wheel axle

Scientific Enlightenment:

A wheel and axle system, as the name suggests, is composed of 'wheel' and 'axle'. This system can rotate around a common axis, which is equivalent to a lever system with the axle as the pivot and the radius as the lever. Therefore, a wheel and axle can change the torque of a force, thereby achieving the purpose of changing the size of the torque. In daily life, common wheel and axle mechanical devices include a pulley, winch, stone mill, car steering wheel, wrench, hand-crank hoist, and the twist handle of a tap.

Scientific Principles:

    The essence of a wheel and axle is a continuous rotational lever. When using a wheel and axle, the lines of action of the forces applied to the wheel and the axle are usually tangent to both, thus their lever arms are the corresponding wheel radius and axle radius. Since the wheel radius is always greater than the axle radius, when the power is applied to the wheel, the wheel and axle form a lever that is both easy to use and saves distance (as shown in the first diagram below). An actual example is the bicycle pedals and the wheel (large gear). When the power is applied to the axle, the wheel and axle form a lever that is both difficult to use and saves distance (as shown in the second diagram below). Actual examples include the bicycle rear wheel and the fan blade on the wheel (small gear), and the fan blade and axle of a ceiling fan, all of which are examples of difficult-to-use wheel and axle applications. The relationship between the forces on the wheel and the axle is F1R = F2r, where F1 is the force on the wheel and F2 is the force on the axle, and R and r are the radii of the wheel and axle, respectively. Wheel and axle is a simple mechanical device that is easy to use. (The wheel radius is large, and the axle radius is small, so it is easy to save effort.)

Science Project:

1Recognize and prepare the necessary materials for the experiment.

2Install in sequence according to the instructions.

Three,Installation completed and debugging is underway.

Science Expansion:

Archimedes, a Greek mathematician and physicist from the ancient period, is considered to be the earliest inventor of a water pump. Archimedes was born around 287 BC.287The ancient city of Syracuse in Greece. At that time, Syracuse was economically flourishing and there was a strong trend of scientific research. Many people in the city had extensive studies in philosophy, geometry, etc. They enjoyed debate and considered it an opportunity to learn. Archimedes grew up in such an atmosphere and developed good habits of liking to think and like to learn. One Sunday, Archimedes and his classmates were sailing on a wooden boat on the Nile River, and the beautiful scenery on both sides made him dizzy. Suddenly, he saw a group of people carrying water in wooden barrels and asked, "Why are they carrying water?"?The riverbed is low, while the farmland is high, so the farmers have no choice but to carry water to irrigate their fields," a local classmate told him. "This is too inefficient. It's unclear how many buckets it takes to water one field." A kind of sympathy for the farmers arose in Archimedes' heart. After returning, Archimedes's eyes always flashed with the image of the farmers struggling to carry water. "Can water flow upwards?"?Archimedes began to ponder over this problem. Gradually, an idea emerged in his mind: "Make a large spiral and place it in a cylinder. In this way, when the spiral rotates, the water can be carried to a higher level along the spiral groove.?Archimedes immediately drew a sketch based on this idea. He took the sketch to the carpenter and asked him to help make a tool for pumping water. With Archimedes' guidance, the carpenter created a strange device. Archimedes took this to the river and placed one end into the water, gently rocking the handle. "Gurululu," as the water continuously poured out from the top of the device while rocking the handle. Water, indeed, flowed upward.