The weak force is one of the Four Fundamental Forces of the universe. Just like with the strong and electromagnetic forces, to fully understand this force we’ll need to start with energy. Energy takes the form of strings that resonate a specific harmonic frequencies. The specific frequency determines what we label the particle and its attributes.
A hadron is a collection of 3 quarks, and quarks have an attribute that we call flavor. The majority of quarks have either an up or down flavor. Two up quarks and one down quark make a proton which has a charge of +1. Two down quarks and one up quark form a neutron which has no charge.
A smaller string called a neutrino also has no charge. These things are so small that they can fly through the empty space between the nucleus and electrons inside an atom!
A neutrino passing close to a neutron in the nucleus of an atom will emit an even smaller string that we call a boson. The frequency of the neutrino has now changed since it gave up the energy to form that boson. The neutrino now has the frequency of an electron. The boson is absorbed by one of the down quarks in the neutron to give it the frequency of an up quark, changing the neutron into a proton. This is the weak force.
Naturally, this tendency is very energetically stable since it allows for the destructive interference between charges. The neutrino now has the attributes of an electron (-1 charge) and it is now attracted to the newly formed proton (+1 charge) via the electromagnetic force. A proton and electron forms a stable hydrogen atom with a neutral charge.
This may have been how the first atoms formed since it is much more likely the strings condensed into hadrons without charge, though we don’t have direct evidence of this yet. A charged hadron requires destructive interference from an opposite charge, so the theory seems likely.
Neutrinos, because of their small size and lack of charge, are able to fly right through matter. Remember, the universe is mostly empty space, the space within an atom is no exception.
Neutrinos are constantly being given off by stars all throughout the universe, among other particles. Within a single second, about 10,000 of them just flew through your skull. Don’t worry, they have no charge or mass so they can’t hurt you.
The only things that neutrinos will interact with is the down quarks of a neutron if they manage to get close enough to one. If it does, the weak force will occur, changing the neutrino into an electron while the flavor of a down quark changes to an up quark.
If the addition of an extra positive charge disrupts the stability of the nucleus, the atom will split releasing a large amount of energy. The energy will then be absorbed by nearby atoms and start a positive feedback loop of nuclear fission.
Sometimes, the split will only expel a stable helium atom or a high energy electron in order to stabilize the energy of the nucleus. Other times, the entire nucleus will split apart to form two stable atoms with approximately half of the total hadrons each. This is called nuclear decay and we use it to find the age of very old things, like the Earth itself.
Because of the nearly constant stream of neutrinos flying around, we can assume rates of decay are constant as well. Some atoms have more neutrons than average, and the excess of neutrons makes them more susceptible to the weak force. Atoms with more hadrons in its nucleus, making it larger, also are more likely to experience the hadron switch.
Based on the trillions of neutrinos passing through our planet every second, we have come up with a method of determining the time it takes for the nuclear decay to occur. We came up with a measure that we call half-life and it gives us the ability to very accurately find the age of many ancient objects.
We live in a world that has a specific set of rules. If we are willing to sit down and try to learn those rules, we can find the answer to any question we can possibly ask about our universe. All you need to do is keep asking questions and we all get smarter.