1
Sink or Float Activity Notes

• Objective Provide experience in formulating and
  testing hypotheses, classifying, and analyzing
  data.

2

• AN OBJECTS DENSITY (DENSITY MASS/VOLUME)
  DETERMINES WHETHER OR NOT IT WILL FLOAT. IF AN
  OBJECTS DENSITY IS LESS THAN WATER, IT WILL
  FLOAT IN WATER IF ITS DENSITY IS GREATER THAN
  WATER, IT WILL SINK.

3

• THE SAME PRINCIPLE OF DENSITY COVERED IN THIS
  LESSON APPLIES TO OBJECTS OTHER THAN SODA
  HUMANS AND SHIPS, FOR EXAMPLE. PEOPLE WHO ARE
  VERY MUSCULAR AND HAVE A LOW PERCENTAGE OF BODY
  FAT FIND IT VERY DIFFICULT TO FLOAT, WHILE PEOPLE
  WHO HAVE A HIGHER FAT RATIO FIND IT EASIER TO
  FLOAT. THIS IS BECAUSE MUSCLE TISSUE IS DENSER
  THAN WATER, AND FAT TISSUE IS LESS DENSE THAN
  WATER.

4

• ANSWER THIS QUESTION IF METAL IS MORE DENSE THAN
  WATER, HOW CAN A HEAVY METAL SHIP FLOAT?

5

• THE HEAVY METAL SHIP CAN FLOAT BECAUSE OF THE AIR
  PRESENT INSIDE THE SHIP. AIR HAS A DENSITY LESS
  THAN WATER, SO AIR IN A SHIP DECREASES THE SHIPS
  AVERAGE DENSITY.

6

• YOU CAN INCREASE THE ABILITY OF AN OBJECT TO
  FLOAT BY MAKING THE FLUID IT FLOATS IN DENSER.
  SALT WATER IS A GOOD EXAMPLE OF A DENSE FLUID.
  PEOPLE FIND IT EASIER TO FLOAT IN SALT WATER THAN
  IN FRESH WATER BECAUSE SALT WATER IS DENSER THAN
  FRESH WATER. SIMILARLY, SHIPS RISE WHEN THEY GO
  FROM FRESH WATER TO SALT WATER.