EDU 553

CS 456

CS 423

CS 441

EDCI 560

Topic: Buoyancy

Student Sheet

Objectives:

1. Define Buoyancy
2. Measure Buoyant force

  Concept:

It is common knowledge that objects are lighter in water than in air. When an object is fully or partially immersed in a fluid it experiences an apparent loss in weight. In this experiment you will investigate buoyancy.

Materials

1.  Measuring Cylinder
2. String
3. Spring balances 
4. Clear container  
5. Water
6. Rocks

Instructions

Work with one partner only.

Lab 1

Step1:

Use the spring balance provided to measure the weight of the rock provided in air and record the weight.  Weight in Air = ________________ N

Step2:

Pour some water in the measuring cylinder provided, about 2/3 way full, and record its volume.    Volume of water = ______________ CC

Completely immerse the rock provided in the water in the cylinder. Now read off its weight and record it. Also record the new water level.

Weight of Object in water = __________________ N

New volume of water = ____________________ CC

Question :What do you notice about its weight?    Answer:_________________________________   

Q: What difference in weight do you observe?

 Answer:______________________________________

Q: What do you think is responsible for this apparent weight loss?

Answer:____________________________________________________________________

  Lab 2 - Factors affecting Buoyancy

Carefully drop the object provided in the big bowl of water. 

What happened?

Answer:_________________________________________

Now pick up the object and place it in the aluminum bowl provided and place it in the bowl of water.

Now, what happened?

Answer:__________________________________________

Why do you think this happened?

Answer:_________________________________________________

Teacher Description

Application:

The concept of buoyancy can be used to find the volume of an irregular object:

1. Weigh the irregular object provided  in air using a triple beam balance. Record your reading.

Mass in air = __________________g

2. Weigh it in water by lowering the object into water until completely submerged. Record your reading.

Mass in water = ___________________________g

The apparent loss in mass = _________________g                                 

Q: Knowing that the density of water is 1g/cc, and using your knowledge of Archimedes principle,  what is the volume of the irregular object?

A:_____________CC