What might cause a theory to change over time?

A theory does not change into a scientific law with the accumulation of new or better evidence. A theory will always remain a theory

Explanation:

theories and laws could potentially be falsified by countervailing evidence. Theories and laws are also distinct from hypotheses.

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 : )