In a practical Science lesson discussing Energy Transfers, Work Done and Power, 11L1 were visited by Andrew Farley from Easton and Otley College. And his tractor, towing a large yellow device called a Dynamometer.
A Dynamometer can measure how much Work a tractor can do, measured both in kW and horse power. To put some context to those units, 1 horse power = 750 Watts. One LED light bulb will be about 10 Watts, whereas the tractor boasts an impressive PTO (power take-off) of up to 120hp (89.5 kW).
Although, as the students discussed on the day, the reading from the Dynamometer is never as high as the claimed PTO. The reason why is all to do with work done, power and energy transfers. All of these topics feature in the Triple Science module P1, Explaining Motion, which 11L1 have just finished studying.
The chemical energy from the fuel is used to power the tractor. Some of the chemical energy from the tractor’s fuel is transferred to the surroundings as heat, or as noise. On a day that was not quite the warmest, for once the energy transferred as heat was not a bad thing for those nearest the engine! The aim of the engine is to transfer as much energy from the chemical store of fuel, into kinetic energy, moving the tractor.
The class discussed the theory and carried out an experiment taking readings from the engine with the Dynamometer. And of course, at the end, some could not resist a sit in the front seat of the tractor! Adam Birks commented, ‘it was good to experience a practical session on this topic. It was particularly interesting for those who are keen on engineering or agriculture.’ Bobby Copping said, ‘having the tractor there gave us a better insight rather than just reading the information in a book’.
We would all very much like to thank Easton and Otley College, Andrew for his time (and his tractor!), and in particular Mr MacDonald for organising the visit.