Effects of Sugar Concentration on Carrot Mass Through Osmosis

Objective

To investigate how carrot slices change in mass when placed in distilled water and in a sugar solution, and to determine how solute concentration influences the direction of water movement.

Hypothesis

If carrot slices are placed in pure water, then they will increase in mass because water will move into the cells. If carrot slices are placed in sugar water, then they will either gain less mass or possibly lose mass because water is more likely to move out of the carrot due to the higher solute concentration outside.

Background Information

Osmosis is the net movement of water across a selectively permeable membrane from an area with a higher water potential to an area with a lower water potential.
A hypertonic environment has more solute outside the cell, causing water to exit the cell.
A hypotonic environment has less solute outside the cell, causing water to enter the cell.

In plant cells, the central vacuole holds water and solutes. Changes in water movement affect turgor pressure, mass, and physical firmness.

Materials & Methods

• Carrot slices
  
  

• 100 mL distilled water (0 g sugar)
  
  

• 100 mL sugar solution containing 10 g dissolved sugar
  
  

• Scale
  
  

• Cups or beakers
  
  

• Timer
  
  

Two sets of carrot pieces were weighed. One set was placed into plain water, and the other was placed into a sugar solution. Both solutions stayed undisturbed for 48 hours before re-measuring the mass of each sample.

Procedure Summary

1. Prepare two solutions:
   
   

   • Cup A: 100 mL of distilled water
     
     

   • Cup B: 100 mL of water with 10 g of dissolved sugar
     
     

2. Mass each carrot sample before immersion.
   
   

3. Place carrots into each cup and leave them for approximately 48 hours.
   
   

4. Remove carrot pieces, gently dry surface water, and re-measure mass.
   
   

5. Compare initial and final masses to observe water movement.

Analysis

The carrot slices placed in pure water showed a larger increase in mass (+5 g), indicating that water entered the carrot cells through osmosis. Distilled water is hypotonic relative to the carrot tissue because it contains fewer dissolved solutes than the intracellular fluid.

The sugar water environment likely had a lower water potential due to dissolved sugar. Because of this, less water moved into the carrot, resulting in only a +3 g increase. The solution was relatively hypertonic compared to distilled water, reducing how much water the carrot absorbed.

These results demonstrate that the direction and magnitude of osmosis depend directly on solute concentration differences between the carrot cells and the surrounding solution. Higher solute concentration outside the carrot reduces water gain.

Conclusion & Reflection

Our hypothesis was supported. The carrot pieces gained the most mass in distilled water because water flowed into the cells to reach equilibrium. In the sugar solution, mass still increased but to a lesser extent, suggesting a smaller water gradient.

Possible sources of error include:

• Variations in carrot slice thickness
  
  

• Incomplete drying before weighing
  
  

• Slight evaporation of water over time
  
  

For improvement, future trials could test multiple sugar concentrations (e.g., 0g, 5g, 10g, 15g) to generate a full trend curve and calculate percent change. Measuring firmness changes or conducting shorter time intervals would also show how osmosis progresses over time.

A real-world application of this experiment includes agricultural food storage—carrots and other vegetables stay crisp in hypotonic environments but lose firmness in hypertonic ones (like when salt or sugar is added).

Egg Osmosis

The purpose of the naked egg experiment was to observe how an egg reacts when placed in solutions that are hypotonic or hypertonic. After watching an instructional video, we predicted that the egg would get smaller in a hypotonic environment and increase in size in a hypertonic environment. We began by recording the egg’s starting mass and soaking it in vinegar to remove its shell.

Prerequisite Information

Osmosis

Osmosis refers to the movement of water molecules across a selectively permeable membrane from an area where water is more concentrated to an area where it is less concentrated.

Hypertonic, Hypotonic, and Isotonic Solutions

These terms describe how the concentration of dissolved substances in a solution compares to the concentration inside a cell or object placed in it.

Final Observations

Our predictions were supported by the results—the egg increased in mass in vinegar and distilled water, and decreased in mass when placed in corn syrup.

We also questioned why the egg grew even larger in distilled water than it did in vinegar. We reasoned that vinegar is not purely water, so the egg needed to absorb less water to reach balance, whereas distilled water allowed for more water movement into the egg, causing it to swell more.

Properties of Water Posters

Macromolecules Posters and Matching Notes