An introduction to the measurement of large objects such as a blue whale. The length of a blue whale - 30 metres - is equivalent to a class of children or three buses. Whales eat krill. Each mouthful is 40,000 litres. A blue whale is equivalent in weight to 25 elephants and weighs 170,000 kilograms.
Students could apply a similar problem with diagrams of a bridge and a number of different vehicles which theoretically would need to pass under the bridge. Students could measure the height of the vehicles using a ruler and work out whether they will pass safely under the bridge. Students could convert their measurements into metres where 1cm = 1 metre.