Year 2 Science

Units of Measurement - Baking a Cake

girl baking with measurements

You know that everything is made of matter. Sometimes we need to know things about matter. We need to know how much of something there is, or how much something weighs, or how big or little something is. To find out all this, we need to take some measurements.

Measuring things is a way to use numbers to say how big or small things are, or how heavy or light, or how hot or cold. Has anyone ever measured how tall you are? Has anyone ever measured how much you weigh?

You know how important measurements are if you've ever helped somebody bake a cake. You have to measure out each ingredient carefully, use a cake tin that's a certain size and heat the oven to a certain temperature. Every step of the way, you use numbers and make measurements. Here's a recipe for chocolate cake. But something is wrong with it:

Do you see what's wrong with the recipe? Could you make this cake? Begin by measuring out 175 (175 what?) of sugar. 175 teaspoons? 175 kilograms? 175 tonnes?! The cake will taste very different, depending on how much sugar you add. Is the cake tin 18 centimetres across, or 18 metres? Centimetres and metres are both units for measuring length. Now do you bake the cake for 45 minutes, days or years? These are each units for measuring time.

Now do you see what's wrong with the recipe? Somebody forgot to write in the units of measurement. Measuring means counting, but you have to know what you're counting. To make sense, every measurement needs a number and a unit.

Now add in 'grams' by sugar, butter, cocoa powder and flour in this recipe; add 'teaspoon' next to baking powder and vanilla extract; 'centimetres' by the cake tin; '180 degrees Celsius' and '45 minutes'. Now that makes more sense. Why don't you try baking this cake?

This activity is adapted from pages 310 - 311 of What Your Year 2 Child Needs to Know, which can be purchased here. Click below to see the related activity.

history and geography owl