What is a capacitor?
a passive two-terminal electrical component used to store electrical energy temporarily in an electric field.
Are there any other names for it?
a condenser
What's the difference between it and a resistor?
Unlike a resistor, an ideal capacitor does not dissipate energy.
Does it do something else instead?
It stores energy in the form of an electrostatic field between its plates.
How many plates does a capacitor have?
at least two
Are they kept apart by something?
a dielectric
What's that?
an insulator that can store energy by becoming polarized
What kinds of things can a plate be?
thin films, foils or sintered beads of metal or conductive electrolyte, etc.
What are dielectrics made of?
glass, ceramic, plastic film, air, vacuum, paper, mica, or oxide layers, among others.
What are capacitors used for?
parts of electrical circuits in many common electrical devices.
What is the dielectric for?
It acts to increase the capacitor's charge capacity.
What happens if you attach a battery to a capacitor?
eventually, no current can flow through the capacitor.
Is there a  way to avoid that?
a time-varying voltage applied across the leads of the capacitor
What happens then?
a displacement current can flow.