Buoyancy
Recommended for grades 6–12.
Introduction
Buoyancy is the upward force exerted by a fluid on an object. The buoyant force on the object reduces the weight of the object. When an object is immersed in water, it pushes water aside. Over 2000 years ago, the Greek mathematician Archimedes discovered that the buoyant force is equal to the weight of the water displaced (pushed aside) by the object. Buoyancy is used to determine whether an object will sink or float. If the object weighs more than the water it displaces, it will sink; if it weighs less, it will float. Engineers use the principle of buoyancy when designing boats, submarines, and scuba equipment. In this activity, you will use a Force Sensor to determine the buoyant force and the weight of displaced water for three different objects.
Objectives
In this experiment, you will
- Use a Force Sensor and NXT to measure the weights of objects in and out of water.
- Determine the buoyant force of water on each object.
- Determine the weight of water displaced by each object.
- Compare buoyant force to weight of water displaced for each object.
- Use the results of the experiment to explain why objects sink or float.
Sensors and Equipment
This project/activity requires each of the following Vernier sensors and equipment (unless otherwise noted):
Additional Requirements
You will also need NXT Sensor Adapter and a LEGO MINDSTORMS NXT robotics system.
Download Experiment Preview
The student-version preview includes:
- Step-by-step instructions for computer-based data collection
- List of materials and equipment
The preview does not include essential teacher information, safety tips, or sample data. We strongly recommend that you purchase the book for classroom use.
Standards Correlations
No standards correlations for this experiment.
Included in the Lab Book
Vernier lab books include a CD with word-processing files of the student instructions, essential teacher information, suggested answers, sample data and graphs, and more.