Agar+Lab+Report

__**Biology lab report**__ __**Movement in & out of cells (Agar experiment)**__

**Results:** **No. of pieces of agar cubes** || **Length (cm)** || **Surface area (cm2)** || **Volume (cm3)** || **Surface area to volume ratio** || **Rate of conductivity change** || 1 || 2 ||  24 ||  8 ||  3:1 ||  0.75 || 8 ||  1 ||  48 ||  8 ||  6:1 ||  1.6 || 64 ||  0.5 ||  96 ||  8 ||  12:1 ||  2.64 ||

**Analysis/Discussion:**

The precautions we took for this experiment were that we ensured that the size of the agar was cut exactly to the given measurement and into cubes so that the surface area would not be inaccurate. Also, we held the conductivity probe and stirred with the glass rod so that the conductivity rod would not be affected by touching the beaker. From the results, we can see that the greater the ratio between the surface area to the volume, the greater the rate of conductivity change. From this, I can assume that the greater the surface area to volume ratio, the faster the rate of diffusion and thus the greater the rate of conductivity change. The results obtained from this experiment is more accurate than the experiment done in Secondary One instead of calculating the time it takes for the agar to turn fully red, we can calculate and monitor the change of agar using measurements. Also, observing the colour of the agar would be inaccurate as it would be difficult to tell the difference between the agar being partially red or fully red. From this experiment, we can observe how the digestive system of complex mammals work where the surface area of the intestines are increased in relevance to their volume in order to obtain more nutrients from food digested.

Time /s || Conductivity I/O-1(mS) || 0 || 0.35 || 10 ||  0.49 || 20 ||  1.13 || 30 ||  1.6 || 40 ||  3.23 || 50 ||  9.65 || 60 ||  2.08 || 70 ||  2.29 || 80 ||  2.46 || 90 ||  2.59 || 100 ||  6.89 || 110 ||  2.81 || 120 ||  2.95 ||