floating scale 3 in 1

pinshape

The Concept: For the science challenge, I aimed to develop something that illustrates the principles of buoyancy, displacement, and density. Density is calculated by dividing mass by volume, so both need to be measured accurately. Volume is determined by measuring the displacement of water in a container, while mass is calculated using buoyancy. Furthermore, I wanted to demonstrate the comparison between two objects with different densities but identical masses, just as Archimedes did. The Design: -Measuring Volume: A cylinder is filled approximately halfway with water and the level marked. Coins are then tossed into it, causing the water to rise. The difference in height equals the volume of the coins divided by the surface area of the water. If the surface area is 1000mm^2, the water will rise 1mm for every cm^3 of coin volume. To determine this area, the radius of the cylinder must be calculated as the square root of 1000mm^2/pi = 17.84mm. -Measuring Weight: The cylinder has an outside radius of 25.23mm and a surface area of 2000mm^2, so it will sink 1mm for every 2g. This can be measured using the outer part that floats. -Comparing Density: On each side of the scale, the same amount of weight is placed, but one side has material denser than the other. The scale is then submerged in water where the less dense material displaces more water and this side of the scale rises. The Test: For testing purposes, I used 50c coins weighing 7.8g and having a density of 8.54 g/cm^3, as well as a silver coin weighing an ounce (31.1g) with a density of 10.49 g/cm^3.