Disinfectant investigation

I want to investigate...
How different disinfectant concentrations can affect the growth and reproduction of micro-organisms.

Variables

Independent variable:
I will be changing the concentration, I will be doing this by changing the amount of water added to the same amount of disinfectant

I will use full strength dettol

Other variables:
The variable I will be measuring is how much bacteria grows,
Make sure I have the same size disk so the dettol is the same

Dependent variable:
I will be measuring the size of the clear zone around the disk I will do this my measure the radius of the dettol disk

Hypothesis:
I predict that with the correct ratio of water and disinfectant it will kill more of the bacteria

The things that could change:
We need to grow the bacteria at the same temperature.

We need to grow the bacteria on the same medium.

We need the bacteria to grow the same length of time.

Reliability:
To insure reliability I will repeat the experiment three times

Equipment
Dettol
Vived
Filter paper
Water
Celitape
Petry dish
Hole punch
Bacterial solution
Twessers

Method:
1. I'm going to get the equipment

2. Punch out four disks of filter paper equal size with the hole punch

3. Pour the solution in the petry dish using a dropper and swirl it around to make sure its covered

4. Tip out the excess solution from the Petry dish

5. Mark out the Petry dish using the Vived into quadrants and label each quarter on the bottom of the 

Petry dish

6. Add all water onto the Petry dish

7. Add full strength dettol

8. Make up the solution with 400ml of water and one cap full of dettol and add that to one quarter of 

the Petry dish this is the manufacturers recommendation

9. Add more water onto the solution to dilute it and add that to the last quarter of the Petry dish

10. Write your name on the side and seal the dish with celitape

11. Incubate the dish upside down at 20°C for 24 hrs

12. Observe the petry dish and measure the diameter of the clear zone around each disk with a ruler.

13. Repeat the experiment two more times to have three results

Results:

Discussion:
bacteria is a unicellular microorganisms which have cell walls but lack a nucleus, including some which can cause disease,  bacteria is made up of DNA which is the genetic information for the bacteria, Cytoplasm which is jelly that fills up the cell and this is where chemical reactions happen here, ribosomes where proteins are made, cell membrane which controls what enters and exits the cell, cell wall and the purpose of this is to keep the structure of the cell and protect the cell contents, capsule that protects the bacteria, plasmid which is DNA of non essential processes, Flagellum and an Flagellum is a tail to help the bacteria move around, and lastly Phili which are sensing organs that can attach to other cells. Bacteria reproduces by replicating the DNA and the cell elongates and then the cells begin to divide and 2 daughter cells are produced. For nutrition the bacteria use a pump to suck nutrients in like a sponge with water 

Dettol is a disinfectant that contains chloroxylenol and what it does is it knocks down the bacteria cell wall and kills it  and is a common houshold item because of how useful and effective it is to kill bacteria 

Conclusion:
I conclude that the more dettol was added to the concentration the more bigger the clear zone got and more bacteria died

Evaluation:
The experiment went very well we got the results we needed to make a finial conclusion I can say these results were reliable because I have 3 of them that say around the same thing, next time I could try different water types like distilled

Implication:
you could impliment this by if someone gets hurt dettol gets put on wounds to kill the bacteria to stop infection
Osmosis