50 Fun Facts About Middle School Science

Which quantity, half the mass times the speed squared, quadruples when a car doubles its speed?

Kinetic energy rises with the square of speed, so doubling speed gives four times as much; Gravesande showed this by dropping weights into clay, where the dent grew with the square of impact speed.

What causes thunder, the rumble or crack that reaches you a few seconds after a flash in a storm?

Lightning rapidly heating air is the whole story: the sudden jump in temperature and pressure makes the air along the bolt expand explosively, and that shock reaches your ears as sound.

Which Jupiter storm, watched since 1831, has been shrinking for a century from three times Earth's width?

The Great Red Spot was about three times Earth's diameter a century ago, when it stretched some 40,000 km across, and nobody is sure why it keeps shrinking.

Which phase change makes frost by turning water vapour straight into ice, skipping the liquid stage?

Deposition is sublimation run backwards, and it is how hoar frost grows its feathery crystals on leaves and windows during clear, cold nights.

Which afternoon wind blows from the ocean onto the coast because land warms faster than water?

A sea breeze flips after sunset into a land breeze, because dry land also cools faster than water once the Sun stops shining on it.

Which moon of Saturn is the only moon known to have an atmosphere denser than Earth's?

Titan's thick nitrogen-and-methane air hid its surface until the Cassini–Huygens mission arrived in 2004 and found lakes of liquid hydrocarbons near its poles.

Which windiest planet was first seen in 1846 within a degree of the position Le Verrier calculated?

Neptune was the first planet found by calculation rather than by chance, and its storms are driven by sustained winds of up to 2,100 km/h, the fastest of any planet.

Which point on Earth's surface lies directly above the underground point where an earthquake starts?

The epicenter is not where the rock actually breaks: that point, the hypocenter or focus, can lie hundreds of kilometres down, and the epicenter is only its shadow on the map.

What curve did Galileo show a thrown ball traces through the air, if air resistance is ignored?

A parabola is what steady sideways motion plus an accelerating fall adds up to, and Galileo proved the shape in 1638 with his principle of compound motion.

Which dye extracted from lichens turns red in acid and blue in alkali when soaked into test paper?

Litmus is a mixture of dyes from lichens and only changes colour across a pH band of roughly 4.5 to 8.3, so it gives a quick yes-or-no rather than a precise reading.

Which long, slender projection of a neuron carries electrical impulses away from the cell body?

An axon can be a metre long for a single cell: the longest in the human body run in the sciatic nerve from the base of the spinal cord to the big toe.

Which finger-like projections lining the small intestine multiply its surface for absorbing food?

Villi are carpeted in turn with microvilli about a thousand times shorter, so the gut wall stacks surface on surface to pull nutrients out of passing food.

Which process, driven only by a concentration gap, moves oxygen from lung air sacs into blood?

Diffusion needs no pump and no fuel from the cell: particles simply spread from where they are crowded to where they are sparse, and in the lungs that happens across an extremely thin lining.

Which enzyme, activated by stomach acid, begins chopping proteins into smaller peptides?

Pepsin is made and stored as harmless pepsinogen so it cannot digest the stomach lining that produces it, and it only switches on when it meets hydrochloric acid in the stomach.

Which pair of structures bordering each pore on a leaf's surface swell and bow apart to open it?

Guard cells are ringed with cellulose fibres that stop them getting fatter, so when they take in water they can only lengthen, bowing apart like two sausages to open the pore.

Which Flemish chemist weighed a willow and its soil for five years, finding the tree gained 74 kg?

Jan van Helmont also gave science the word 'gas', from the Greek chaos, and since the soil had lost only 57 grams he credited the willow's growth entirely to the water he added.

Which process lets microbes at deep-sea vents build food with no sunlight at all, oxidising hydrogen sulfide instead?

Chemosynthesis was suggested by Sergei Winogradsky and confirmed only about 90 years later, when hydrothermal vents found in the 1970s turned out to be crowded with animals fed by sulfur-eating bacteria.

