50 Fun Facts About 11th Grade Science

Which gemstone, the hardest natural material, is made of the same element as pencil graphite?

Diamond is pure carbon, exactly like graphite, but its atoms lock into a rigid crystal. At room pressure graphite is the stable form, so a diamond is very slowly turning into it.

Which kitchen staple, formula NaCl, joins a soft reactive metal to a poisonous yellow-green gas?

Table salt is sodium chloride. Neither ingredient is safe alone: sodium is a soft, highly reactive metal, and chlorine was used as a poison gas in World War I.

Which precious metal has the chemical symbol Au, taken from the Latin name aurum?

Gold is the most malleable metal of all. A single gram can be beaten into a sheet covering one square metre, thin enough to become semi-transparent.

Which organelle, inherited almost only from the mother, makes the ATP that powers a cell?

The mitochondrion keeps its own small genome, similar to a bacterium's. That is a clue to its origin: its ancestor was a free-living microbe that fused with another cell long ago.

Which phenomenon makes an ambulance siren sound higher as it approaches and lower as it drives away?

The Doppler effect is named after Christian Doppler, who described it in 1842. Astronomers use the same shift in starlight to measure how fast stars and galaxies approach or recede.

Which physicist's 1905 equation E = mc² showed that mass and energy are two forms of the same thing?

Albert Einstein published it in 1905, his 'miracle year' of four landmark papers. Because the speed of light squared is so large, a small amount of mass holds an enormous amount of energy.

Which naturalist's voyage aboard HMS Beagle led to the theory of evolution by natural selection?

Charles Darwin sailed from 1831 to 1836 and came home puzzled by the wildlife and fossils he had collected. On the trip he also ate puma, iguana, armadillo and giant tortoise.

Which element, the lightest of them all, makes up about 75% of the universe's normal matter?

Hydrogen comes first on the periodic table, with atomic number 1. Counted by number of atoms rather than by mass, it makes up more than 90% of the universe's normal matter.

Which scientist, who named polonium after her native Poland, won Nobel Prizes in two sciences?

Marie Curie remains the only person to win Nobel Prizes in two different sciences. She was also the first woman to win one at all, sharing the 1903 physics prize.

Which Italian scientist is said to have dropped unequal weights from the Leaning Tower of Pisa?

Galileo Galilei's pupil Viviani told the story decades later, and most historians think it was a thought experiment. Its point: how long an object takes to fall does not depend on its mass.

Which SI unit, about 6.022 × 10²³ particles, do chemists use to count atoms and molecules?

A mole of anything is exactly 6.02214076 × 10²³ of it, a figure called the Avogadro number. Some chemistry classes celebrate Mole Day on October 23, written 10/23 in the US.

Which Russian chemist's periodic table predicted elements not yet discovered, such as gallium?

Dmitri Mendeleev claimed he saw the complete arrangement of the elements in a dream. He used his table to predict the properties of three elements nobody had found yet, scandium among them.

Which family of elements, including neon and argon, fills group 18 and almost never reacts?

The noble gases have a full outer shell of electrons, which leaves them little tendency to react. Neon's name comes from the Greek for 'new', and xenon's from the word for 'stranger'.

Which type of chemical bond forms when two atoms share pairs of electrons, as in a methane molecule?

Covalent bonding lets each atom reach the equivalent of a full outer shell by sharing electrons with a neighbour. Irving Langmuir introduced the word 'covalence' in 1919.

Which scale, devised by a Danish chemist at the Carlsberg Laboratory, measures acidity?

The pH scale is logarithmic, and pure water sits at a neutral 7 at 25 °C. Søren Sørensen never explained what his letter p stood for, and its exact meaning is still disputed.

Which kind of substance, such as an enzyme, speeds up a reaction without being consumed?

A catalyst comes out of the reaction unchanged, so it can be recovered and reused. An estimated 90% of commercially produced chemical products rely on one at some stage of manufacture.

Which term describes a reaction, such as burning fuel, that releases heat into its surroundings?

Exothermic comes from the Greek for 'outward' and 'thermal'. Condensation counts too: steam gives out heat as it turns back into liquid water.

What are atoms of one element, such as uranium-235 and uranium-238, that differ in mass called?

Isotopes share one spot on the periodic table, and the name is Greek for 'the same place'. It was coined in 1913 by Margaret Todd, a Scottish doctor and writer.

Which particle's count in the nucleus sets the atomic number and decides which element an atom is?

The proton count is the atomic number, which uniquely identifies an ordinary element. Chemists of the 1800s ordered the elements by atomic weight instead, the only thing they could measure.

Which New Zealand-born physicist's team found the atomic nucleus by firing particles at metal foil?

Ernest Rutherford likened the particles that bounced back to a 15-inch shell rebounding off tissue paper. New Zealand put his portrait on its hundred-dollar note in 1992.

By Newton's second law, force is mass times which quantity, measured in metres per second squared?

Acceleration is the rate at which velocity changes. The same law can be put another way: the net force on a body equals the rate at which its momentum is changing.

Which SI unit of energy is named after an English physicist who also managed his family's brewery?

The joule honours James Prescott Joule, a wealthy brewer's son. One joule is about the energy needed to lift an apple one metre.

What name is given to −273.15 °C, the lowest temperature theoretically possible?

Absolute zero can be approached but never reached. Scientists in Bremen have cooled matter to 38 trillionths of a degree above it.

Which unit of electrical resistance is named after the German schoolteacher behind the law V = IR?

The ohm honours Georg Ohm, who found that the current through a conductor is directly proportional to the voltage across it. Its symbol is the Greek capital letter omega.

Which form of energy, given by the formula ½mv², does any object have because of its motion?

Kinetic energy takes its name from the Greek word kinesis. Because speed is squared in the formula, a car going twice as fast carries four times as much of it.

