The internal structure of protons and neutrons can be explored through a branch of physics called particle physics. In particular, scientists have developed a model known as the quark model to describe the substructure of these particles. However, directly "seeing" inside a proton or neutron in the same way you would observe an everyday object is not possible due to the limitations imposed by quantum mechanics.
Protons and neutrons are composed of elementary particles called quarks held together by the strong nuclear force. The quark model describes protons and neutrons as being made up of three quarks each. Protons consist of two up quarks and one down quark, while neutrons consist of two down quarks and one up quark. The strong force is responsible for binding the quarks together.
To probe the internal structure of protons and neutrons, scientists use high-energy particle accelerators. These accelerators accelerate particles, such as electrons or protons, to high speeds and then collide them with the target particle, like a proton or neutron. By studying the products of these collisions, scientists can infer information about the internal structure of the target particle.
For example, in electron-proton scattering experiments, high-energy electrons are fired at protons, and the scattered electrons are detected and analyzed. By studying the angles and energies of the scattered electrons, scientists can obtain information about the distribution of electric charge and magnetic properties inside the proton.
Another technique used is deep inelastic scattering, which involves shooting high-energy electrons at protons or neutrons. By analyzing the scattered electrons and their energy loss, scientists can infer the presence and properties of the constituent quarks inside the target particle.
It's important to note that in these experiments, the protons or neutrons are not destroyed. However, the interaction between the probing particles and the target particles can impart energy and momentum, potentially changing the internal state of the target particle. Nevertheless, these experiments provide valuable insights into the structure of protons and neutrons without completely destroying them.