X uses the pulley
Pulley is a simple machine consisting essentially of a wheel with a grooved rim in which a pulled rope or chain can run to change the direction of the pull and thereby lift a load.
Pulleys can be used to simply change the direction of an applied force or to provide a force/distance tradeoff in addition to a directional change.
Pulleys are clever devices that allow you to lift large weights with much smaller forces. The length of the string used to lift the pulley determines how much force is needed. For example three string lengths allow us to lift a heavy object with a force equal to 1/3rd of its weight
In the sandpit we have a pulley system which gives force and mechanical advantage. The pulley makes work seem easier because it changes the direction of motion to work with gravity. Let's say you have to lift a heavy load, like a bale of hay, up to the second floor of a barn. You could tie a rope to the bale of hay, stand on the second floor, and pull it straight up. Or you could put a pulley at the second floor, stand at the first floor, and lift the bale of hay by pulling straight down. It would be the exact amount of work in either case, but the action of pulling down feels easier because you're working with the force of gravity.
The pulley in my centre is made up of four pulleys and one length of rope that goes around in a big loop. The idea came from another centre in the area. The bucket which is used for transporting the water and the sand is attached to the rope by a big hook.
The children use the pulley for transporting mainly sand and water, from one end of the sandpit to the other by pulling on one rope. Today S demonstrated how he uses the pulley. In order for him to transfer the bucket of sand to the far end, he pulled on one side of the pulley until it got to the spot in the sandpit where he wanted to deposit the load. To return the bucket to where he was standing, he pulled on the other piece of rope. Children soon learn through problem solving how to effectively operate the pulley and that the system will not work if both pieces of rope are pulled at the same time. The Children discovered that the heavier the load the stronger the pull one has to make to keep the pulley moving. Children also learn to take turns by deciding who pulls the rope and who offloads at the other end. They engage in dialogue.
A pulley really saves effort when you have more than one pulley working together. By looping a rope around two, three, or even four pulleys, you can really cut down on the effort needed to lift something. The trade-off? Well, as you increase the number of pulleys, you also increase the distance you have to pull the rope. In other words, if you use two pulleys, it takes half the effort to lift something, but you have to pull the rope twice as far. Three pulleys will result in one-third the effort — but the distance you have to pull the rope is tripled!
I explained that the pulley system also operated the chair lifts in the mountain and for those children, who had been on chairlifts, were able to see the connection. Instead of transporting bucket loads of sand or water, the pulley operated chairlifts transport people. The chairlifts reduce the amount of time it takes a skier to move from the bottom of the hill to the top and it enables the skier to save his energy for the ride down on the slopes. The system also enables the transportation of hundreds of people all at once in a matter of minutes.
The children learn scientific terms like wheels and axles which help machines to work: they learn about the forces ,downwards and upwards ,and about gravity. 
Hi Luana
ReplyDeleteVery interesting reading. I am well informed by the pulley system now. This is a simple but great example of technology. From the stone age days I think you would find pulleys would have been put into place then. Thinking of what technology looks like then to now, we can see the massive improvement.
A thought came to mind just now of when the Egyptians were building the pyrimids in Egypt. I remember seeing a biblical movie once, and there they showed how the Tower of Babel and other like structures were built. Men used to pull these large rocks on a 'pulley system', using ropes and oil to make them go...then someone had to run in front to pull out the logs, then run to the front to lay them down for the oncoming load.....
The simple creation of a fishing rod...a pulley system too...what mechanics call a 'block and tackle' - used to haul out the engine in the car. abseiling....and many more.
Cheers
Rosie
http://rlandsberg.blogspot.com/
hey Lu,
ReplyDeleteLike Rosie said I am now very informed about the history and uses of the pulley system. This is a piece of technology that I would like to implement in my centre too. THe only recomendation that I would make here is that I only see one place where you have spoken about what you did. Would be great to hear more about how you facilitate the learning in this area.
All in all you have done a wonderful job in creating these reflective blog posts Luana. I like the fact that you have chosen two out of three areas of technology to reflect on that are not digital, I think that tamariki these days know so much about the digital world, but somewhere along the lines knowledge about non didgital technology is getting left behind.
Thanks for sharing I have thoroughly enjoyed reading and commenting on your blog.
Carly.
That sounds so much fun, Luana. I would really love to have a go on it. It reminds me of my childhood. How we used this technology to build our house in China. It was simple but effective. It saved us lots of time and strength to carry bricks and heavy things from the first floor to the second or third floors.
ReplyDeleteIt is such a fantastic activity for children to learn problem solving, turn taking, and sharing. It also provides them the opportunity of observation and cognitive development, and physical development of gross motor, upper strength development, balance, and coordination, etc. It also involved lots of cool learning about science and technology as you have mentioned.
Happy learning through your play!!!
Nina
Luana, I think that the pulley system is a simple but effective resource that is passed down by our old generation, which will definitely stimulate the children’s interest in discovery of everyday technological experience in your centre. I like the ways which the children used the pulley system to transport sand and water from one side of the sand pit to the other, as this provide lots of opportunities for them to work together, learn from each other, problem-solve and turn-take while they are playing with it. Your reflection gave me an excellent idea which I will use when working with my room’s teaching team to make one for our children. Additionally, our team members’ (Carly, Nina and Rosie) comments have awaken me that the pulley system has a strong cultural background to encourage cultural diversity for our children. That will bring a lot of fun for the children when we examine the example that people came from different parts of the world, at different times and how they utilise the pulley to help them lift large weights with much smaller forces.
ReplyDelete