If I undertook a street survey and asked passers-by how much they weighed or how tall they were, the answers I would get back would be dependent on what system of weight and measures a person was brought up on and was familiar with. Grandparents would most likely answer in imperial units (pounds, feet & inches), and their grandchildren would reply in metric units (kilograms and metres), the reason for this is that South Africa converted to the metric system in the early 1970’s.