Agar Experiment Report

Group member

Andrew Kiza

Umar Ali

Lamar fetu

Malachi Bell

Research Question

How can temperature affect the rate of diffusion of a solution in agar cells?

Rationale

Diffusion is one of the very important processes by which substances such as nutrients, water, oxygen, and cellular wasted are transported between living cells and their environment. This activity will help you explore the relationship between diffusion and cell size by experimenting with model cells. The rate of diffusion is measured by considering the time taken for changes to physical change occur. In this consider agar mixed with an indicator that changes colour when placed in the basic solution. It will measure the amount of diffusion that shows in the agar blocks to determine of cell size on the cells ability to obtain substances by diffusion. In this experiment, we used agar cubes to which the indicator sodium hydroxide has been added. Sodium hydroxide is an acid/base indicator that turns pink in the presence of a base such as NaOH. Thus, the surface of the agar cubes will turn pink immediately when put into a NaOH solution. The NaOH will continue to diffuse through the cube and gradually turn the inside of the cube pink.

Hypothesis

Is if the temperature is increased then the rate of diffusion will follow due to the added energy to the agar molecules. It is justified by the added energy to molecules due to the increased temperature.

Methodology

Original Experiment

In the original experiment was to check the rate of diffusion in agar at normal room. The 3x3x3cm cube of agar placed in a 200ml beaker containing sodium hydroxide. After 5 minutes of letting the agar sit in the beaker, we realised it and sliced it in half, we then measured how much of the sodium hydroxide diffused into agar.

Modification

To make this experiment more effective, we invested; by added a hot elevated temperature more effective, a thermometer to obtain temperature information much more effectiveness and more beaker to have all same temperature before heated to certain temperature much easier.

Materials

Ruler

Timer

Agar

Large beaker

Hot plate

1.0 M Noah X2

Spoon

Tongs

Sodium hydroxide

Thermometer

Methods for New Experiment

With a knife, slice a cube of agar measuring 3x3x3cm. Be sure to cut as accurately as possible.

Pour 200 mL of 0.1M sodium hydroxide solution into the beaker.

Measure the temperature of 0.1M sodium hydroxide to find the room temperature

Place the beaker filed with 0.1M sodium hydroxide onto the hot plate/heater/stove.

Take the beaker off once the temperature has reached 40 degrees Celsius (104 degrees Fahrenheit)

Place the cube of agar in the 250mL beaker filled with 0.1M sodium hydroxide and wait 5 minutes.

Once five minutes has passed, take the block of agar out of the beaker and place on a plate.

Cut the piece of agar in half and measure the amount of diffusion took place in the agar.

Record results and redo the experiment 3 additional times to see if your results are precise.

How to Calculate

Calculating % diffusion in each cube:

Calculate total volume of each cube (volume = L x W X H)

Calculate volume that did not turn pink. (That is, calculate total volume of the small portion of the cube that did not turn pink – use the same formula L X W x H)

Calculate volume diffused = total volume – volume not pink.

Calculâtes % diffusion = Volume diffuse /total volume x 100

Calculate the surface area of each cube and the surface area to volume ratio:

Calculate the surface area of a cube = L x W x # of sides

Calculate surface area/volume ratio

Risks Management

Potential risks How to minimise risks

Room Temperature Results

Cubes Temperature Diffusion(mm)

1 28 4.0

2 34 4.5

3 40 4.7

Cubes

Size Total Cube

Volume (cm3) Total Volume that was not pink (cm3) Volume of diffused cube- total volume that was not pink Percentage Diffusion

Surface area of cube cm2

Surface area to volume ratio

3x3x3cm

27cm3

17.57cm 27-17.57 =9.43cm

34.9% 9cm2 9.27

1.3

3x3x3cm

27cm3 16.58cm 27-16.58 = 10.42cm 38.59% 9cm2 9.27

1.3

3x3x3cm 27cm3 16.16cm 27-16.19 = 10.81 40.05% 9cm2 9.27

1.3

In this experiment, the data that was collected supports the experience (if the temperature is increased then the rate of diffusion will follow due to the added energy to the agar molecules). The data collected in the table and the graph indicates that’s temperature effects the rate of diffusion. The results are coherent and there’s not any outliers to distort the data in any way

Conclusion

In this experiment, the hypothesis (if the Is if the temperature is increased then the rate of diffusion will follow due to the added energy to the agar molecules. It is justified by the added energy to molecules due to the increased temperature.

The experiment was carried The hypothesis stated earlier had been accepted through this experiment. Through the analysis and my calculation that indicates the more the surface area a cell has, the more efficient diffusion is going to be. The 3x3x3 cube is to represent the b

Bibliography

Science extension experiment booklet – Semester 1

http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa_pre_2011/cells/cells3.shtml