Which waxy film covering the outer skin of a leaf stops water escaping and blocks fungal spores?

The cuticle's micro-texture also keeps rainwater, dirt and microbes from clinging, and the self-cleaning leaves of the sacred lotus are now copied in engineered materials.

Which quantity, mass multiplied by velocity, keeps the same total when two billiard balls collide?

Momentum is conserved in any closed system, which is why a rocket must throw exhaust backward to move forward and a fired rifle kicks back into your shoulder.

At sea level and standard pressure, water boils at what temperature on the Fahrenheit scale?

212 °F sits exactly 180 degrees above water's freezing point of 32 °F, so one Fahrenheit degree is 1/180 of that span, against 1/100 for Celsius.

Which property, high for syrup and low for water, measures how strongly a liquid resists flowing?

Viscosity is the everyday idea of thickness made precise, and for liquids it typically drops as they warm, which is why cold honey barely moves and warm honey pours.

Which liquid property, pulling the top layer as tight as possible, lets water striders stand on ponds?

Surface tension also lets a razor blade float and pulls a free droplet into a sphere, because the same tug that holds up a water strider squeezes liquids into the least area they can manage.

Which count, written as a superscript left of an element's symbol, totals its protons and neutrons?

Mass number is always a whole count, so carbon-14 has exactly 14 nucleons, whereas an element's atomic weight is an abundance-weighted average of its isotopes and is rarely a whole number.

Whose 1913 atomic model put electrons in fixed orbits round the nucleus, like planets round the Sun?

Niels Bohr's model allowed electrons only certain energies, and it swept aside a zoo of earlier pictures including Thomson's plum pudding and Nagaoka's Saturnian atom.

Which English chemist who first described his own colour blindness founded modern atomic theory?

John Dalton's red-green colour blindness is still called Daltonism in several languages, and a 1995 examination of his preserved eyeball confirmed he lacked the green-sensitive pigment.

What inward pull, aimed at the centre of the curve, keeps a ball whirled on a string moving in a circle?

Centripetal force is Latin for 'centre-seeking', and because it always acts at right angles to the motion it keeps changing a body's direction without ever changing its speed.

Which support push, at right angles to a tabletop, stops a book resting there from sinking through?

Normal force takes 'normal' in the geometric sense of perpendicular rather than 'ordinary', and on a slope the ground's push splits into this component and a sideways one along the hill.

Which resistance between surfaces at rest, larger than once they slide, must be overcome to budge a crate?

Static friction is nicknamed 'stiction', and for most pairs of surfaces its coefficient is larger than the sliding one, which is why a stuck drawer flies open the instant it gives.

What does a drawn bow, a loaded catapult and a rock on a cliff edge all store, ready to be released?

Potential energy was named by the Scottish engineer William Rankine in the 19th century, echoing Aristotle's idea of potentiality, and the rock's share is gravitational while the bow's is elastic.

By which method does heat travel from an electric hotplate into the base of a saucepan sitting on it?

Conduction is heat diffusing through materials in direct contact, so the saucepan's base warms first and its handle last, while convection stirs the soup inside and radiation is the glow you feel from the ring.

Which Italian built the first steady-current battery in 1800 from stacked zinc and copper discs?

Alessandro Volta built his pile to settle an argument with Luigi Galvani, who believed twitching frog legs proved 'animal electricity', and the SI unit of voltage, the volt, is named in his honour.

Which unit of heat, warming one gram of water by 1 °C, is the one on food labels in kilo- form?

Calorie on a US food label actually means a kilocalorie, a thousand of the small calories that physicists and chemists mean by the word, which is why a chocolate bar can claim 250 of them.

Marble, slate and gneiss belong to which rock type, forged from older rock by heat and pressure?

Metamorphic rock starts out as a 'protolith' that is cooked above about 150 to 200 °C, often under pressures of 1,000 bar or more, until its minerals rearrange without the rock ever really melting.

Which 1,200 km California fault marks where the Pacific and North American plates slide past each other?

