How to make a double scale

Double scale

The scale with two scales, known as the double balance, has been used since ancient times to measure different weights, and it was invented between the years (1602-1675) by the French mathematician Gilles Person de Roberval, who began to compare the balance with the principle of the simple lever, so that the balance bar is the main element Which determines its balance, and there is a fulcrum that adjusts the balance more accurately as well and ensures the stability of the simple arm. On the other hand, modern weighing devices have developed, and their shapes, types, and method of work differ, but this scale is still known and used by some people and in school and scientific applications. It can be made in simple home ways, some of which will be mentioned in the following article below.

Methods of working scale with two scales

There are many different methods that can be used to make a double scale with two scales, including the following:

How to make a scale with plastic cups

This educational tool is simple and very useful for children to teach them the basic principles and laws of physics based on balancing the masses and weights of different elements, and it is made in an easy and fun manual way by following the following steps:

• materials needed:
  • hole punch.
  • Two paper or plastic cups of the same size and weight.
  • Slightly thick sturdy yarn.
  • A metal, wooden, or plastic clothes hanger with serrated sides.
  • a pair of scissors.
  • Various simple blocks or toys to weigh after you're done.
  • Decoration items and stickers (optional).
• Manufacturing Method:
  • Holes are made in the selected paper or plastic cups so that each of them pierces two holes for each side, noting the need to make the holes close to the edge of the cups and opposite from the right and left.
  • Two threads of equal length are cut, each 30 cm long. It is preferable to use thick and strong threads to obtain a solid balance, in addition to placing them on one level and checking that their lengths are equal. To get two equal weights later.
  • The first thread is tied from both sides of the cup by inserting it through the holes so that an arc is made like a handle ending with two knots each in the two side holes of the cup, and the same steps are repeated to make a handle in the second cup in the same way and with the same size.
  • Threaded hanger with side slit and top hook is used; To hang the handles of the cups that were made in the previous step on them, and to obtain two balanced sides of the cups, and in the absence of a slit on either side of the hook of the hanger, strings can be used to tie the handles at the top of the paper cups to the bottom of the wire of the clothes hanger to secure it and ensure that it does not fall.
  • The cups are hung on both sides of the clothes hanger in the holes, and the scale is lifted from the hanger hook to check it and check its balance, as the two cups must be hanging at the same level.
  • Scale cups are decorated with stamps and stickers as desired, and crayons can be used to draw on them or write names.
  • The scale hangs on the doorknob; Because it is low enough for children to reach it, and the rod on which the clothes hanger is attached can be used.
  • Simple things are hung on the scale to be weighed, and it is advised not to use very heavy things and place them inside the cups, including: small rocks, pieces of light fruits, such as strawberries, berries, grapes, small toys, etc., as the heavier cup will go down and cause the scale to tilt towards it.

How to make a compact disc scale

The two scales are manufactured using compact discs, following the following steps:

• materials needed:
  • Plastic ruler.
  • Two compact discs (CD).
  • Two small pieces of plywood.
  • Long end screws.
  • mounting nut.
  • A drill for making holes in the discs.
  • Two wire steel wires for fishing with hanging hooks at the end.
• Manufacturing Method:
  • Drill two large holes in either side of the plastic ruler that will be the beam of the balance, and then make two smaller holes near the first two; To hang the two cuffs with them, then make a hole in the middle of the ruler.
  • The CDs are perforated by making 3 holes at equal distances in both discs to attach the wires to them, and to form two hanging scales for the balance.
  • Steel fishing wires with loop ends are attached to the holes on the CDs using a paperclip.
  • The steel wires attached to the CDs are attached to the ends of the ruler by hanging and tying them using paper clips.
  • A piece of plywood is divided in the middle by drawing a straight line with a pencil, then other transverse lines are made from the bottom edge towards the top, and their number does not matter, but they must be separated by a fixed distance of approximately 0.6 cm, as these lines and distance will be used as a reference point to be measured and through which an anchor point is determined. The scales.
  • The ruler is fixed from the hole in the middle of the wooden plank divided in the previous step, by securing it with a long nail through the hole in the middle of it, in addition to making a mark at the center line.
  • A nut is placed in the screw fixed to the plank of wood from the back to fix the scale and adjust it to be balanced when checking it and testing the balance of its two feet well.
  • The screw through which the balance of the scale is fixed is attached to the nut from the back by adhesive glue to ensure the stability and durability of the scale.
  • The calibration of the scale is tested, and the masses are measured and weighed through it, by selecting masses for simple elements or tools and placing them on the two scales (compact discs) and observing the result, as the scale that weights is for the heavier mass.

How to make a simple scale using an eraser and ruler

The projects of the two scales with simple components that are available in the classrooms are used as a practical application on the processes of measuring weight and distinguishing between heavier and lighter masses. in the following way:

• A small square eraser is used as a fulcrum; Because it is elastic and firm.
• A ruler is placed over the eraser so that it acts as a beam to determine the weight on which the blocks to be weighed will be placed.
• Objects to be weighed are placed, where two stones can be placed with different but relatively small weights, or known blocks, and watch the cuff on the side that will go down affected by the weight of the body above it.