Sink or Swim

1. “Sink or Swim?” By Sarah Rushing 2/26/2010

4. Background information Mass is a measure of weight, but density is a measure of compactness of a substance. So a measure of gold can be equal to a measure of feathers, but the density is much greater in the measure of gold. This fact was discovered by Archimedes as a way to prove that the king was being tricked by a craftsman making his crown. He could prove this by the displacement of water because gold is more dense than silver it will weigh the same and displace less water. Archimedes also noticed that he felt lighter when in water. This feeling relates to buoyancy, because when something is less dense than water, in this case, it will float. So why is it that a steel ship can float on water? A ship has a lot of space that is filled with air and the total density is less than the density of water. When the ship is broken and takes on water the total density increases and becomes more than the density of water and the ship sinks. http://www.visionlearning.com/library/module_viewer.php?mid=37

5. Sink or Swim– Part 1 In the plastic box, you will find 8 objects. You may take these objects out to observe them. Record the characteristics you find on the following table. Be sure to use all features of the items when you are noting their characteristics. Note: The BOLDFACED words from this slide forward are from various Bloom's Taxonomy categories.

6. List as many characteristics that you can think of to classify the objects in the plastic box.

7. Sink or Swim – Part 2 Think about whether or not the objects will float or sink in water. Now sort your objects using the characteristics from before and your predictions of whether the objects will float or sink in water. Record your predictions in the Sink or Swim data table.

8. Sink or Swim Data Table

9. Sink or Swim – Part 3 Write a procedure for testing each object. Number your steps and be sure to include recording of data and preparation of the testing tank. Remember to be specific think about the amount of water, if it should remain the same, how the object will enter the water, and how you will define floating. Perform a dry run to decide if your procedure needs to be modified before beginning the experiment.

10. Sink or Swim – Part 3 _____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

11. Sink or Swim – Part 4 Use your procedure to test each object. Collect your data on the following table and take notes to help you remember what happens draw pictures on the next page of what happens with each object. Remember to include your predictions from the earlier table.

12. Sink or Swim Data Table – Part 4

13. Sink or Swim Data Table – Part 4 Continued Item Number Picture Item Number Picture

14. Sink or Swim – Part 5 Decide if any of your objects needs to be retested. If you decide to retest any item be sure to make note on the table about both tests. If you need more room for writing feel free to use the back of the handout.

15. Assessment 1.) When observing the paper clip it sank in water because A. it is heavy. B. it is dense. C. it is light. 2.) When observing the piece of wood it sank in water because A. it is dense. B. it is buoyant. C. it is light.