1. Density- Buoyancy
Goal:
To use buoyancy to determine density

2. Total Force F = mg – Fb (Fb = ρwVg)

3. W air and W water

4. Procedure
Weigh an object in the air and in the water --- totally submerged.
Wair
Ww ---- the object is suspended by a thread from the arm of a balance

5. Density = mass / volume ρ = m / V m = ρ V
Weight of an object in the air:
Wair = m g = ρ V g (1)
The weight loss is due to the Buoyant force
Wair - Ww = FB = ρw g V (2)
ρw is the density of water

6. Get the experimental value of density
Use (1) to divide (2)
Wair / (Wair – Ww) = ρ V g / ρw g V
Cancel g V
Wair / (Wair – Ww) = ρ / ρw
ρw Wair / (Wair – Ww) = ρ
ρw = 1000 kg /m^3
ρexp = 1000 x Wair / (Wair – Ww)

7. Check web to get the book value of the density
Compare and calculate the error%