1. Environmental Science: Compare plant growth using natural materials (coconut coir, peat moss, etc.) instead of commercial potting soil.
2. Chemistry: Investigate the effect of various household substances on the rate of eggshell dissolution.
3. Physics: Analyze how different types of surfaces (rough, smooth, reflective) affect the distance and pattern of sound waves.
4. Biology: Examine the impact of different light wavelengths (red, blue, green) on the growth of algae cultures.
5. Engineering: Build and test a solar-powered water heater to determine its efficiency in heating water for domestic use.
6. Psychology: Investigate the relationship between background music and concentration levels, using different genres and volume levels.
7. Computer Science: Develop a program to simulate and study the spread of a hypothetical infectious disease within a closed population.
8. Social Science: Analyze the correlation between smartphone usage and sleep patterns among adolescents to assess potential impacts on sleep quality.