# Buoyant Force and Archimedes Principle

Buoyant Force and Archimedes Principle

## Pre-Lab Questions

1. Draw a free body diagram of a hanging mass before it is submerged in water. Make sure to label your forces.

2. Draw a free body diagram of a hanging mass after it is submerged in water. Make sure to label your forces. Which force is the force you measure with the spring scale?

3. Apply Newton’s second law to your free body diagram in Pre-Lab Question 2 to solve for the magnitude of the buoyant force.

## Experiment 1: Buoyant Force and Floating

### Data Sheet

Table 1. Number of Washers a Clay Boat Can Hold Before Sinking

 Type of Liquid Number of Washers Plain Water Salt Water

### Post-Lab Questions

1. What did you observe when you placed the ball of clay into the beaker?

2. What were characteristics of the boat design that floated the best? Explain why this works, and the clay ball fails to float using Archimedes’ Principle.

3. How much water does an object have to displace before it will float?

4. If your clay boat weighs .005 kg and is floating, what is the upward force the water is exerting on the boat?

5. How could you improve your boat design to increase the buoyant force without using more clay?

6. In the second part of the experiment, does the boat hold more weight in the regular water or the salt mixture? What does this say about the relative densities of salt water and plain water?