Biology Lab Write Up

By Savannah Mitchell

Introduction

A question arose regarding the relationship between amount of solutes in a solution and the solution's mass, and this experiment was created to find an answer to that question, or to at least answer the hypothesis that had developed over that very question. There were many variables in this experiment, such as the type of solution, which was the independent variable, and the mass of each tube used in the experiment, which was the dependent variable. There were also the constants, which were the amount of water in the tubes, and the amount of solution in the cup.

Hypothesis

If the solution contains more solutes, the mass will be lesser. If the solution contains less solutes, the mass will be greater.

Materials

  • 3 dialysis tubes
  • String
  • 1 liter of drinking water
  • 1 liter of regular soda
  • 1 liter of diet soda
  • 1 liter of purified water
  • 3 plastic cups
  • Permanent marker
  • Electronic balance (scale)

Procedure

  1. Tie one end of the three tubes with string.
  2. Add 10mL of drinking water to each of the three tubes, the tie the other ends.
  3. Add 200mL of original soda to one cup, 200mL of diet soda to another cup, and 200mL of purified water to another cup.
  4. Measure the mass of the three tubes with the balance and write them on the sides of the cups and in a data table for the experiment.
  5. Place one tube in each of the three cups.
  6. Let sit for 24 hours.
  7. Remove tubes and measure them one more.
  8. Record difference on the side of the cup below the original measurements, and in the data table.
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Conclusion

The hypothesis was, "If the solution contains more solutes, the mass will be lesser. If the solution contains less solutes, the mass will be greater." This was proven to be true by the lab results, which showed that the greater amount of solutes the solution had, the lesser the mass of the tube was after being submerged in said solution for 24 hours, or vice versa in the case of the purified water, which had less solutes than the water in the tube, causing the mass of the tube to increase. This concludes that there is a relationship between amount of solutes in a solution and osmosis.