There are plenty of different topic ideas that can be used for a science fair project.
Human behavior is a fantastic topic to use. With this topic, you can discover more about how people think, how their memory works and even what motivates them. One such project idea that fits into this category is a test which would aim to find out if a subject’s favorite color will influence his or her decisions when making choices from a selection. Essentially this experiment will try to establish if a person’s colour preferences will bias their fine motor skills when performing quick, repetitive tasks.
A really fun area to base a project around is the science of cooking. And a good test within the cooking science topic is this one: You may be aware that yoghurt contains bacteria. But how about performing a test to see if there really is bacteria living in yoghurt? To do this test you will need quite a few things, and it is a somewhat more long-winded experiment than many of the others but is also probably one of the more interesting ones. There are quite a few steps to follow so it might be a good idea to consider buying one of the many science project kits that will contain everything you need for the project along with full instructions.
Earth and Environmental Science has some really interesting areas of study. For example, if the weather is good and getting to a beach is a possibility there are some very good project ideas that can be used. For instance, how about trying to find out how salty the sea is? A good way to approach this one is to compare the saltiness of the sea with other types of water. This is a more straightforward task and only a few materials, weighing equipment and a written table are all that will be required, along with of course a few different water samples. There are plenty of guides online to help you find out how to test the salinity of the water.
Plant biology gives us plenty of interesting project ideas. You can try and find out if aloe juice is able to stop strawberries from going moldy. The best way to accurately compare the effects of the aloe juice on the strawberries is to have one sample of strawberries with aloe juice washed over them, and one lot of strawberries with just a plain-water wash. Compare over time and see which goes moldy first.
Hopefully, you will have gained a few science fair project topic ideas that you will try out at some point. This is of course just the tip of the iceberg as there are many other very interesting topics to base a science project around, as science is a very broad subject with an enormous amount to study.