The first scientists to suspect the existence of dark matter were puzzled because galaxies

i guess that visual aids present persuasive examples to what you are presenting, some factors would be theme (does it fit with the color, information, what you are presenting), size (can you see it, is it a big enough span of data/information), and overall look of the visual aid.

hope this : )

beta is electron from nucleus

something from nucleus has changed, but charge must be same for cons of charge

0.93xc=0.93x3x10^8m/s

2.54cm is 1 inch

360seconds i 1 hr