IB Biology SL IA Ideas

The IB Biology SL Internal Assessment (IA) is a project that requires students to complete an independent research project on a chosen theme. The IA is worth 20% of the final assessment and is an opportunity for students to showcase their understanding of the subject. Here are some carefully curated IB Biology SL IA topic ideas to help students get started. These ideas have been tried and tested and are popular with examiners. The list includes the basic reasons for investigating each topic, possible independent and dependent variables, and the experimental setup. It’s important to consider if the topics can be applied to one’s own life, as this shows personal engagement.

1. How do different sodium chloride concentrations affect seed germination in the bougainvillaea plant?

Experimental setup:
Soak the bougainvillaea seeds in sodium chloride of varying concentrations for a specific time period. Place them in Petri dishes and count the number of seeds that germinate. Conduct at least 5 trials, excluding control.

Independent Variable:
Sodium chloride concentrations

Dependent Variable:
Seed germination percentage

2. How does extract of the seeds and the leaves of the moringa plant (herbal medicine) show antifungal activity against the Malassezia yeast (Pittosporum) fungi?

Experimental setup:
Mix yeast and herbal medicine. Then use agar plates and fungus to test their effectiveness by seeing how many fungi grow in the different plates.

Independent Variable:
Seeds and the leaves of the moringa plant

Dependent Variable:
Antifungal activity

3. How does the concentration of zinc chloride affect the growth of plaque?

Experimental setup:
Mix different concentrations of zinc chloride in different agar plates and bacteria, and check for plaque formation over time.

Independent Variable:
Concentration of zinc chloride

Dependent Variable:
Growth of plaque

4. How effective are synthetic antibacterial products compared to natural antibacterial products against the growth of Cut bacterium acne?

Experimental setup:
Chose a synthetic and natural antibacterial product and mix them with a little water to create diluted solutions of them. Then use agar plates and bacteria to test their effectiveness by seeing how many bacteria grow in the different plates.

Independent Variable:
Types of antibacterial products (Natural vs synthetic)

Dependent Variable:
Growth of Cut bacterium acne

5. How do the different teas, used to water Vignata radiata seeds, affect the germination rate?

Experimental setup:
Place Viganata radiata seeds into various Petri dishes of the same number. Water them regularly using a diluted solution of different types of teas. Count the number of seeds that germinate over time and take note. Repeat the same procedure 5 times, including control.

Independent Variable:
The different types of teas (green tea, chamomile, etc)

Dependent Variable:
The rate of germination of Vignata radiata

6. How do varying salinity levels affect the rate of germination in the grass species Spartina anglica and Eragrostis plana?

Experimental setup:
Use different concentrations of salinity levels in petri dishes with the two different grass species and compare the rate of gemination over a period of time. Repeat for five trials.

Independent Variable:
Salinity levels

Dependent Variable:
Germination rate

7. What is the effect of potassium ion concentration (ppm) on the initial (day 0 to day 2) rate of growth of Hygrophilla difformis through mass change per day (g/day) over a period of 1 week?

Experimental setup:
Use various concentrations of potassium in the soil in which the Hygrophilla difformis has been planted to asses rate of growth over 1 week. Compare the different pots containing varied concentrations to conclude on the optimum level.

Independent Variable:
Potassium concentration

Dependent Variable:
Rate of growth

8. Effect of different concentrations of fertilisers on growth of Solanum lycopersicum?

Experimental setup:
In various pots (at least 5) containing Solanum lycopersicum, add varied levels of fertiliser concentration and assess rate of growth over a period of time.

Independent Variable:
Fertilizer concentration

Dependent Variable:
Rate of growth

9. Effects of the addition of different concentrations of 11% humic acid and 5% fulvic acid on rate of growth and fruit development in Solanum lycopersicum L?

Experimental setup:
Take the required number of pots, and add humic and fluvic acid to Solanum Lycopersicum in soil of varying concentrations and asses the rate of growth over and fruit development over a fixed period of time. Compare the different pots containing varied concentrations to conclude on the optimum combination.

Independent Variable:
Mixture of humic and fulvic acid

Dependent Variable:
Rate of change of the height of the plant

10. To what extent does light intensity affect the concentration of sucrose within a kiwi?

Experimental setup:
Exposing samples of kiwi concentrate to different light intensities for certain periods of time and measuring their sucrose concentrations before and after.

Independent Variable:
Light Intensity

Dependent Variable:
Sucrose Concentration

10. To what extent does light intensity affect the concentration of sucrose within a kiwi?

Experimental setup:
Exposing samples of kiwi concentrate to different light intensities for certain periods of time and measuring their sucrose concentrations before and after.

Independent Variable:
Light Intensity

Dependent Variable:
Sucrose Concentration

11. Effect of Potassium concentration on the growth rate of Raphanus sativus (Radishes)?

Experimental setup:
Planting and growing radishes within the same type of soil of different potassium ion concentrations

Independent Variable:
Potassium Ion Concentration

Dependent Variable:
Length of shoot and root of Raphanus sativus

12. Effect of temperature on the concentration of Vitamin C within various citrus fruits?

Experimental setup:
Extracting different citrus fruit concentrates such as grapefruits, oranges and lemons and heating these samples at different temperatures for a certain duration and measuring their Vitamin C concentration before and after.

Independent Variable:
Temperature Citrus Fruits

Dependent Variable:
Vitamin C Concentration

13. Investigating the effect of salt concentration on the germination rate of Raphanus Sativus.

Experimental setup:
Analysing and measuring the germination rate of Raphanus Sativus seeds(radish seeds) with provision of various concentrations of salt dissolved in water.

Independent Variable:
Concentrations of salt in water

Dependent Variable:
Rate of germination of Raphanus Sativus

14. To what extent does light wavelength and light intensity affect the rate of curdling of cow milk.

Experimental setup:
Placing various samples of milk underneath different light intensities(low, medium, high) and wavelengths(normal, no light, red, blue, etc.) for a duration of 2 hours and observing the rate of curdling by measuring the change concentration of lactic acid. The milk is curdled by first heating the milk until it comes to a boil and then placing a fixed amount of curd into the samples.

Independent Variable:
Light wavelength Light Intensity

Dependent Variable:
Change in concentration of Lactic acid in cow milk

15. Examining the relationship between the concentration of carbon dioxide and the rate of photosynthesis in Elodea.

Experimental setup:
Measuring the effect of various concentrations of carbon dioxide on the photosynthesis of samples of Elodea for a certain duration of time.

Independent Variable:
Carbon dioxide concentration

Dependent Variable:
Rate of photosynthesis(Amount of oxygen and glucose produced)