Try this: Imperial Pie!

The measurements in this recipe are in non-metric units. You will need to change them into metric before you can make the recipe!

What you will need:

If you don't have a food processor, you can break the biscuits with a rolling pin

Mix the ingredients for the base together. Make sure the biscuits have been broken down to crumbs

Use a clean bowl when you make the topping!

The finished pie

Download the recipe for printing

Download a conversion chart

Try this activity online

WARNING: This activity involves melted butter, hot water, electric beaters and a food processor. Younger mathematicians should ask an adult to help.

 

For the base:

• A mixing bowl
• Wooden spoon
• A food processor, or a rolling pin and a tea towel
• A springform pan, 8 inches across
• some butter to grease the pan
  
• 8 ounces of gingernut biscuits
  
• 4 ounces of butter
  
• 2/3 fluid ounces of brown sugar
  
• 1 fluid drachm of ground ginger

1. Grease the springform pan
   
2. Crush the gingernut biscuits with a food processor. If you don’t have one, wrap the biscuits in a teatowel, and crush them with a rolling pin.
   
3. Melt the butter in a microwave or on a stove
   
4. Mix all the ingredients in a bowl
   
5. Press the mixture into the pan to make a crust
   
6. Put the pan into the fridge

For the filling:

• A mixing bowl
  
• Electric beaters
  
• Wooden spoon or spatula
  
• 1/4 pint of cream
  
• 14 fluid ounce can of sweetened condensed milk
  
• The juice of two lemons, and the rind of one
  
• 3/4 pint can of evaporated milk, chilled
  
• 1 fluid drachm of vanilla essence
  
• 2 fluid drachms of gelatine dissolved in 2 fluid ounces of hot water

1. Whip cream with the beaters
   
2. Carefully mix (fold) in the condensed milk
   
3. Add the lemon juice and rind
   
4. Beat in the evaporated milk, vanilla and dissolved gelatine
   
5. Pour the filling into the base
   
6. Put the pie into the fridge and chill well

What’s happening:

When you try this activity, you might find it takes almost as long to make the conversions as it does to make the pie, and we’ve even given you a conversion sheet! Measurement is a lot easier when everyone agrees on what units to use.

In Australia, and in almost all the rest of the world, we use the metric system. But fifty years ago, Australia used a system of measures called the Imperial system. The Imperial system uses ounces and pounds to measure weights, and feet and miles to measure distances.

The Imperial system evolved over hundreds of years, with different groups of people comparing weights with each other. Because some groups tended to trade between themselves, sometimes the meanings of weights changed between groups. In 1850 in England, there were three different ounces: troy ounces for measuring precious metals, apothecary ounces for measuring chemicals, and avoirdupois ounces for measuring everything else.

Currently, there are three countries in the world that don’t use the metric system. They are Liberia, Burma, and the United States of America. The United States uses a system called American Customary, which uses avoirdupois ounces and pounds to measure weights. However, some of the larger measurements are different to Imperial. For example, a US ton is 2000 pounds and an Imperial ton is 2240 pounds. A metric tonne is 1000 kg, which is about 2205 pounds.

The main reason for using the metric system is that converting between units is easy. But the metric system also allows everyone to compare measurements without getting confused. A metre in France is the same as a metre in Australia, and the same with kilograms, and litres. But there are even some metric units that change from country to country. For example, in many countries, including New Zealand, a tablespoon is 15 mL, but in Australia it is 20 mL. Even some terms for numbers can have different meanings. A dozen usually means 12, but a baker’s dozen is 13!

More information:

English weights and measures

Conversion table for most measurements

Avoirdupois on Wikipedia (more advanced)