Procedure

1) Management of Controlled Variables

Control the growth of the plants before experiment: equal amounts of liquid and sunlight will be given to the water hyacinths

During the experiment: equal amounts of liquid and sunlight are provided to each of the water hyacinths

2) Experimental Set-up

Water hyacinths will be placed in a glass box or plastic container which provides ample sunlight but shelters the plants away from rain which may otherwise affect the results of the experiment. 200ml of liquid will be added to the beakers containing the water hyacinths in order to allow them to grow.

3) Procedure for Collection of Data

To track the growth of the plants, the length of the plants will be measured every day and any change in the colour of the plants' leaves will be recorded. The data will be presented in a form of a line graph so that any changes in the heights of the plants in the course of the experiment can be clearly seen through the graph.

4) Steps Taken to Complete Investigation

1. pH values of each type of liquids are recorded down in table form
2. 5 liquids and tap water are poured into each of the 5 containers
3. 5 water hyacinths are placed in each pot/container and be placed on the classroom windowsill.
4. 3 days later, all changes to the plant due to independent variables are to be observed and recorded down
5. Record down and tabulate all observations and data throughout the experiment.

5) Location, Environment and Time of Investigation

• Surrounding temperature of the environment should not be too high or too low/around room temperature.
• Sufficient sunlight to enter the environment and enable the plants to carry out photosynthesis.
• The investigation should lasts at least 1 to 2 weeks, so as to have enough time for the dependent variable to cause impact on the plants and hence show differences on the height of the plant before and after the investigation.
• Since we are watering the plants with different kinds of mixtures, alkaline or acids and water regularly to ensure the fairness of this experiment, the location should be in an indoor environment or somewhere that rainfalls are unable to reach.

6) Variables

Independent Variable

• Different types of liquid used to grow each plants

• In the process of the experiment
• Before the experiment has started

Dependent Variables

• Appearances of the plants after being exposed to liquids of different pH values
• In the process of the experiment
• After the experiment has ended

Controlled Variables

• Water hyacinths
• pH values of each liquids
• Type of container
• Amount of liquids and water to grow the plants

7) Precautions Taken to Minimise Human Error

• Keep the decimal points of the data recorded constant.
• Measurements and readings will be taken carefully in order to minimise human error.
• Use suitable and.appropriate statistical methods to calculate and manipulate the data. (e.g. Graph plotting / calculation of mean, median and mode of the data)
• Ensure that the environment in which the experiment set-ups are located in are exactly the same, if not similar. This is to prevent outside factors from interfering with the results of the experiment.
• Repeat the experiment several times if time permits in order to determine if the data collected from the first experiment was not a one-off happening that would not repeat itself again under the same circumstances.
• Determine the controlled, dependent and independent variables to fully understand how the data should be collected and recorded in such a way that it is clear.