Measuring the weight of an object in water involves understanding buoyancy and using a simple method based on Archimedes' principle. This principle states that the buoyant force (or the upward force) on an object submerged in a fluid is equal to the weight of the fluid displaced by the object.
Steps:
- Weigh the Object in Air:
- Use the scale to measure the object’s weight in air. Record this value as Wair (in units like grams or newtons).
- Submerge the Object in Water:
- Suspend the object in the container of water so it is fully submerged but not touching the bottom or sides. If using a spring scale, attach the object to the scale and lower it into the water. If using a digital scale, you’ll need to account for the water’s effect (see below).
- Measure the Apparent Weight in Water:
- Record the new reading on the scale while the object is submerged. This is the apparent weight, Wwater. The scale will show a lower value because of the buoyant force counteracting the object’s weight.
- Calculate the Buoyant Force (Optional):
- The difference between the weight in air and the apparent weight in water is the buoyant force:
Fbuoyant=Wair−Wwater - This buoyant force equals the weight of the water displaced by the object.
- The difference between the weight in air and the apparent weight in water is the buoyant force:
- Interpret the Result:
- The apparent weight (Wwater) is what the object “feels” like it weighs in water due to buoyancy. If you want the true weight, use Wair.
