Concept
Archemedes' principle states that an object immersed in a fluid is buoyed up by a force equal to the weight of the fluid displaced by the object. The weight of a fluid is equal to it it's density times it's volume times gravity.
Materials
Spring scale, 500 ml beaker, 500 g mass, styrofoam cup.
Procedure
1. Fill the 500 ml beaker to the 300 ml level.
2. Measure the weight of the 500 g mass using the spring scale and record.
3. Lower the 500 g mass into the water until it is submerged, but not touching the bottom.
4. Observer and record the new water level, and observe and record the new weight of the 500 g mass.
5. Remove the 500 g mass from the water and place in the styrofoam cup. Place the cup and 500 g mass in the beaker. Record the new water level.
Analysis
1. Calculate the buoyant force of the water on the mass.
2. Calculate the volume of water displaced by the 500 g mass.
3. Calculate the weight of the displaced water. How does it compare to the buoyant force? Explain.
4. Compare the water level of the mass in the cup to the water level of the mass submerged without the cup. Which was higher? Explain.
5. Explain how a metal object could float in water.
