Mom cleared off the kitchen counter. “Can you grab two bowls that are the same size and a measuring cup, Zoey?”
Mom said the best way to explain what salt does to plants was to do a science demo (that’s short for demonstration). I set the bowls and measuring cup next to our saltshaker, and Mom brought several thin circles she’d sliced from a potato. They looked like weirdly flat and juicy potato chips.
Mom cleared her throat. “OK, so let’s see what happens when we add salt to one potato slice and not another. Remember, when we do an experiment, we always—”
“Change one thing! And keep everything else the same!” I interrupted, and Mom laughed.
“Exactly, so we’re changing . . .”
“Salt! So we should do the same-sized potato slices in each bowl, and add the same amount of water to both.”
“Excellent!” My mom smiled and handed me the measuring cup. The bowls were pretty big, so I decided to add two cups of water to each. Then I chose two thin potato slices that looked identical and put one in each bowl.
Mom unscrewed the lid to the saltshaker and handed it to me.
“All of it?” I asked.
She nodded. I poured all of the salt into just one of the bowls and stirred the water, salt, and potato slice together.
“Are you sure about this?” I asked, looking into the bowl. “It’s just a slice of potato, not a plant.” A catnip plant and a potato slice seemed pretty different to me. So maybe the catnip plants would be just fine.
“In this demo, the slice represents the whole plant. So even though the potato slice is just a part of a potato plant, it’ll show you what all the parts of any plant would do in this much salty water.”
Oh. Well . . . maybe the potato slice wouldn’t change much? I hoped. I really wanted the catnip plants to be fine. Once the caterfly eggs hatched, they’d be hungry for those leaves!
Mom set a timer for thirty minutes. “Now we wait.”