Ногоон лонх

Mr Owen sets a tall jar of harbour water on the science bench. The water is green, and something inside it is moving. Sara and Ben lean over the glass. “Do you know what that is?” Sara asks.

Ben believes the green colour comes from the old works up the coast. “The river carries their emission down to us,” he says. Mr Owen writes the idea on the board without a word. He taps the chalk twice. “We test a hypothesis here, and we do not shout one across the room.”

Sara holds the jar up to the window light. “I think it is bacteria,” she says. Ben is still thinking about the works, but he writes the probability down anyway.

Mum comes up from the clinic with a brass lens and a flat box of slides. She does not believe the emission story at all. “A leak like that contains acid,” she says. Mum sets the lens down beside Sara. “It belongs to the clinic, and I am seeing a patient at six.”

They observe one drop under the lens together. “I see small green cells in neat rows,” Sara says. Thin threads of oxygen rise past the cells and break at the top of the drop. Ben counts the bubbles under his breath. “Does the water contain anything else?” he asks.

Ben tries again. “Radiation makes things glow, and this glass glows in the sun.” Mr Owen holds a small meter over the jar. It does not detect anything, and the needle stays at zero.

Mum turns the lens towards the window and smiles. “These cells own no secret at all,” she says. She hands the lens to Sara. “They are the weed that grows on every harbour wall.” Sara laughs and looks at Mr Owen. “So we spent an hour on ordinary green weed?”