Trivia question of the day

Answer: Movement irritates the sensitive lining of the abdominal wall

Irritation of the lining of the abdominal wall is a plausible explanation that fits many features of side stitches. This lining can produce sharp, localized pain when irritated, but the exact cause of exercise-related side stitches remains unsettled.

Answer: Ice is less dense than water

Correct! Lakes freeze top-down because ice floats. Water is most dense at 4°C, and as it cools further it becomes less dense. At 0°C it freezes into ice, which is even less dense, so it floats on the liquid water below. That floating ice insulates the deeper water, keeping it liquid so fish can survive. If ice sank, lakes would freeze solid and aquatic life would be impossible.

Answer: A protein in the muscles stores oxygen for use during a dive

Whale muscles contain abundant myoglobin, a protein that binds and stores oxygen. That reserve can support muscle activity during a dive. Blood also carries oxygen, so muscle storage is one part of a broader diving adaptation.

Answer: Red glass only transmits red

Correct! Colored filters work by selective absorption. Red glass absorbs blue, green, and other wavelengths, transmitting primarily red (~620-700nm). When you look through it, only red light reaches your eyes from objects. Red objects stay red, but blue objects appear black (no blue light transmitted). It's subtractive color filtering!

Answer: Blood vessels rapidly change

Correct! Cold food touching the roof of your mouth causes blood vessels to rapidly constrict then dilate. This triggers pain receptors. Your brain interprets this as head pain. Pressing your tongue to the roof of your mouth can help!

Answer: Repel biting flies

Correct! Experiments with striped coats on horses found far fewer successful horsefly landings, so stripes give flies fewer chances to bite and spread disease. Exactly how the pattern disrupts a fly's approach is still being studied; the measured effect is on landings, and other stripe benefits remain debated.

Answer: Sulfur in the air reacts with silver atoms on the surface

Correct! Trace amounts of hydrogen sulfide gas (H₂S) float in the air—from eggs, rubber bands, car exhaust, and natural sources. When these sulfur compounds land on silver, they react with the silver atoms to form silver sulfide (Ag₂S), a black compound. This black layer builds up gradually. This explains why silver tarnishes faster near rubber, eggs, or in polluted cities. Gold doesn't tarnish because it's too chemically stable to react with sulfur. You can remove tarnish by polishing (grinding it off) or using aluminum foil with baking soda (which chemically reverses the reaction).