0%, 20%, 40%, 60 %, 80% and 100%
The remaining percentage on some of the above percentages will be made up of water, So that all the solutions have the same amount of liquid in them to ensure a fair test. I then added 2 ml of algae to each solution I made up all my solutions and labelled them clearly so they did not get mixed up and I left them for a week. When I get my results back I am going to use a counting cell to see how much algae has grown. I will use the following table to find out how much algae has grown.
Safety
To ensure safety in this experiment I will follow the following rules:
- Always wear safety Glasses
- Stand at all times
- Report any spills immediately
- Follow basic safety lab rules
- Work tidily
- Be sensible with equipment
Fair Test
To ensure I fair test I am going to try and make my measurements of the fertiliser as accurate as possible, so I can get as accurate results as possible. When I leave the results for a week I am going to leave them in a safe place, so I do not run the risk of the solutions being tamped with, which would greatly affect my results so that is why it is vital.
Equipment list
- 6 test tubes
- Bottle of fertiliser
- Bottle of algae
- Test tube rack
Results
Analysis
I have produced a graph from the table of results I retained and I have showed that my prediction was correct. My prediction was the more fertiliser in the solution the more algae will have grown and I was correct in saying this, although the 100% fertiliser solution had fewer algae in it than the 80% fertiliser. I have a possible reason for this.
The algae could grow faster when the majority of the solution is made up of fertiliser, and some water is in the solution. I did not really find any anomalous results, which showed that the investigation worked well, and I am pleased the way it went.
Evaluation
I do not think this investigation was a fair test because, when I left my test tubes for a week, I think they were tamped with, because when I got the tubes back the fertiliser 100% tube had about a quarter of the liquid missing.
Another reason for this is that the tubes might have been put next to a window and the sun could of evaporated some of the solution, and this did not really affect my results but they could of greatly.
I could of used a tool, which makes the measurements 100% correct, although I got them as accurate as possible this would have been better because they would enable my results to be more accurate.
When I counted the squares full of algae on the counting cell sometimes the cell was not full of a the solution, and it was quite hard to judge the amount of the algae is the solution, so this could have also caused it not to be a fair test.
