IB MYP Integrated Sciences e-Assessment : Nitrogen cycle Exam Style Practice Questions - New Syllabus
Question (18 marks)
One of the most important nutrients required for plant growth is nitrogen. Nitrogen fertilizers can be added to the soil to increase plant growth. In this question, you will plan an investigation to study the effect of fertilizers. Nitrogen fertilizers are often supplied as a concentrated solution which needs to be diluted before use.
In addition to standard laboratory equipment you are provided with the following:
Design a method to investigate the effect of the concentration of fertilizer on the growth of wheat seeds. In your answer, you should include:
- your research question
- the independent, dependent and control variables
- a list of equipment you will use
- a description of the method you will use to collect sufficient data and make suitable measurements
- a statement of how you will make sure your method is safe.
▶️Answer/Explanation
Ans:
Research Question:
How does the rate of growth (as measured by height and/or biomass) of wheat seedlings over a defined interval change as the concentration of nitrogen fertilizer solution is varied?
Variables:
Independent Variable: Rate of nitrogen fertilizer solution concentration (e.g., 0%, 25%, 50%, 75%, 100% of recommended dilution).
Dependent Variable: Wheat seedling growth (as measured by: a) seedling height in cm, and/or b) seedling biomass in grams).
Control Variables:
Variety of wheat seeds (same type).
Quantity of soil per beaker/pot.
Equipment List:
Same variety wheat seeds
Same size and type beakers or pots
Same volume and type soil or hydroponic setup
Preparation of Fertilizer Solutions:
Make fertilizer solutions of 0%, 25%, 50%, 75%, and 100% strength with distilled water.
Sow an equal number of wheat seeds in the same size and type pots containing the same type and volume of soil.
Spray the respective fertilizer solutions on each pot, with distilled water for the control group.
5. Safety Precautions:
Use safety goggles and gloves when working with the fertilizer solutions.
Do this in a well-ventilated space to prevent inhalation of any fumes from the fertilizer.
Identify all solutions clearly to avoid accidental ingestion or misuse.