Metric Conversions

King Henry's Story

Once upon a time in a faraway land there lived a king who loved chocolate milk. His name was King Henry.

Throughout his kingdom, King Henry made sure that all of the cows were fed great supplies of chocolate to continue to provide him with his beloved chocolate milk drink.

King Henry drank chocolate milk with his breakfast. He drank chocolate milk with his lunch. He drank chocolate milk with his dinner. He even drank chocolate milk for his bedtime snack. King Henry drank chocolate milk by the litres!

King Henry wanted all living creatures in his kingdom to enjoy chocolate milk as much as he enjoyed chocolate milk. However, a litre was not the best serving size for every creature. The Royal Carpenter was called for and the command was given for new serving vessels to be created to fit every creature in the kingdom.

For the creatures smaller than the king, the Royal Carpenter designed decilitres that were 1/10th the size of a litre, centilitres that were 1/100th the size of a litre, and millilitres that were 1/1000th the size of a litre. The millilitres were just right for the Royal Beetles and Bugs of the kingdom.

For the creatures greater than the king, the Royal Carpenter designed dekalitres that were 10 times the size of a litre, hectolitres that were 100 times the size of a litre, and kilolitres that were 1000 times the size of a litre. The kilolitres were just right for the Royal Giants of the kingdom.

The Royal Carpenter lined the vessels up in his workroom from largest to smallest to show the king. The king’s vessel was in the centre of the line, for the king was the centre of the kingdom. The vessels were arranged in the following order:

kilolitre hectolitre dekalitre litre decilitre centilitre millilitre

King Henry loved the new vessels that were designed larger and smaller than his own for all of the living creatures in his kingdom. The Royal Carpenter explained that the sizes increased and decreased from the king’s litre, the original unit of measurement, by multiples of ten. He explained how to convert between the sizes by multiplying by ten or dividing by ten.

Well, King Henry tragically died not long after that.  The cause of death was very unusual.... he died of drinking way too much chocolate milk.

From then on, all living creatures in the kingdom had no trouble remembering the order of the vessels.  They just thought to themselves:

King Henry Died Unexpectedly Drinking Chocolate Milk

kilo-  hecto-  deka-  [unit]  deci-  centi-  milli-

Since each step is ten times or one-tenth as much as the step on either side, we have:

1 kilometre = 10 hectometres = 100 dekametres = 1000 metres
                 = 10 000 decimetres = 100 000 centimetres = 1 000 000 millimetres

Alternatively, we have:

1 millilitre = 0.1 centilitres = 0.01 decilitres = 0.001 litres = 0.000 1 dekalitres
               = 0.000 01 hectolitres = 0.000 001 kilolitres

The point here is that you move from one prefix to another by moving the decimal point one place, filling in, as necessary, with zeroes. 

To move to a smaller unit (a unit with a prefix some number of places further to the right in the listing), you move the decimal place to the right that same number of places, and vice versa. 

Together with the prefix sentence ("King Henry..."), this makes conversion between the different metric sizes very simple.