1.  DRIFTING DOWNWARD Plankton in the ocean

2. LEARNING OBJECTIVES Students will describe the characteristics of plankton. Students will develop abilities necessary to do scientific inquiry.

3. WHY PLANKTON MUST AVOID SINKING  Phytoplankton need sunlight for photosynthesis, so they must stay within the photic zone.  Zooplankton depend on phytoplankton and other zooplankton for food.

4. MATERIALS  Aluminum foil 10cm x 10cm square  Clear plastic containers, gallon size  1 large clear container

5. T HE C HALLENGE  Using one piece of foil design a shape that will sink slowly. The design must sink in order to be considered for competition and the slowest sinker is the winner.The model must sink within 90 seconds. Any designs that are still floating after 90 seconds will be disqualified.

6. T ESTING  1 large clear container  Test and redesign

7.  Increasing surface area or decreasing density.  Small plankton have a larger surface area to volume ratio than do larger organisms.  Flattened bodies and appendages, spines, and other body projections add surface area without increasing density.  Some diatoms form chains.  Oil or fat helps increase buoyancy  Water currents HOW PLANKTON AVOID SINKING

8. E XTENSIONS Density difference: salt Temperature: thermometer Soap: surface tension What other variables can affect the rate of sinking?

9. Family night events  DRIFTING DOWNWARD