their approximate masses are:

**Milligram**- a speck of dust**Gram**- one sheet of A4 photocopy paper, one millilitre drop of water**Kilogram**- one litre of water, your Maths textbook**Tonne**- a small car

MASS RULES | CONVERTING MASS UNITS |

1000 milligrams = 1 gram
1000 grams = 1 kilogram 1000 kilograms = 1 tonne The metric "tonne" (rhymes with "on") is not the same as the imperial "ton" (pronounced "tun"). |
The magic mass number is 1000.
When converting from large unit to a small unit, you multiply.
When converting from a small unit to a large unit, you divide. |

**Converting from Large Units to Small Units**

**Q1.** 3 kg = g
**Q2.** 4.3 g = mg
**Q3.** 5.7 t = kg
**Q4.** 6.2 kg = g
**Q5.** 45.8 kg = mg

**Converting from Small Units to Large Units**

**Q6.** 6 kg = t
**Q7.** 9.4 g = kg
**Q8.** 5.6 mg = g
**Q9.** 18.3 g = kg
**Q10.** 5.8 g = t

**Answers:**
**Q1.** 3000
**Q2.** 4300
**Q3.** 5700
**Q4.** 6200
**Q5.** 45 800 000
**Q6.** 0.006
**Q7.** 0.0094
**Q8.** 0.0056
**Q9.** 0.183
**Q10.** 0.0000058

Currently, one ounce of gold (28.3 grams of gold) is selling for about $1600.00. What is your worth in gold?

A photon is a particle of light which has **no mass** at all. It travels about 300 000 kilometres per second in a vacuum.

Einstein's famous formula, E=mc^{2}, basically means that energy (E) and mass (m) are equivalent. If you could change all your mass to energy then you could
travel at light speed like a photon!

**Q1.** If you are a male adult, your average mass is about 80kg. If you are a female adult, your average mass is about 70kg. What is your average mass in kg?

**Q2.** Adult male bodies have about 42% muscle (flesh). Adult female bodies have about 36% muscle (flesh). How much flesh do you have on your body?

**Q3.** If you look after yourself, your muscle is prime beef. The current supermarket price for a kilogram of steak is about $20. How much does your muscle cost?

**Q4.** There are 206 bones in the human body. Adult male and female bodies have about 35% bone. What is the mass (in kg) of your skeleton?

**Q5.** Soup bones sell for about $5 per kilogram. How much does your skeleton cost?

**Q6.** What is your total cost?

*Hey, we're kidding! We know you're really priceless!*

Three penguins, Tax, Tex and Tux, all went to a new amusement park ride called the "Iceberg". There is a limit of 110 kg for the ride. All three wanted to ride together but weren't sure if it was safe.

The scale can only hold two penguins at a time so it was difficult to figure out the mass of all three penguins. (Penguins are very social and didn't want to get on the scale alone.)

Here's what they found:

- Tax and Tex together have a mass of 90 kg.
- Tax and Tux together have a mass of 68 kg.
- Tex and Tux have a combined mass of 52 kg.

Can they safely ride together?