Grow It Lab

Little Thunder held up two paper cups of soil. "My bean will grow the tallest," he said. "I'm giving it a secret ingredient. Lemonade!"

Suzy tilted her head. "That's a prediction. A good scientist tests it."

"How?" asked Little Thunder.

Spike lined up four cups on the shed windowsill. "We plant one bean in each cup. Same soil, same sunny window, same amount to drink every morning. The only thing we change is what they drink."

"So two get water and two get lemonade," said Suzy. "That's a fair test. If we changed lots of things at once, we wouldn't know what made the difference."

Every morning they watered the cups. Every afternoon, Spike held the ruler while Little Thunder measured, and Suzy wrote the numbers in a chart.

On day four, two green loops pushed up through the water cups. The lemonade cups stayed bare.

"They're just shy," said Little Thunder.

On day eight, the water beans were six centimetres tall. One lemonade bean had finally poked up, small and pale.

Suzy drew the results as a bar graph. Two tall bars. One tiny bar. One empty space.

Little Thunder looked at it for a long time. "My prediction was wrong," he said quietly.

"That's not a fail," said Spike. "That's a result. Now we know something we didn't know before."

Brasilia the cow wandered over and sniffed the cups. "What about compost?" she asked. "My old vegie patch loved it."

Little Thunder's eyes lit up. "New prediction! Compost beans will beat plain soil beans."

"Then we need a new fair test," said Suzy, already fetching more cups.

This time, everyone drank the water.