What does a capacitor look like?

The physical appearance varies depending on the type of capacitor in question. The main similarity between the different types is that they have two leads.

Electrolytic Aluminum Capacitors come as metal cans in appearance, and can be radial (both leads at the bottom) or axial (one lead at the top, one lead at the bottom). This type of capacitor is also polarized and typically will have a symbol indicating which lead should be connected to ground (most common) or a symbol for the lead that connects to the voltage source. Typically there will be a capacitance rating in Farads on the capacitor.

Ceramic Capacitors come in many different appearances, one commonly found is a disc shape. These capacitors are not polarity sensitive and thus have no markings indicating polarity. They are smaller than Electrolytic Capacitors and usually do not have enough space to display a Farad rating but will use a numeric code (similar to color bands on resistors)

There are many other types of capacitors and also "homebrew" capacitors composed of soda bottles and tin foil, which makes giving an exact answer to "What does a capacitor look like?" difficult.