Showing not Telling: Infodumps

At one point or another, you have to explain some aspects of your book. Even if the character knows exactly what’s going on, the reader might not. Put simply, an infodump is a large chunk of necessary information that bores the reader to death. I don’t know about you, but when I come across blocky paragraphs describing the scenery, my eyes tend to skim.
So how do we present crucial information by showing instead of telling?

Dialogue
One of the best ways to present facts is through characters talking to each other. But even this can be botched if the dialogue if nothing more than an infodump with quotations. Let’s compare;

Infodump
The alchemist selected a jar, filled to the brim with mercury. Mercury is a silver metal with a high density. It’s a liquid at room temperature, but exists in the solid cinnabar. Cinnabar is a powdery, red mineral that’s extremely poisonous when inhaled. Mercury was once thought to cause longevity. It is toxic and has been known to cause insanity. It was this material that the alchemist chose to work with.

Infodump with Quotations
The alchemist selected a jar, filled to the brim with mercury. He turned to his apprentice and explained, “This is mercury. Mercury is a silver metal with a high density. It’s a liquid at room temperature, but exists in the solid cinnabar. Cinnabar is a powdery, red mineral that’s extremely poisonous when inhaled. It is toxic and has been known to cause insanity.”

Face it; the second’s not much better. If you choose to do dialogue, make it a conversation;

Conversation
The alchemist selected a jar, filled to the brim with a silvery liquid. The apprentice craned his neck to see. “What’s that?”
The alchemist grunted and held the jar out for the apprentice’s inspection. “This, boy, is mercury.”
“And, uh, what exactly is it for?”
“Some believe it has the power to make you immortal.”
The apprentice’s eyes widened.
“Of course,” snapped the alchemist. “That’s utter rubbish. Far too many emperors have died because of that supposition. Everlasting life indeed. Mercury will kill you, boy. If it doesn’t drive you insane first.”
The apprentice looked warily as the sloshing metal. “Right. Well then, is there anything else we can use for the recipe…a substitute maybe?”
The alchemist laughed. “Closest thing you’ll get is cinnabar. But that’s got mercury in it anyway. Highly toxic. Take a whiff of that stuff and you’re a goner."

Thoughts
This only works if you’re using first person or third person omniscience POV. A character’s thoughts can be a powerful tool.

Before:
The day was bitterly cold. A crisp wind blew garbage across the street. Everyone was inside, enjoying the warmth of a fire. The entire sky was coated in white snow-clouds and it was only a matter of time before a blizzard hit. Even the queen’s palace was suffering from the icy weather, with servants scraping away at the frost-coated windows so the queen could enjoy looking outside.

After:
I marched down the slushy street, my woolen cloak wrapped tightly against the crisp winter wind. I was the only one outside. Every other sane person was indoors, tucked in a quilt by a blazing fire. But not me, I had a job to do. I groaned inwardly and kicked at a pile of frozen garbage. Blast this weather. I glanced up at the leaden sky blanketed with snow clouds. We’d have a blizzard before the month was out, for sure.
Another gust of wind sent me hurrying down the road again. I passed the queen’s palace and snickered at the poor, frozen guard on duty. The Queen didn’t much care about other people’s discomfort, evident by the army of servants scraping frost off the palace’s two-hundred-and-ten windows. Poor suckers. What was even the point of it? So that the queen could look outside and see the empty street?

Actions
The way characters behave can strengthen both Dialogue and Thoughts, and make a strong support on its own.

The alchemist selected a jar, filled to the brim with a silvery liquid. The apprentice craned his neck to see. [This reveals that the apprentice is curious and new to the alchemy experience] “What’s that?”
The alchemist grunted [Not the friendliest guy] and held the jar out for the apprentice’s inspection. “This, boy, is mercury.”
“And, uh, what exactly is it for?”
“Some believe it has the power to make you immortal.”
The apprentice’s eyes widened. [He’s naïve to believe such a myth]
“Of course,” snapped the alchemist. “That’s utter rubbish. Far too many emperors have died because of that supposition. Everlasting life indeed. Mercury will kill you, boy. If it doesn’t drive you insane first.”
The apprentice looked warily as the sloshing metal. [Now he’s nervous] “Right. Well then, is there anything else we can use for the recipe…a substitute maybe?”
The alchemist laughed. [He’s got a strange sense of humor] “Closest thing you’ll get is cinnabar. But that’s got mercury in it anyway. Highly toxic. Take a whiff of that stuff and you’re a goner.”

The apprentice’s reactions give us a clear definition of who he is without having to say, “The new apprentice didn’t know anything about alchemy and was incredibly gullible.”