The Mass of Grass?
The Basic Idea
(I'm sorry, it will not load the photograph at this time, I will try again later.) Children measure out a 10 cm square area of a freshly cut field, then remove the grass from this area. They weigh this grass and record the weight. Children are then challenged to find the weight of all the cut grass in a given area, i.e. a section of the field, the whole field.
How to take it even further or make it more challenging
Find the weight of all the cut grass at a given football stadium. Children will be required to research the size of the pitch. Find the weight of all the cut grass in Hyde Park etc. Children can research how big the park is, answer is readily available in acres which will need to be converted into metres square. Activity could be linked to food chains. If a rabbit eats 500g of grass a day how many could survive in the field? Discuss how often grass is cut, predators etc.
If a cow eats 11 kg of grass a day how long would it take the cow to cut the grass'? A goat eats 4kg per day, how many goats to 'cut the grass' in one day? 6 hours? etc. It takes you 10 minutes to collect 2kg of grass cuttings and put them into a bag. How long will it take to collect all the grass cuttings? A gardener charges £1 per 1 kg. How much to cut the grass at Hyde Park/stadium etc?