you could get a couple different plants and see which one grows best with different types of liquids such as water, pop, and juice
can plant better grow
How the heart works.
bread
Egg flotation, exploding volcancoes.
on youtube there is a channel that does science its called mystery science
Look in the back of each chapter of the science book. They often have suggestions.
Science fairs are very common in fifth grade. Some of the most common include a potato/copper battery, volcano, hydroponic experiments and a mouse-in-a-maze experiment.
You can say: does the mass of an object affect how far you throw it
The grade is up to how diligent you are. Below are some sites that have lots of science fair projects.
test plants with different light sources
I would say a rube goldberg machine
Children need to know this for science projects in the 8th grade. If some intelligent person would answer this it would be greatly appreciated.