Question 92
Activity 3.4.1: Hot coffee. Imagine you are making hot coffee for a friend who adds a small volume of cold milk, arrives in five minutes and does not like cold coffee. Method A: pour hot coffee into a cup, leave it for five minutes, then add cold milk. Method B: pour hot coffee into a cup, add cold milk, then leave the mixture for five minutes. This is a thought experiment. Imagine you will do an experiment to compare methods A and B. Make a list of the variables you would need to keep constant to make the comparison fair.
