Tag: science & technology

Pheromones are chemical signals detected through the olfactory system (smell), which is why they trigger instinctive responses. While some animals use taste (the vomeronasal organ), smell is the primary human sense for pheromone detection.

Arachnids are eight-legged arthropods including spiders, scorpions, ticks, and mites. Cockroaches are insects (six legs), making them the correct answer for 'not an arachnid'.

Substances with pH below 7 are acidic because they have a higher concentration of hydrogen ions (H+) than pure water. A base would have a pH above 7, while pH 7 is neutral.

Edwin Hubble provided the first observational evidence that there are galaxies beyond the Milky Way in the 1920s by showing that spiral nebulae were actually distant galaxies, not nearby gas clouds.

Asteroids are rocky objects orbiting the sun that are too small to be considered planets, which is why they're historically called minor planets. They're primarily found in the asteroid belt between Mars and Jupiter.

Chatoyancy is the optical phenomenon where a gemstone displays a narrow band of reflected light that resembles a cat's eye. The most famous chatoyant gemstones are chrysoberyl cat's eye and tiger's eye quartz.

Seaborgium (Sg) is a synthetic element with atomic number 106, classified as a transition metal in group 6 of the periodic table. It's named after Glenn T. Seaborg and does not occur naturally.

The 'turn your head and cough' test is a standard physical examination technique for checking inguinal hernias. Coughing increases abdominal pressure, which can cause a hernia to bulge and become detectable to the doctor.

A shooting star is actually a meteor - a small piece of rock or dust burning up in Earth's atmosphere. As it enters the atmosphere at high speed, friction causes it to glow and create a visible streak of light.

Acid rain typically has a pH between 4 and 6, which is below the neutral pH of 7. This acidity comes from sulfur dioxide and nitrogen oxides reacting with water in the atmosphere to form sulfuric and nitric acids.