Experiment: Demonstrating diffusion through a semi-permeable membrane
Directions: Answer the questions in the hypothesis and conclusion sections on a separate piece of paper.

I Purpose: To demonstrate diffusion through a semi-permeable membrane.

II Hypotheses:

A What do you hypothesize will happen to your vegetable in hypotonic solution?  Why?

B What do you hypothesize will happen to your vegetable in hypertonic solution?  Why?

III Materials:

2 pieces of celery stalk, salt, 2 beakers, triple beam balance

IV Procedure:

A. Hypotonic solution

-First, weigh one piece of celery on the triple beam
i balance.
-Place that piece in a beaker of pure water for ten minutes.
-At the end of ten minutes remove the piece of celery from the beaker and gentle dry the excess water from the outside.
-Weigh the piece of celery again and record the results.  If the difference in weight is negligible place the celery in the beaker again for ten minutes.

B. Hypertonic solution

-Prepare a salt solution by mixing a small amount of salt into a second beaker of water.  Add only a small amount of salt at a time until no more can be dissolved and a small amount remains on the bottom of the beaker.
-Repeat the steps above usin
g a beaker of salt water.
 
 

V Observations and Data

A. Hypotonic solution

Original weight of celery: _________g

Final weight of celery after ______minutes: _________g

What effect did the hypotonic solution have on the celery?  Did it change in appearance?  Did it feel different?
 
 
 
 

B. Hypertonic solution

Original weight of celery: _________g

Final weight of celery after ______minutes: _________g

What effect did the hypertonic solution have on the celery?  Did it change in appearance?  Did it feel different?
 
 
 
 
 
 

VI Conclusion

What happens to cells in hypotonic and hypertonic solutions?  Why?
 
 


Copyright Alexplorer. Some items taken from or adapted from other materials. This page is free for use in a classroom setting.
Back to the Biology index