Which property of a wave, measured in hertz, counts how many cycles pass a point each second?

Frequency is what mostly decides the pitch of a sound. Human ears typically pick up between about 20 Hz and 20,000 Hz, and the upper limit usually drops with age.

Which property, described by Newton's first law, keeps a moving object moving unless a force acts?

Inertia also keeps an object at rest sitting still until a force moves it. The word was taken from the Latin for 'idleness' or 'laziness'.

Which electromagnetic waves, first detected coming from radium, have the shortest wavelengths?

Gamma rays were discovered in 1900 by the French scientist Paul Villard. Earth's atmosphere screens out a large fraction of those that arrive from space.

Which bending of light, as it passes from air into water or glass, lets a lens focus an image?

Refraction happens when a wave changes speed as it crosses into a new medium. It is also responsible for rainbows, where raindrops split white light into colours.

Which measure of disorder, by the second law of thermodynamics, never falls in an isolated system?

Entropy was named by Rudolf Clausius, who built the term from a Greek word for transformation. The same law is why heat flows on its own from hotter things to colder ones.

Which British chemist's X-ray images of DNA at King's College London helped reveal the double helix?

Rosalind Franklin died of ovarian cancer at 37, four years before Crick, Watson and Wilkins shared a Nobel Prize for the structure. Her own notebook had recorded evidence of a helix.

Which pigment, a poor absorber of green light, lets plants capture the energy for photosynthesis?

Chlorophyll absorbs blue and red light most strongly, which is why leaves look green. Its name comes from the Greek words for 'pale green' and 'leaf'.

Which type of cell division produces egg and sperm cells with only one copy of each chromosome?

Meiosis takes two rounds of division and ends with four cells. Along the way, paired chromosomes exchange some of their genetic information, so the genes passed on are reshuffled.

Which Austrian friar worked out the basic rules of heredity by cross-breeding pea plants?

Gregor Mendel saw his results ignored by the scientists of his day. Three scientists independently confirmed them in 1900, after his death, and the modern age of genetics began.

Which process moves water across a cell membrane toward the side where more solute is dissolved?

Osmosis is spontaneous, so a cell spends no energy on it. The pressure it builds up inside cells is the main agent of support in many plants.

Which term describes a living body keeping conditions such as temperature relatively stable?

Homeostasis was coined in 1926 by the American physiologist Walter Cannon, from Greek roots meaning 'staying the same'. Blood glucose and blood pressure are regulated in the same way.

In a redox reaction, which process is the loss of electrons, as happens to iron when it rusts?

Oxidation originally meant reacting with oxygen to form an oxide, and the term later widened. Redox reactions can be slow, like rusting, or rapid, like burning fuel.

Which French chemist, guillotined in the Revolution, named oxygen and showed mass is conserved?

Antoine Lavoisier had bought a share in the Ferme générale, a company that collected taxes for the crown. He was charged with tax fraud, convicted and executed in 1794 with 27 co-defendants.

Whose gas law says a trapped gas's pressure rises as its volume shrinks, at constant temperature?

Robert Boyle published the law in 1662. In France the same rule is often called Mariotte's law, after the physicist Edme Mariotte.

Which property of carbon-14, a span of roughly 5,700 years, lets scientists date ancient remains?

Half-life is the time a radioactive sample takes to shrink to 50% of its starting amount. The term began as 'half-life period' in 1907 and was shortened in the early 1950s.

Which Danish physicist's model of the atom put electrons in orbits with fixed, quantized energies?

Niels Bohr was also a keen footballer who kept goal for a Copenhagen club, while his brother played for Denmark at the 1908 Olympics. The synthetic element bohrium is named after him.

Which element, top of the halogen group, has the highest electronegativity of any reactive one?

Fluorine is so reactive that it attacks almost every other element. Tamed as fluoride, it goes into toothpaste, where it helps to prevent dental cavities.

In DNA, which base pairs with adenine, a job that uracil takes over in RNA?

Thymine and adenine form the A–T pair that helps hold the two strands together. Chemically it is uracil with one methyl group added, hence its other name, 5-methyluracil.

Which German meteorologist proposed in 1912 that the continents are slowly drifting?

Alfred Wegener was known in his lifetime mainly as a polar researcher who joined several Greenland expeditions. Mainstream geology did not accept his drifting continents until the 1960s.

Which layer, made mostly of liquid iron and nickel, generates Earth's magnetic field?

The outer core stays liquid because the pressure there is too low to make it solid. Scientists know it is fluid because seismic shear waves cannot travel through it.

In an experiment, which type of variable does the experimenter deliberately change?

The independent variable is the one the experimenter manipulates. The dependent variable is the outcome that is expected to change in response.

Which process, joining light nuclei into heavier ones, powers the Sun and other stars?

Nuclear fusion in stars was predicted by Arthur Eddington in 1920. The clue was a weighing: four of the lightest atoms turned out to be heavier than the one helium atom they can form.

Which gas forms a layer in the stratosphere that absorbs most of the Sun's ultraviolet radiation?

The ozone layer absorbs 97 to 99 percent of the Sun's mid-range ultraviolet light. Industrial chemicals called CFCs were found to be thinning it, so the 1987 Montreal Protocol phased them out.

Which French chemist's principle predicts how a chemical equilibrium shifts when conditions change?

Henry Le Chatelier stated it in 1884. It explains a trade-off in making ammonia: a lower temperature gives more product but slows the reaction, so industry runs at a compromise.

Which German astronomer, once assistant to Tycho Brahe, showed that planets orbit in ellipses?

Johannes Kepler made about 40 failed attempts on the orbit of Mars before he tried an ellipse, a shape he had assumed was too simple for earlier astronomers to have overlooked.