How to make a scale

Here it is. The purpose and requirement of making scales is to understand the structure and calibration principle of scales and to be able to make scales by hand. Instruments and equipment: plastic small disc, string, thin straight wooden rod (diameter about 10 mm, smooth surface) and nut about 0. 1 kg. Experimental method 1. Punch three equidistant holes on the edge of a small plastic plate, and tie three equal-length strings on the holes to form a weighing plate. 2. Tie the nut with a string as a scale. 3. Tie the ruler to one end of the ruler beam, and make a button with a string at a distance of about 1cm from the ruler hole. 4. Calibration: First find the star point (commonly known as "fixed disk star"), do not put any heavy objects in the disk, lift the knob of the scale, and move the scale hammer to a proper position to balance the steel scale. At this point, the position of the scale hammer is the star point, which is the starting point of calibration. Then put a standard weight of 1 kg in the plate and move the weighing hammer to balance the weighing beam. Write down the position of the scale on the scale and mark the scale. Divide the fixed star point and scale into 10 equal parts. 5. Weigh several standards with your steelyard, see how big the actual error is, and analyze the reasons for the error. Precautions 1. The balance beam should be smooth. If it is not smooth, you can apply a little talcum powder. 2. If you can't find a suitable straight wooden pole, you can use chopsticks instead and smooth the four corners. See Resources to find out why the scales of steelyard are unified. Figure 1.27- 1 is a schematic diagram of a steelyard. Point O is the lifting button (fulcrum), point C is the fixed point of the star, point G is the total weight of the weighing beam and hook, the center of gravity is B, and the weight of the hammer is G 1. The steelyard is made according to the balance of objects with fixed rotating shafts. When the weight is not hung, the hammer is at the fixed star point. When a weight Gx is hung, the hammer moves to the position X far away from the fixed star point, and the steelyard is just balanced. From the moment balance, it can be seen from Formula (3) that when the weight of the hammer G 1 and the position of the lifting button are determined, k is a constant, so when weighing an object, the distance x from the hammer to the fixed star point is proportional to the weight Gx of the object, so the steelyard is a problem 1. What factors are related to the weighing range of the scale? 2. Study and manufacture a steelyard with two handles, one of which weighs 1kg and the other weighs 2.5kg, and consider how to choose the position, weight and handle of the balance beam.