Grade Levels:  7, 8

Subjects(s):  Math and Science

Learner Outcomes:

Goal of Lesson:

The students will compare the difference of an object staying afloat in fresh water compared to an object staying afloat in salt water to better understand how huge whales can float in the ocean.

Objectives:

1.  The student will learn how a whale can stay afloat in the ocean.
2.  The learner will learn the difference in density of fresh water compared to salt water.
 

Time Frame:  45 minutes

Materials:

1.  1000 ml beaker of water
2.  One raw egg per pair of students
3.  One box of table salt per group of four students

Technology Tools/Courseware:
1.  Internet capability

Teacher Notes:

Safety:  No concern for this lab activity.  Remind students of lab procedures such as no horseplay and tasting the water and the salt.

Procedures:

Preassessment:

1.  Review density
2.  Review mass and volume.
3.  Discuss the dimensions of a whale in both mass and volume.
4.  Discuss the density of salt water compared to fresh water

Exploration:

1.  Fill the beaker with 500 ml of water.
2.  Carefully add a raw egg.  Do not crack open.
3.  Observe what happens.
4.  Slowly begin to add salt and stir gently.
5.  Observe what happens.
6.  Continue to add the salt and observe the results.
7.  Record the results in the data table below.

Data:
 

Observations in fresh water	Observation in salt water	Final conclusion
1.	1.	1.
2.	2.	2.
3.	3.	3.

Modifications:

All students can successfully participate in this activity.

Enrichment Activities:

        1.  Look up the major density currents in the oceans.
        2.  Read a book on the Titanic and write a book report on how
             the Titanic could have stayed afloat longer.
        3.  Use the Internet to find out about submersibles such as the ALVIN.

4.  Research Jacques Cousteau and out about his research and development of submersibles.
5.  Research the aqualung or scuba gear.  Describe how they work and how divers use them to breathe underwater.
6.  Look up Salt Lake in Utah and find out about the density of salt in the lake.
7.  Look up the Dead Sea.  Discuss why it is called the "DEAD" sea?

see Rubric

Questions:

1.  How important is the saltwater environment to the survival of the whale both in nature and captivity?
2.  How does the concentration of salt affect the floating of the egg?
3.  Does the egg float better in fresh water or salt water?
4.  Based on your observations, where is it easier to float, in a fresh
     water lake or the ocean?
5.  What happens to a whale's internal organs when they accidentally become beached?
6.  Based on your observations, why can a large aquatic mammal such a a whale swim and float in the ocean?

Check the data table above for completion.