Cellular Transpiration Lab

Ashleigh Sage

Lab Report

Introduction


The experiment took place in a classroom and took about 25 hours to comlete; one hour for preparation and 24 hous for incubation. The purpose of this experiment was to test osmolarity of the water molecules in three different substances. The independant variable tested were the solutions. The dependant variable was the mass of the dialysis tubes and the control variables were the amount of water in the tubes, the size of the cups, the amount of solution, and the type of tube.

Hypothesis

If the solution has a higher percentage of solutes than the tube, then more water will escape. If the solution has less solute percantage than the tube, then water will enter the tube.

Materials

  • three dialysis tubes
  • three cups
  • funnel
  • graduated cylinder
  • 200 mL of each solution (three)
  • balance
  • string
  • drinking water (20 mL per tube)

Procedure

  1. gather materials
  2. tie one end of the dialysis tube
  3. place funnel at the opposite end of the tube
  4. pour 20 mL of drinking water into the tube
  5. repeat step 2 on other end of the dialysis tube
  6. repeat steps 2-5 on the other three dialysis tubes
  7. measure and record the mass of each tube into a data table
  8. pour 200 mL of a solution into a separate cup (one solution per cup)
  9. place a dialysis tube into each solution
  10. wait 24 hours, then remove and mass each dialysis tube
  11. record your data and create a conclusion
  12. share your data

Data

Distilled Water

before: 14.9 g

after: 14.1 g

difference: -.8 g

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Regular Soda

before: 18.8 g

after: 13.8 g

difference: -5.0 g

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Diet Soda

before: 17.4 g

after: 15.4 g

difference: -2.0 g

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Conclusion

Due to human error, this experiment was not executed correctly. The strings were not tied tight enough to avoid a lot of water from escaping. However, it was noticed that with the distilled water, less of the drinking water escaped the tube than the two soda variales. Therefore, the hypothesis was correct in regards to the amount of water that escaped.