Zoe's Last Statistic
Last April, a forty-second video about the tap water in a small town was shared eleven thousand times in four days. In it, a man holds a paper test strip under his kitchen tap. The strip turns orange. “Ask yourself why nobody is telling you about this,” he says.
Zoe Andersen is sixteen. She watched the video, and then she watched her mother start buying bottled water for the house. That is how Zoe chose her science-fair project.
The video says the orange strip proves there are chemicals in the water. In reality, that kind of strip measures hardness — the amount of calcium and magnesium in the water. The town's water is hard: Zoe measured about 140 milligrams per liter in twelve samples from six houses. Hard water turns the strip orange. Therefore the strip indicates calcium, not poison.
The video says the water smells like a swimming pool, and that this is a warning. In reality, chlorine is added on purpose, because it kills bacteria. The town's water reports are published online every month, and Zoe read three years of them. The chlorine is measured at about 0.6 milligrams per liter. The legal limit is 4.0.
The video says bottled water is safer. Zoe tested six brands from the store on Main Street. Three of the six were harder than the tap water, and all six cost hundreds of times more per liter than the water in her own kitchen.
None of this is a theory. It is eleven pages of numbers, and anybody in the town can go and measure the same things in an afternoon.
At the bottom of her poster, Zoe put one last statistic, and it isn't about water. The video has been watched 412,000 times. Her poster was read by about sixty people, and eleven of them were judges.