Mineral
"What the hell is in this water?" Neil grimaced. He spoke under his breath, because their grandparents were hard of hearing, and he regularly took advantage of it, especially when something was truly disgusting.
It didn't matter that he was seven.
Adam shrugged, and sipped his own water experimentally. There was definitely a taste he wasn't used to. Like dirt. Or rocks.
"Why's your water taste like this, Gram?" he asked raising his voice.
"Like what?" she asked, coming over to more closely inspect the glass.
"There ain't nothing wrong with that water," their grandpa said proudly, smiling a little. "That's just minerals from the ground. They're good for you."
Adam stared at his little brother with huge eyes, and shook his head. Neil may have had the mouth, but Adam was in charge, and Adam decided that he would rather have him and Neil die of thirst than drink something that tasted more like outside than in.
Neil scooted his glass away with one finger.
When their grandparents weren't looking, Adam carefully evened out the glasses, so that the liquid was more equal.
"Grandpa, can we be excused? We were kind of in the middle of something outside before..." Adam hedged, trying to make whatever-it-was sound really important so they'd be allowed to go.
"Sure. You boys go play, but don't come back around here in five minutes saying you're thirsty. That's perfectly good water there. Your Grandma and I have been drinking it for 50 years."
Adam and Neil ran outside before they had to hear the end of his story. They could take a long time.
"We never play together," Neil pointed out, breathless, after he'd spit his water into the grass.
"I know," Adam agreed, wiping his mouth.
"It's not mean to put worms in the sun, I don't care what you say," Neil objected, anticipating Adam's argument.
"Why would you want to, anyway?"
"It's interesting. Duh!" Neil said, going to check on the small kitchen pot he had packed with dirt and the earthworms lying on top.
Adam sat on the edge of the sandbox, well aware that ten was too old to build sandcastles, but he didn't care. He was building a sand city. That was different. He was pretending to be an architect. He wished he had one of those yellow hats.
It would probably help him think better, too.
"Adam?" Neil called. "The worms are thirsty, so I think I'm gonna give 'em some hose water, okay?"
"Okay," Adam returned, counting down the seconds to when Grandma would notice what he was doing out the window and holler at him.
Three. Two. One.
"Neil, you get your mouth off that hose, before you get a disease!" she crowed.
Adam just laughed under his breath, and added more sand to his city.