Osmosis LabBy: Andy Guidas,

Christina Szabados, Sam

Bonelli

QuestionDo different types of solute affect osmosis in potatoes?

Hypothesis and Purpose

Hypothesis: If we test the rate of osmosis in solutions of glucose, sodium chloride, distilled water and sucrose, then the potato in the sodium chloride solution will loose water, while the other potatoes will gain water.

The purpose of our experiment was to determine how types of solvent can affect osmosis.

Controls and Variables

Controls: Potato size Concentration of solution Time allowed for osmosis Temperature

Variables: Type of solvent

Procedure1. Prepare solutes by dissolving 5g of solute into 50mL of water. Then stir to dissolve, and add water to the mixture up to 100mL.

2. Use the 5mm diameter specimen extractor to make 4 potato cylinders.

3. Use a scale to weigh each cylinder. Record this under Initial Mass in your data table.

4. Add one potato cylinder to each cup of solute.

5. Let sit for 30 minutes. After the time has elapsed, dry off the potato cylinders and record their Final Weight in your data table.

Collected Data:Solute (5%)

Initial Weight

Final Weight

% Change

Glucose 4.6g 4.6g 0%Sucrose 4.0g 4.1g 2.44%Sodium Chloride 3.0g 2.7g

-11.10%

Distilled H2O 4.3g 4.7g 4.25%

Pictorials

Conclusions The purpose of this lab was to

determine if the solvent affects the rate of osmosis. From our data we found that the potato in the sodium chloride solution had 11.10% less mass after 30 minutes. While in the water and sucrose the mass of the potato was greater (2.44% and 4.25%)than before.

What We Learned This data shows that there was more salt in

the 5% sodium chloride solution than in the potato because water went out of the potato.

There was an equal amount of glucose in the glucose solution and potato because there was no change in mass.

There was more sucrose in the potato than in the sucrose solution because water went into the potato.

There was a greater amount of particles in the potato that in the water because water went into the potato.

This shows that our hypothesis was for the most part correct, except that the nothing happened to the solution of glucose.

Further Conclusions

Our data shows that in sodium chloride the water went from the hypertonic solution to the hypotonic potato. While in the sucrose and water the water went from the hypotonic solution to the hypertonic potato.

Experimental Errors

It was difficult to get the potatoes to be the same size, this could have affected our results because this change in size affects surface area, which could affect the rate of osmosis.

If we did not dry off the potatoes enough this could cause the potato to be a great mass than it actually was.

Things to Change

I think it would be beneficial if we had a better way to make the potatoes the same size, like also measuring their length.

It might also be interesting to try other types of solution to see how the results differ or to try mixing different types of solutions to see if this had an affect.

Bibliography http://nutritionresearchcenter.or

g/healthnews/wp-content/uploads/2008/02/cs_mph.jpg

http://easycoffee.com.au/images/T/WhiteSugar500g.jpg

http://www.biochem.arizona.edu/classes/bioc462/462bh2008/462bhonorsprojects/462bhonors2007/gsantarelli/glucose.gif

http://www.tulpehockenwater.com/images/products/gallon_big.jpg