the water weight is often too heavy for many jewel scales, because your goal is just to get the weight difference of the rock in air and in water, you do not need to put water container on the scale. You need to smartly use the jewel scale in a "spring scale" way. that is, you need to hang the rock to the scale. To do this, move water container to underneath the scale, use a metal hook to hook on the center of the scale, the hook's lower end will be right underneath the scale so that you can hang the rock on it to merge into water container (if you form the wire a heart shape, you put the scale in the heart, that's it). How to make water container go under the scale? of course, you can use your hand palm to hold the scale above the water (I use a 2"x3" x 2' long wood beam to hang out of table)
to me this looks like black magic. how does the scale register the weight if the object is suspended bo something outside the scale? does the string itself interfere with the reading?
You can use it on any nonporous item. In the case of items that float, you would have to make sure the item remained completely submerged, e.g., hold it under rather than hold it off the bottom. Use an object of negligible volume relative to the potato to hold it under, e.g., something that displaces almost no water.
@@LANDSHARKK because to lift the stone there is 2 components, him pulling the string and the water aplying pressure to the bottom of the rock. And we know that force cant just go in one direction so the neutral force from the water gets applied to the scale in turn showing the weight. Just a guess.
The rock displaces a volume of water = to its volume. Notice the volume of water in the container appears to increase, the volume of the water plus the rock. The mass of the water increases an amount equal to the volume of the rock. See this video about Archimedes, the first to express the principle of displacement. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-KMNwXUCXLdk.html
The rock displaces a volume of water = to its volume. Notice the volume of water in the container appears to increase, the volume of the water plus the rock. The mass of the water increases an amount equal to the volume of the rock. See this video about Archimedes, the first to express the principle of displacement. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-KMNwXUCXLdk.html
@DrDirtSoilVideos So doesn't the string itself effect the results? I've seen people use these types of wire cages and they make sure and tar it with the wire cage first to be more percise. Am I correct in assuming the string itself is so small that the difference in results would be almost negligible?
The suspending method is a water displacement method. In this method, the mass of the water is used to identify the volume of water displaced - more precise measurement than a graduated cylinder. However, if the object (rock or otherwise) touches the bottom of the container, the mass then is the mass of the rock plus the mass of the water, rather than the mass of the water plus the volume of water displaced by the rock.
However, particle density is not. Specific gravity is essentially the particle density divided by the density of water, resulting in a dimensionless number.
