Diffusion & Osmosis: Teacher’s Guide
Kit # 3674-04
Part 3B – Procedure: guided inquiry Notes
1. Make potato cores with a borer or use pre-made potato bores. 2. Weigh each core and measure the length of each core. Record your data in your laboratory notebook. 3. Place one or more potato cores in each of the mystery sucrose solutions. 4. Record your observations. 5. Wait 30 minutes. 6. After 30 minutes, re-weigh the cores, and calculate the changes in their weight. Record your data in your laboratory notebook.
Part 3B – assessment 1. Which color mystery solution had the highest concentration of sucrose? How do you know this?
The blue mystery solution had the highest concentration of sucrose, since the core weighed the least at the end of the 30 minutes.
2. Knowing that the mystery solutions were sucrose at concentrations of 0.2 M, 0.4 M, 0.6 M, 0.8 M , and 1.0 assume 0.3 M, calculate the water potential of the 0% potato core. Show your calculations and explain your 0 0.2 0.4 0.6 0.8 reasoning.
1.0
See graph above. Assuming 0.3 M, water potential = 1 bar + (–7.3 bars) = –8.3 bars
3. If you looked at your potato cores under the microscope, describe what you think you would see.
©2012, Ward’s Natural Science All Rights Reserved, Printed in the U.S.A.
Expanded cells in 100% water; shrunken cells in the blue dyed, sucrose solutions.
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