This is unquestionably the hardest part of any science fair project, so here are 3 strategies for finding an original idea, ranked from easiest (good enough) to hardest (best):
1. Find directions for a project online or in a science fair project book. Complete the project as it is because this is a good way to learn the scientific method. For your original project, you will need to change something about the one you found. For example: if the project was “what is the effect of pumpkin size (weight) on the number of seeds inside?” you could make an original project by asking any (or all) of the following questions:
What is the effect of pumpkin volume on the number of seeds inside?
What is the effect of pumpkin size on the average size of the seeds inside?
What is the effect of jalapeño pepper size on the number of seeds inside?
In all cases the independent variable (aka manipulated or explanatory variable) is the one you will manipulate (pumpkin weight, pumpkin volume, pepper size) and the dependent variable (aka response variable) is the one you will measure (number of seeds inside, size of seeds inside) in your experiment(s).
2. Find something to measure: You must measure something! Think about all the things you can measure:
For your DEPENDENT VARIABLE (must be quantitative), you could measure…
• frequency (how often something happens)
• angles and/or direction
The INDEPENDENT VARIABLE can be either quantitative (i.e. measurable with numbers) or qualitative (i.e. describable with adjectives).
Examples of qualitative variables would include:
• color: red, blue, green, yellow, orange
• gender: male, female
• size: small, medium, large
• age: old, young
Now that you have identified what you are able to measure, ask a question as to how that variable changes as a function of time (hourly, daily, weekly, etc.), or space (distance from something, distance along a path, within an area of interest, etc). Along the same lines, you could build a piece of equipment (just search for “how to build a” … thermometer, barometer, secchi disk, etc) as part I of the project and then use that equipment to answer a question as part II.
3. Find an observation: If you have a good understanding of the scientific method and are just searching for a creative idea, this is the strategy for you. Home remedies and “old wives’ tales” are a fantastic place to start. For example, I have too many spiders in my house and I once heard that spiders will not build webs near coconut oil.
This would be my observation. My question becomes: Do spiders avoid coconut oil? Can you make a hypothesis and design an experiment around this question? Try it before reading on.
Here are some hints: My hypothesis could be (I would have to pick one):
If there is coconut oil, then there will be fewer spiders
If there is coconut oil, then there will be more spiders
If there is coconut oil, then there will be no difference in the number of spiders
The hypothesis often yields clues about what the experiment will need to be. Here I would need well defined areas with and without coconut oil and then I would need to count the number of spiders that are in those areas. The details are up to you!