The San Andreas Fault was only traced all the way into Southern California after the 1906 San Francisco earthquake, when geologist Andrew Lawson was tasked with finding where the shaking began.

Which weak upper-mantle layer, from the Greek for 'without strength', lets the tectonic plates drift?

The asthenosphere begins some 80 to 200 km down and reaches as deep as 700 km, and a small fraction of molten rock within it is enough to let it flow over geological time.

Which precipitation grows layered stones only where a thunderstorm's updraft can hold them aloft?

Hail gets bigger the stronger the updraft, so a supercell can keep giant stones airborne long enough to grow, while a weaker storm drops only small ones.

Which scale, devised in 1971 by an engineer and a meteorologist, rates hurricanes in five categories?

Saffir–Simpson tops out at Category 5, sustained winds of at least 157 mph, and it ignores rain and storm surge entirely, so a Category 2 hitting a big city can do far more damage than a Category 5 in open country.

Which rooftop instrument, often shaped as a cockerel, takes its name from the Old English word for flag?

A weather vane swings to point into the wind, and the cockerel became standard after Pope Gregory I called it the most suitable emblem of Christianity; the oldest surviving rooster vane dates from 820.

Which dwarf planet, the first object found in the asteroid belt, was announced in 1801 as a new planet?

Ceres was later demoted to an asteroid and then promoted again to the only confirmed dwarf planet inside the asteroid belt, and it is the largest such body without a moon.

Which volcano on Mars stands about two and a half times the height of Mount Everest above sea level?

Olympus Mons is 21.3 km high and roughly ties with Rheasilvia, a central peak on the asteroid Vesta, as the tallest mountain yet found anywhere in the Solar System.

What is the fixed pivot of a lever called, sitting between load and effort in a seesaw or crowbar?

The fulcrum's position decides a lever's type, and Archimedes is credited with the boast 'Give me a lever long enough and a fulcrum on which to place it, and I shall move the world'.

Which simple machine, found in a well windlass, pairs two discs of different sizes that turn as one?

Wheel and axle was one of the six simple machines named by Renaissance scientists, and the oldest surviving example, found at Ur in modern Iraq, dates to about 3100 BCE.

Which simple machine redirects a rope over a grooved disc, so that pulling down hoists a load up?

A pulley was one of the five simple machines listed by Hero of Alexandria in the first century AD, and ganged together as a block and tackle, several of them multiply the pull as well as redirecting it.

Which simple machine, a portable inclined plane, first appeared as the flint hand axe?

A wedge turns a push along its length into a splitting push sideways, which is why an axe head and a knife blade, two planes meeting at one edge, work the same way.

Tweezers and tongs, with the effort applied between the pivot and the load, are which kind of lever?

Third class levers can never multiply force, only speed and reach, because the effort always sits nearer the pivot than the load does; a fishing rod works the same way.

Which set of subjects in an experiment gets a dummy treatment or none at all, purely for comparison?

A control group lets researchers separate a drug's real effect from the improvement people report simply from being treated, and a single study may run more than one of them at once.

Which factor does an experimenter deliberately change, expecting a second measured one to respond?

The independent variable goes by many aliases, including predictor, regressor, explanatory variable and, in machine learning, feature, while the one that responds is the dependent variable.

What is a sham treatment, such as a sugar pill or saline jab, that stands in for a real drug called?

A placebo can work even when the patient knows it is fake, in what is called an open-label placebo, and its evil twin is the nocebo, where expecting harm produces real symptoms.

What is the curved top of water in a narrow glass tube called, read at its lowest point on the scale?

A meniscus curves downward in glass because water clings to the wall more strongly than to itself, and the same goes for sap, honey and milk in any container they can wet.

Which Dutch-British physiologist showed in 1779 that submerged plants bubble gas only in sunlight?

Jan Ingenhousz identified the bubbles as oxygen and so supplied the piece Priestley had missed: that sunlight, not merely greenery, drives the whole process.