Simplify the following text for a Grade 8 native English-speaking person.
Original: This hypothesized force was called the strong force , which was believed to be a fundamental force that acted on the nucleons ( the protons and neutrons that make up the nucleus ) . Experiments suggested that this force bound protons and neutrons together with equal strength .
Simplified: Residual strong force is the type of strong force that acts between hadrons ( protons and neutrons ) .