AwesomeScience

Guess the element — Expert, Keen, Everyday. Try to land it in three. 1/4 Expert: 1. In the 1880s French vine growers began spraying a blue mix of its sulfate and lime — the Bordeaux mixture, one of the first widely used fungicides. 2. Horseshoe crabs and octopuses have blue blood, because their oxygen-carrying protein holds atoms of this metal instead of iron. 3. Ötzi the Iceman, frozen in the Alps about 5,300 years ago, carried an axe whose blade was nearly pure metal of this element.

1. In 1669, Hennig Brandt boiled down huge amounts of urine and distilled the residue, catching a waxy white solid. 2. Squeezed under high pressure and heat, it turns into a black, flaky form that looks and behaves a lot like graphite. 3. Its white form is made of four-atom pyramid-shaped molecules, melts near 44 °C and bursts into flame in air, so it is stored under water.

Test Dissection #3: Label every mistake with a cause Tonight: give each missed question one label, then match the fix. • Didn't know it → relearn the concept • Misread the question → underline key words (NOT, EXCEPT, units) next time • Careless slip → save a few minutes to check your work • Ran out of time → practice with a timer, and answer what you know first These labels are a teacher's tool, not a tested method. But the idea underneath, figuring out why you got it wrong, has support. In a study of 8th graders prepping for New York's Algebra 1 Regents exam, the more time teachers spent talking with students about why their errors happened and how to avoid them, the more they learned. Just walking through the right method didn't help. Next Thursday: what to write beside each mistake. Sources in the reply.

1. Freshly made atoms of it hitch a ride on tiny potassium chloride particles in a stream of helium, traveling tens of meters through a thin tube to the chemists. 2. Chemists prefer a 3.1-minute form of it over its longest-lived one, because it can be made in larger batches. 3. Ten minutes of three trillion light ions a second hitting a thin target yields only about 1,200 of its atoms.

1. Humphry Davy first isolated it in 1808 by electrolyzing a moist mix of lime and mercuric oxide into an amalgam, then boiling off the mercury. 2. Its compounds turn a flame a brick-red orange. 3. The silvery metal dulls in air and steadily frees hydrogen from cold water, leaving a strongly alkaline solution — eager, but far calmer than sodium.