Earth Science Regents Performance Test Bead Drop: “Settling it once and for all!”

1. Earth Science Regents Performance Test Bead Drop:“Settling it once and for all!”

2. Bead Drop Research Team -SUNY Oneonta • Dr. Jim Ebert, Earth Sciences Dept. • Ron Chapin • Trish Emmons • Don Zaengle • Gerald Jones • Tom Sansone

3. Student Participants • Student participants in the Station 5 research project were Secondary Education/Earth Science Students enrolled in ESCI 315: Laboratory Techniques in Earth Science in the Spring semesters of 1999 and 2000

4. Variables investigated in 1999 • Variation in bead density with temperature • Variation in fluid density with temperature • Changing time to terminal velocity with fluid height in column • Variation in fluid viscosity with temperature

5. Research in 2000 • Focus on viscosity change with temperature • Construct correction curves? • Examine other fluids with less temperature-dependent viscosity

6. Let’s drop some Beads!!

7. ESCI 315 data for Red Beads

8. ESCI 315 data - Green Beads

9. ESCI 315 data – Orange Beads

10. Settling Time –expanded scale

11. Settling Time –expanded scale

12. Range of settling timeswith temperature

13. Viscosity and settling time • Water-based solutions show significant changes in viscosity with changes in temperature • Settling time may vary by up to 50% over range of typical classroom temperatures • Vegetable oil shows very slight changes in viscosity and therefore settling time with changes in temperature

14. “Channeling”and water-based solutions • Water-based solutions displayed an unexpected “channeling” effect • A visible “channel” was observed in the fluid column • Beads entering this channel settled significantly faster than beads outside the channel • Settling times in water-based solutions may vary by up to 6 seconds at a single temperature!

15. CONCLUSIONS • Use Vegetable Oil for Station 5 • Viscosity and therefore settling time is less affected by temperature during administration of the practical • With vegetable oil, it should be possible to make up a single key for each set-up and not have different keys for different times of day/temperatures.

16. Helpful hints for Station 5 • USE VEGETABLE OIL instead of water-based solutions. Oil is less susceptible to temperature-induced changes in viscosity. Therefore there will be less “drift” in settling time. Also, “channeling” is not a problem. • Be aware that settling times in oil are faster than water-based solutions. Adjust timing marks on columns to give appropriate settling times.

17. Helpful hints for Station 5 • Use Number 7 or 8 rubber stoppers in the bottoms of columns. They give a better seal than the plastic fittings. • Place the bottom of the tube in a plastic beaker or whipped topping container to ease clean-up in the case of minor leaks.

18. Helpful hints for Station 5 • Place a film-cannister “bailer” at the bottom of the tube to retrieve beads. Holes in the cannister allow fluid to drain out. • Bent pieces of coat hanger are good for the “hook” and straightened coat hangers work well to retrieve the bailer. • Thanks to Irv Soden for this suggestion.

19. Helpful Hints for Station 5 • Plastic petri (culture) dishes work well for holding the beads at each station. • Use masking tape to anchor the dishes to the table top to minimize the chances of students spilling beads (of course, this NEVER happens!)

20. Helpful Hints for Station 5 • Glue beads onto the station directions so that there is no ambiguity over which beads the students should use for each trial. • Use plastic page protectors for the station instructions. This prevents students from writing on them, shields them from spills and preserves them for future use.

21. CLEAN UP • Hot soapy water works well for removing oil from beads, tubes and stoppers. You can even use the detergent from previous years! • Oil can be kept in the original bottles indefinitely.