BIO156 Carrot experiment !!!

BIO 156 Human Biology

Spring 2012

Jaclynn Greer

Carrot Water/Salt Water

Experiment

Hypothesis: I believe that the carrot in plain water will stay firm, the string will stay tight and there will be no real change in the general appearance. The carrot in the salt water may shrink/shrivel, the string will become loose and possibly fall off the carrot.

Experiment:  I cut 1 carrot into equal parts. Filled 2 glasses with water, added 1 teaspoon of regular table salt to one of the glasses of water.

The measurements prior to:

Salt water carrot- 2” x3/4”

Plain water carrot- 2” x1/2”

After measurements were made I tied pink needle point string tightly around one end of both carrots. Then paced carrots in both water solutions, for 24hrs.

Results: At the 24hr mark I did not see much change in either carrot. I decided to allow a few more hours. I am not sure but I do believe it may be from my tap water, we have a water softener in line at our home. I had not previously thought of this. I added 3hrs more .

Salt water carrot: When I returned to take a look at the carrots I was surprised to see the salt water carrot appeared to be floating in the solution. I poured the solution off of the carrot. I was not too surprised to feel the texture difference. It felt rubbery and a bit smaller to the touch. When I measured it the carrot it was 1/4” shorter in length and 1/4” slimmer. The string did not fall off but it was a bit looser.

Straight water carrot: This carrot did not seem to be floating. I poured the water off of the carrot.  There was a definite difference here also. This carrot was much firmer than the first, the string was much more taunt and the carrot looked fresh. I then measured this carrot, it measured ¼” longer and ¼” wider.

Conclusion: The carrot in salt solution  changed. I believe this was caused because salt water is a hypertonic solution. Being hypertonic the solution  caused the water in the cell of the carrot to be “drawn” out by a process called osmosis.  Osmosis is the transfer of water out of cells through a semipermeable membrane of the cell. Pushing the fluid into the higher solute solution.

The straight water carrot changed also. This was due to the solution that has been in. This solution was hypotonic. Being a hypotonic solution allowed for the cells to absorb the water and actually “swell” the cells. This is because water is a lower  osmotic pressure than the saltwater solution. It allows for fluids/water to flow into the cells.

Further note: While jotting down my notes I also observed that the carrot from the salt solution dried must faster than the water solution carrot. The start               

I enjoyed this experiment. It gave a visual for me and allowed me to touch and feel what happens in a cell osmosis cycle.

 The wait !!!                The end !!!

End measurements: Saltwater carrot 1 3/4″ x 1/2″

Tap water carrot 2 1/2″x3/4″

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One Comment (+add yours?)

  1. Rhonni
    Feb 27, 2012 @ 01:09:42

    Very interesting

    Reply

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