In our Science class we experimented with pullies to see what benefit they have when lifting heavy items. We used 10 litres of water which is 10kg to examine the effect that using pullies have on the weight of an item. Initially, we used a spring balance to weigh the water. 10 litres so 10 kilogrammes. Then we ran the rope up through one pulley and weighed the water by measuring the weight on the end of the rope. We found that by using one pulley we had gained a mechanical advantage. The weight on the end of rope was 8kg (approximately). Then we experimented with using a second pulley and found that the weight on the end of the rope had reduced to 5 1/2 kg. Finally, we added a third pulley to the system to see the effect and were amazed to see that the weight on the end of the rope was about 3 1/2 kg. What an amazing experiment!
