What happened to the test charge when brought near another positive charge, and how did you use this fact to score a goal only using positive charges? Explain for both the practice charge and more difficult levels.

Explanation:

As the like charges repel and opposite charges attract each other. When we bring the test positive charge near to the positive charge then it will move away. If one want to score a goal then he/she has to bring the positive charge behind the test charge, repulsion will cause the test charge to move away from the positive charge and it will go into the goal.

As far as difficult levels are concerned you should put the positive charges outside the path which you want your test charge to take. Hope you understand it.

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 : )