To demonstrate how simple lever tool can be used and the Law of the lever.
A box or cylinder can be used filled with weight like a penny or other items. It can demonstrate the three different classes of levers. During the design and contraction process, the use of basic 3D geometry has been used.
How I Designed This
To create the lever, which consists of three parts, the addition and subtraction of the basic geometric shapes has been used. The lever is formed by a box. The weight are design by a box and cylinder and formed by a cutaway cylinder and box to hollow out the weight to let the student fill with different weighted items like penny, water, ect,.. The student can design different sizes of the weights and shorten or lengthen the lever. All parts are designed for 3D printing
Project: Lever System
Students will be able to test and use in practice how lever work with fulcrum, motion, resistance and effort. Students will find out how to change the fulcrum and how much effort to lift the load or balance out the load.
Wikipedia - Lever
Weight of Coins
The may also work with inventing their own design of the lever, in order to meet the principle, while being as simple and compact as possible.
The function of the lever tool is usually part of the curriculum of the secondary school or students learning about engineering and math.
The preparation for this project is the study of the fundamental mathematical principles.
Material: You also need items like penny’s, or other things that has weight. May require a scale to measure the weight of the items to put in the box or cylinder. The penny weight for a copper penny is 2.500 grams. You will need a 3D printer. No tools required.
Students first create the M1 & M2 box or cylinder, fulcrum & plank.
Adding penny to M1 & M2 and adjusting the 3D object along the plank “lever” and calculate the force and levers. A lever is a beam connected to ground by a hinge, or pivot, called a fulcrum. The ideal lever does not dissipate or store energy, which means there is no friction in the hinge or bending in the beam. In this case, the power into the lever equals the power out, and the ratio of output to input force is given by the ratio of the distances from the fulcrum to the points of application of these forces. This is known as the law of the lever.
T1 = F1a, T2 = F2b
where F1 is the input force to the lever and F2 is the output force. The distances a and b are the perpendicular distances between the forces and the fulcrum.
Since the moments of torque must be balanced,
T1 = T2. So, F1a = F2b
The mechanical advantage of the lever is the ratio of output force to input force,
MA = F2/F1 = a/b
This relationship shows that the mechanical advantage can be computed from ratio of the distances from the fulcrum to where the input and output forces are applied to the lever, assuming no losses due to friction, flexibility or wear.
Fulcrum in the middle: the effort is applied on one side of the fulcrum and the resistance (or load) on the other side, for example, a seesaw, a crowbar or a pair of scissors. Mechanical advantage may be greater or less than 1.
Resistance (or load) in the middle: the effort is applied on one side of the resistance and the fulcrum is located on the other side, for example, a wheelbarrow, a nutcracker, a bottle opener or the brake pedal of a car. Mechanical advantage is always greater than 1.
Effort in the middle: the resistance (or load) is on one side of the effort and the fulcrum is located on the other side, for example, a pair of tweezers or the human mandible. Mechanical advantage is always less than 1.
The students of lower grades can construct various weights, blocks and cylinders layout for this project. Students of higher grades can design their own lever and 3D objects to measure the different classes of levers. Learn about the classes of levers.