Ask friends with different color hair to be your guinea pigs for this project. You will need someone with red, blond, black, brown and white hair. To add another layer, have people with straight, wavy and curly hair participate. Rub a balloon on fabric to create static and then place the balloon on each hair type. Take pictures of the results. Calculate how much hair sticks to the balloons based on hair type.
Gather salt, sugar and ice cubes. Place the ice cubes in plastic containers. Leave one ice cube empty; place a tablespoon of salt on the second and a tablespoon of sugar on the third cube. Set a timer to observe how long it takes for each cube to turn into water. Take pictures throughout the process for your display. When bringing this project to the fair, duplicate the process you performed at home. Guests will be able to see the ice cubes in their various states.
Since many children enjoy drinking soda pop, this project will likely be of interest to fourth graders. Place cola on different food items like meat or egg shells. In separate containers, create the control group and place the meat or eggshells into plain water. Observe the changes that happen gradually. Take pictures throughout the experiment to display with the project.
Create a science fair project that evaluates how different amounts of light affect the growth of plants. Decide what type of seed you will use, if the fair is coming up soon; use a fast-growing grass seed. Plant the same amount of seeds in four cups. Leave one cup uncovered and cover the next three cups with black construction paper. Punch a few holes in one cup and more holes in the third cup. Do not punch holes over the last cup. Water the plants the same amount each day. Record daily the differences in growth by observation.