How the Rate of Diffusion is Affected by the Temperature of Water

Essay by rebelgirl0839College, UndergraduateA+, August 2004

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I found that this experiment gives me an understanding on how osmosis and

diffusion works. In its simplicity, it explains the process that our bodies (mainly cells)

use all the time. It also showed me that even with the temperature changing, it doesn't

drastically change the rate of diffusion.


Diffusion is important in all living systems. Osmosis is the passage of water from a region of high water concentration through a semi-permeable membrane to a region of low water concentration (Purchon 1). Diffusion is the movement of a substance from an area of high concentration to low concentration (Biological 21).

With this knowledge we tried to recreate diffusion for students to understand the process. The dialysis bags represented our selectively permeable membrane with the fluid inside it, sucrose. How much of the substance moves from the cup to the bag quickly depends on the temperature of the substance.

The class used four different temperatures to measure the rate of diffusion.

I thought that the rate of diffusion would increase as temperature increased because the more heat put into the process the quicker the molecules will move.

The null hypothesis is that no matter what the temperature is the rate of diffusion will stay the same.

Materials and Methods

The materials used were a dialysis bag, string, pipet, beaker with water, 10% sucrose water, and a balance. The variables that we made standardized were the concentration of the solute, length of the dialysis bags, and time.

Each group poured 10 milliliters of 10% sucrose into two 15 cm long dialysis bags and bent the end of the bags and tied them. Then the bags were immersed in water, dried, and measured. Next the bags were put into room temperature (about 20°C), 60° C, 45°C, or ice water (0°C).