Why do people walks bare feel pain

As we age the fat pad underneath the bones at the front of our feet (metatarsal heads) and under the heel bone become thinner or “migrate” away from where they are most needed

what experimental evidence led scientists to change from the previous model to this one?

a few of the positive particles aimed at a gold foil seemed to bounce back.

the colors of light emitted from heated atoms had very specific energies.

experiments with water vapor showed that elements combine in specific proportions.

cathode rays were bent in the same way whenever a magnet was brought near them.