Data collection -- #2

31/7/13

Before we continue, we have to prove that the electricity is generated by bacteria only, thus we came up with the null hypothesis: "The LB broth does not generate electricity".

In the setup, we replaced the bacteria with LB broth, and our results are as shown:

Copper:

Fig. 19

Fig. 20

Thus this proves that our null hypothesis is true, and that the electricity generated is generated by the bacteria only.

Next, we moved on to testing out how aluminium affects the generation of electricity:

Fig. 21

Fig. 22

As can be seen from Fig. 22, using an aluminum electrode increases the amount of electricity generated by the bacteria.

Fig. 23

Fig. 24

Fig. 25

Fig. 26

As compared with copper:

Fig. 27

Fig. 28

Fig. 29

Fig. 30

Fig. 31

Fig. 32

We can see, from the data collected, that the aluminum electrodes caused the bacteria to generate more electricity than the copper ones. 

Data collection -- #1

24/7/13

After testing out the different metals and their effects on the rate of the generation of electricity with the E. coli (K-12) strain, we started collecting data.

The data for the Zinc electrodes are as shown below:

Fig. 17

Fig. 18

After looking through the data collected, we found that there was a very big fluctuation in the electricity generated (refer to fig. 17). Upon closer research, we found out that zinc was not a good conductor of electricity, thus we had to scrap the idea of having zinc as one of the test metals.

We decided to change the second metal to Aluminium as it is a good conductor of electricity, and it proved to be even better than Copper (refer to following post).

Day 5 - Trial 5

22/5/13

Proceeding, we tried out the effect different metals, namely nickel, tin, zinc and copper, had on the rate of generation of electricity. The results are as shown below:

Fig 12

 Fig 13

 Fig 14

 Fig 15

Fig 16

So far, we have discovered that copper is the best metal to use.

Day 4 - Trial 4

14/5/13

This time, we are changing the NaCl solution to Ethanoic acid to see if it speeds up the rate of reaction in generating electricity.

The first test (refer to Fig 9 and Fig 10) is with 100ml of Ethanoic acid (1M), the second test (refer to Fig 11 and Fig 9) is with 100ml of Ethanoic acid (2M)

Fig 9

Fig 10

Fig 11

We had to do 2 runs for the ethanoic acid with concentration of (2M) as the value of electricity being generated was fluctuating greatly. 

From this experiment, we can conclude that ethanoic acid does increase the speed of reaction, thus we will be replacing the 100ml of sodium chloride solution with ethanoic acid of concentration (1M).

Day 3 - Trial 3

8/5/13

In order to confirm the hypothesis that lowering the volume of NaCl solution will increase the rate and amount of electricity generated, we repeated the same experiment with 100 ml of NaCl solution.

The results are as shown below:

Fig 7

Fig 8

Therefore from Fig 7 and Fig 8, we can conclude that decreasing the volume of sodium chloride solution causes the rate of electricity generated to be increased.

Day 2 - Trial 2

10/4/13

After experimenting, we found the need to increase the rate of electricity produced by the bacteria, so we changed one factor: The Volume of Sodium Chloride solution.

Instead of pouring 200ml of NaCl solution, we used only 150ml of NaCl solution.

In Trial 2, we have obtained a significant change in results -- The rate of production was increased drastically.

Fig. 5 below shows the tabulated results:

Fig 5

As compared with Fig 4, the graph in Fig 6 has a faster, smoother increase, with less fluctuation than in the first trial:

Fig 6

Observations: With the decrease of the volume of the NaCl solution, the rate of the generation of electricity increases. 

Day 1 --- Trial 1

28/2/13
TRIAL RUN 1

Today we did our first run to test whether our setup is correct, and whether the bacteria will produce electricity. Fig 1 is a photograph of our setup.

Fig 1

Materials used: 

-Copper sheets (5cm x 5cm)

-4 insulated wires with crocodile clips

-200 OHm resistor

-Multimeter

-NaCl solution (salt water solution)

-Filter paper

Total duration: 30 mins

Fig 2: a diagram of our setup:

Fig 2

Fig 3: Table of the raw data collected:

Fig 3

Fig 4: Graph showing trend in increase of electricity over time:

Fig 4

Observations:

It was observed that between each transition of increase in electricity generated, there would be slight fluctuation between the values (e.g. when increasing from 2.7 to 2.8 millivolts). As time passed, the period of fluctuation between the values increased, taking a longer time to stabilize. 

Materials needed

Here are the materials needed for the trial run:

- 2 Beakers (250ml)
- 2 insulated copper wires (with crocodile clips) (20cm)
- 2 microcentrifuge tubes (15 ml)
- 2 copper sheets (5cm x 5cm)
- NaCl (Sodium chloride) solution
- Solid agar (3cm x 5cm x 5cm)
- Multimeter
- 1000 OHM resistor
- Filter paper
- Water
- E. coli

Introduction

Hello! :)
We're a group of students from RGS, doing a research study on generating electricity with E. coli.
We aim to add in our findings to the existing stock of knowledge, thus, using this blog as a journal to document and publish the data collected.
We will be starting the experiment soon, and at the same time, be updating this blog, documenting the process of this experiment.