mechanics experimental science bracket lever ruler popular science small experiment pulley group bracket 力学实验科学支架 杠杆尺科普小实验滑轮组支架

Lever scale and stand

Scientific Insights:

Archimedes once said, "Give me a fulcrum and I shall turn the world." In real life, no one can move the earth, but with this fulcrum, many heavy objects can be moved. Let’s see how levers save effort through the experiment below. 

Scientific Production:

1, identification of experimental equipment: small butterfly gears and shafts, weights, nuts, small weights, thin copper wire, plastic wire, balance ruler, hooks, chassis, base, large column.   

2,Install the large pillar on the base, then attach the sky and leveling gauge to the large pillar. The lever assembly is complete.   

3, hang different amounts of weights at various positions on the balance scale, observe and record the state of the lever—what patterns do you notice??

4, use three plastic ends to pass through the three holes on the small plate and attach them to the small hooks. (Fold the copper wire in half and cut it short.) Use copper wires to tie the hooks and the three plastic ends at equal distances, then hang them in the holes at both ends of the balance.ORing balance adjustment.   

5<t_XXXXX>Place small weights and scales respectively in the small slots on both sides of the balance to maintain equilibrium. Then, place weights of different weights and a varying number of scales in the corresponding slots on both sides to restore balance. Think about what principle this equilibrium indicates. In the experiment, we found</t_XXXXX>,If the weight of the small object being measured does not match the weight of the balance, the balance will tilt. If the balance is balanced, it indicates that the weight of the weights is equal to the weight of the small object being measured.

Note:During the experiment, different weights were hung at various positions on the balance.,Made under the correct guidance of the teacher.

Knowledge Expansion:

    The lever principle is also known as “the lever equilibrium condition”. For a lever to be in balance, the magnitudes of the two forces acting on it (the effort point, the fulcrum, and the resistance point) are inversely proportional to their arms. Effort × Effort Arm=Resistance × resistance arm, expressed in algebraic form asF1·l1=F2·l2.<t_XXXXXXXX> In the formula,F1Indicating powerl1Indicating the power arm,F2Indicating resistancel2Represents the resistance arm. As can be seen from the above formula.To achieve equilibrium, the effort arm must be several times the resistance arm; the effort is one fraction of the resistance.

Balance: A weighing instrument. It is formed by a fulcrum (axis) supporting the balance beam at its center, creating two arms. Each arm has a plate attached to it; one plate holds an object of known weight, while the other plate holds the object to be weighed. The pointer fixed on the beam indicates the weight of the object to be weighed when it does not move and points to the central scale mark. Balances are commonly used instruments in laboratories. A balance is a device for measuring the mass of objects. It is made based on the lever principle, with small plates at both ends of the lever. Weights are placed at one end, and the object to be weighed at the other. A pointer is installed at the center of the lever. When the two ends are balanced, the masses (weights) at both ends are equal. These principles are well-known to those who have studied physics. Modern balances are increasingly precise, sensitive, and come in various types. We know that there are ordinary balances, analytical balances, constant analysis balances, microanalysis balances, semi-microanalysis balances, and so on.

Scientific Inquiry:

1, observe carefully and think about what applications of the lever principle exist in daily life? Provide examples.

2, what is leverage

3, understanding the relationship between scales and levers. Key aspects of the experiment:

4, the conditions and laws of lever equilibrium.