Lab 05: Buoyancy and Archimedes’’ Principle

PHY 110A – Lab 05: Buoyancy and Archimedes’’ Principle

For this lab, we will use a buoyancy simulation at the PhET website. You can access this simulation at: http://phet.colorado.edu/sims/density-and-buoyancy/buoyancy_en.html This simulation has two tabs. We will use the “Intro” tab to become familiar with how the sim works. The we will use the “Buoyancy Playground” to experiment with various materials and fluids. Introduction Click on the “Intro” tab and complete the following steps. In the check boxes on the left, select gravity, buoyancy, mass, and force indicators. (You do not have to record results for this part.) 1. Weigh each block in the air. 2. Place each block in the water. Does it sink or float? 3. Weigh each block in the water. 4. When a block is in the water, how much water is displaced? (Subtract 100.0 L from the reading!) 5. The scales can be moved. How much does each scale weigh? Buoyancy Playground Click on the “Buoyancy Playground” tab. Make sure the volume is set to 5.00 L and the fluid density is set for water. Select the gravity, buoyancy, mass, and force indicators. Select the wood block. Complete the following steps and record your data in the table below. 1. Weigh the bock in the air. 2. Put the block in the water. Record its weight if it sinks. 3. Record the volume of fluid (water) displaced. 4. Record the buoyant force and gravity force. 5. Repeat the steps above for each of the other materials (Styrofoam, ice, brick, aluminum). 6. Repeat the steps above for all five materials with “gasoline” as the fluid, then for all five materials with “honey” as the fluid. Fluid Material Weight in Air (N) Weight in Water (N) Float or Sink (F / S) Volume Displaced (L) Buoyant Force (N) Gravity Force (N) Water Wood Water Foam Water Ice Water Brick Water Aluminum Gasoline Wood Gasoline Foam Gasoline Ice Gasoline Brick Gasoline Aluminum Honey Wood Honey Foam Honey Ice Honey Brick Honey Aluminum Questions 1. How does the buoyant force compare with the weight of the block if a block floats? 2. How does the buoyant force compare with the weight of the block if a block sinks? 3. If a block sinks, what is the relationship between the weight in air, the buoyant force, and the apparent weight in the fluid? 4. Bonus question: What is the weight of the scale?