Activity 1.2.1

Why Ships Float

Materials (for each group of 3/4 students):

• 600-ml beaker or wide mouth glass jar
• lightweight 8-in.plastic test tube
• sand
• wood splint (popsicle stick marked in 1 cm intervals) which fits inside the test tube
• metric ruler

Activity 1.2.1 Student Worksheet


Procedure:

1. Fill beaker or jar 3/4 to top with fresh tap water.
   
2. Place wood splint inside the test tube so the markings show.
   
3. Add a little sand to the test tube.
   
4. Set the test tube in the water and adjust sand until the test tube floats upright.
   
5. Look through the beaker and the test tube to see where the beaker water comes on the wood splint ruler inside the test tube. Record the water level.

Water level: ______________

1. Remove the test tube and set it aside for later use.
   
2. Begin adding salt to the water, stirring for several minutes until a little salt remains at the bottom of the beaker, creating a saturated solution .
   
3. Float the test tube again and look through the beaker, observe and record where the beaker water comes on the ruler inside the test tube.
   
   Water level: ______________
   
4. Why or why not?
   
   
5. What other variable could you change that might affect the water level? With your teacher's permission (and time permitting), investigate this variable. Report the results of your investigation on the back of this worksheet.

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