Quark model Puns

From my understanding, quarks can't be directly observed, but they were hypothesized (for some reason) because physicists kept finding new subatomic particles

Physics history ends in high school at roughly the "electron cloud" model of an atom and gives the impression that's where our understanding is and that there are no open questions. Obviously, that's not true.

1. What was insufficient about our understanding of the atom that led us to start developing models beyond protons/neutrons/electrons?

2. How were other particles in the standard model discovered? How did physicists know they had actually found new subatomic particles and not just exotic states of protons or something? Or maybe things that weren't particles at all?

3. Why did the discovery of other subatomic particles cause people to doubt that they were fundamental and must have been composed of something else (i.e. quarks)?

4. What questions did quarks answer that physicists had been puzzling over around that time?

5. What experimental evidence exists the supports the quark model?

6. What are some of the major open questions still out there about the standard model and quark model?

Hi, this is my first time posting here. I'm in year 1 UG and I'm writing a paper on unitary symmetries and the quark model. I'm having trouble figuring out why the SU(3) Lie group, which is continuous, generates discrete particles which are organized into multiplets. The representation theory I've been trying to read about it a little over my head. Can anyone help me to understand how exactly the hadron multiplets arise from SU(3)? Thanks so much.

I recently saw that the Higgs Boson has been discovered and I always thought it had something to do with string theory however Wikipedia said something about Quarks and the Standard model, could someone ELI5?

I'm looking for an alternative to the old FourSevens Quark. I want a simple press for instant on and click for constant on tail, and then easy switch between high and low by twisting the head. Flexibility as far as batteries, clips, etc would be nice too. Any options out there? Seems ridiculous that Surefire sued them and yet offers nothing comparable.

In school I was always taught that an atom is simply made up of protons, neutrons and electrons. Why is it that modern physics has strayed from that model and developed the much more complex model that is currently accepted.

Is it certain that all of these particles and antiparticles actually exist (i.e. take up physical space) or are they merely a means of explaining the behavior of atoms?

What motivated physicists to develop this standard model in favor of the simple proton-neutron-electron model? Is the classical model inadequate in explaining certain phenomena?

Are physicists certain that things like the neutron and proton are made of quarks?

I thought the electron was 3 quarks as well, but now I am reading it is a lepton and equally fundamental as a quark... which i find confusing and I'm not even sure what to ask.