Gas Production by Yeast

Gas Production by Yeast

The apparatus we used in the first experiment are as follows: Syringe,

fresh yeast, three solutions of glucose at concentrations of 1%, 5%

and 10%, enamel dish, boss head, small crystallising dish, glass rod,

spatula, 10cm measuring cylinder, stop clock, thermometers and a water

bath.

Prediction

I predict that as I increase the concentration of glucose, the more

bubbles will be produced.

Method

My partner and I placed one spatula of fresh yeast into a glass

beaker, 5cm3 of 1% glucose was added to the beaker slowly bit at a

time, my partner and I mixed the two together thoroughly. When the

glucose and yeast were mixed together well, we drew 5cm3 of the

mixture into a syringe we then made sure that the mixture was not near

the nozzle by pulling the plunger back as far as it could go. We both

filled a water bath with warm water at a temp of 35oC and placed the

syringe in the bath, a boss head was used to hold the syringe down.

My partner then started the stop clock and I was on hand to count the

number of bubbles produced each minute. I intended to work out an

average number of three readings. After washing the equipment out we

intended to repeat the experiment with 5% and 10% concentrations of

glucose.

Results

I could not get results out of the experiments undertaken, due to the

fact that the mixture in the syringe was leaking out. This effected

my counting of any bubbles.

Evaluation

The reason my experiment did not work that well and I could not get

reliable results was, because the syringe was placed under the water

and the boss head was placed on it, the solution was leaking and

effecting my counting of bubbles. I intend to improve my experiment by