the scaffolding process example: ap bio essay on osmosis & diffusion 1992 - question # 1 what...
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The Scaffolding ProcessThe Scaffolding Process
Example: AP Bio Essay on Osmosis &
Diffusion1992 - Question # 1
What do students need to know to get to this point?
What labs in earlier grades would lay the foundation for answering this question?
AP Bio Osmosis & AP Bio Osmosis & Diffussion LabDiffussion Lab
Initial Contents Presence of Starch Presenceof Glucose
Initial Final Initial Final
Bag
Beaker
Which molecules have moved where & WHY
Part 1Part 1
Bag Contents Temperature
InitialMass
Final Mass Percent Change inMass
Distilled Water
0.2 M Sucrose
0.4 M Sucrose
0.6 M Sucrose
0.8 M Sucrose
1.0 M Sucrose
AP Bio Osmosis & AP Bio Osmosis & Diffussion LabDiffussion Lab
At what molarity is dynamic equalibriumreached?
Part 2Part 2
Bag Contents Initial Mass Final Mass Percent Change inMass
Distilled Water
0.2 M Sucrose
0.4 M Sucrose
0.6 M Sucrose
0.8 M Sucrose
1.0 M Sucrose
Part 3Part 3
AP Bio Osmosis & AP Bio Osmosis & Diffussion LabDiffussion Lab
• What is the osmotic potential of the sucrose solution?• What is the potato’s
molarity?• Explain your results using
the concept of free energy
= - I C R T
where I = the ionization constant (for sucrose this is 1 because sucrose does not ionize in water);C = osmotic molar concentrationR = pressure constant T = temperature K
Graph the results with a “best-fit” line
The Scaffolding ProcessThe Scaffolding Process
2. Read the California Science Standard for Investigation and Experimentation:
“Science as a Process.” What would labs look like in earlier
grades that would lay the foundation for proficiency?
Science relies on reproducible observations Hypotheses provide models to explain
observations Hypotheses are created w/creativity & insight Differences between observed & expected
observations detect flaws in hypotheses Data that agree with predictions DO NOT PROVE a
hypothesis: they only fail to disprove it.
Students should explore & comprehend:
California Standard:California Standard:Science as a ProcessScience as a Process
• Grow & measure plants; measure daily temp
• Become skilled with basic lab equipment
• Design simple experiments, collect data, collaborate & analyze results
• Measure masses and volume of substances
• Make data tables and graphs, including “best fit” lines
• Use graphs to interpolate & predict
Foundation Level Examples
California Standard:California Standard:Science as a ProcessScience as a Process
• Generate data by measuring pressure vs. volume of a gas
• Calculate spring constant of an inertial balance from relationship between its period as mass
• Measure O2 consumption by animals at different
temps vs. DO2 at different levels of a lake
Intermediate Level Examples
California Standard:California Standard:Science as a ProcessScience as a Process
• Generate data by measuring Cl2 content of seawater via
titration of AgNO3
• Find the total charge in a capacitor by integrating current passed through as a function of time
• Determine the action spectrum of photosyn or % transmittance from pooled class data
• Analyze human pop growth vs. time for the past century
Advanced Level Examples
California Standard:California Standard:Science as a ProcessScience as a Process