Science Lab Report

Science Lab Report INTRODUCTION |NAME: LORRAINE |LAB PARTNER: KAREN HO | |LAB EXPERIMENT: TESTING OSMOSIS WITH A POTATO |LAB DATE: NOV. 23rd / 2012 | |CLASS: Y-11-C |PERIOD:C | OBJECTIVE The weight of the potato slices will increase, decrease, or remain the same? HYPOTHESIS There will be no net movement of water molecules into or out of the potato.

MATERIALS LIST Large potato | |Cutters (in the shape of a fish) | |3 small beakers or clear dishes | |3 glass covers | |Sucrose solution | |Salt | |Distilled water | |Paper towel | pic] PROCEDURE 1. Add 200ml of distilled water, 40ml sucrose solution and 5g salt into three beakers respectively. Record the solutions concentrations, volumes, and weights. ?Use a cutter to cut the potato to the similar size. Record the weight of pieces potato.

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?Put the three potatoes slice into each beaker. Cover the beakers with glass covers and leave them for 48 hours. ?Carefully remove the potato slices from the distilled water solution & pat it dry on a paper towel. Weight the potato slices immediately.

Record the final weight of the pieces. ?Clean up the equipment & area and return materials to their proper place.

DATA AND/OR OBSERVATIONS |Potato slices weight (Before)|Material | Distilled water |Potato slices weight (After) | | | |(Quantitative) | | |? 21g |Sucrose solution 40ml |200ml |21. 5g | |? 2g |X |200ml |23g | |? 21g |Salt 5g |200ml |20g | USE TIME: 48 hours RESULTS We can Observe that the slice placed in salt is very flexible, while the slice placed in sucrose solution is flexible, but less so. Since potatoes already have sugar, less water will diffuse out of the potato placed in sucrose solution water.

The slice placed in water will be rigid, since it will absorb water. ANALYSIS ERROR ? The glass can not cover the beakers well, so the data value that we got was too close.

?We used a big size of cylinder (500ml) to measure the sucrose solution and distilled water. |150ml water ; potato weight (before/after) 20g /24g | |150ml water ; potato weight (before/after) 20g/13. 5g | |(^ with 15g salt) |

I compared with Evan’s group, our results roughly the same. CONCLUSION The water molecules move towards higher concentrations of the solution. That means that if the water outside the cell is saltier than the water inside, water will move from the inside of the cell to the outside.

As the water left the cell it was much like letting the air out of a balloon. As more and more of the cells lost water, the slice of potato became soft and flexible. (the potato in water with sucrose solution just on the contrary. )