60 Fun Facts About Easy Science

Which is the largest planet in the Solar System?

Its radius is about 71,000 km, and it sits 5.2 astronomical units from the Sun.

Which is the smallest planet in the Solar System, and the closest to the Sun?

It orbits between 0.31 and 0.59 astronomical units from the Sun, so its year lasts only 88 Earth days.

Roughly what share of the Solar System's total mass is the Sun?

Everything else, including all the planets, adds up to well under one percent.

The asteroid belt lies between the orbits of which two planets?

The dwarf planet Ceres, the largest object in the belt, lives there too.

Earth's atmosphere is made up mostly of oxygen and which other gas?

That gas makes up about four-fifths of the air, with oxygen just under 21%.

Which metal makes up most of Earth's core?

The core is nearly 89% of that metal, with nickel and sulfur making up most of the rest.

The red-orange colour of the surface of Mars is caused by which compound?

In other words, the planet is rusty; it is also home to two small potato-shaped moons, Phobos and Deimos.

How many natural satellites, or moons, does Mars have?

Both are small and irregular in shape, unlike Earth's large, round Moon.

What is the Sun?

It formed about 4.6 billion years ago and its diameter is roughly 109 times that of Earth.

The Sun's core produces energy by fusing hydrogen into which element?

About 600 billion kilograms of hydrogen are converted every second.

Who was the first person to walk on the Moon?

He stepped out about six hours after landing on July 20, 1969, with Aldrin following nineteen minutes later.

What was the name of the Apollo 11 lunar module that landed on the Moon?

The name came from the bird on the mission patch, while the command module that stayed in orbit was called Columbia.

How many people had walked on the Moon by the end of the Apollo programme in 1972?

Six missions landed, and the longest stays lasted up to three days.

What is the main cause of the ocean tides on Earth?

The same tidal pull has locked the Moon so that it always shows Earth the same face.

What is the chemical formula for water?

Two hydrogen atoms bonded to one oxygen atom; it is the only common substance found naturally as solid, liquid and gas on Earth.

At what temperature does water boil at sea level?

That is 212 °F; at the other end, it freezes at 0 °C (32 °F).

Roughly what fraction of Earth's surface is covered by water?

The seas and oceans hold about 96.5% of all that water.

What happens to the volume of water when it freezes into ice?

It grows by about 9%, which is why ice floats and why frozen pipes burst.

What is the green pigment that plants use to absorb light?

It reflects the green part of the spectrum rather than absorbing it, which is why most plants look green.

About how many bones does an adult human skeleton have?

Babies start with around 270, but many fuse together as we grow.

What is the largest organ of the human body?

It accounts for roughly 16% of body mass.

How many chambers does the human heart have?

Two upper atria and two lower ventricles, beating close to 72 times a minute at rest.

Roughly what percentage of an adult human body is water?

For an adult man that works out at around 42 litres.

What does DNA stand for?

Its two strands coil around each other in the famous double helix described by Watson and Crick in 1953.

How many legs does an insect have?

Three pairs of jointed legs on a three-part body; insects are the most diverse animal group, with over a million described species.

How many limbs does a spider have?

That extra pair is one reason spiders are arachnids, not insects; they spin silk from spinnerets on the abdomen.

What is the fastest land animal?

The highest reliably recorded speed is 104 km/h (65 mph), fast enough to catch antelope with a big head start.

What is the largest animal known to have ever existed?

It can reach around 30 metres in length and weigh up to 200 tonnes.

Which is the tallest living land animal?

Its neck has the same number of vertebrae as most mammals; each one is simply stretched to over 28 cm.

What is the largest living bird?

It cannot fly, but it can run at 70 km/h and lays the biggest eggs of any living land animal.

Which is the only mammal capable of true, sustained flight?

The others only glide; many of the smaller species navigate in the dark using echolocation.

What is the stage between caterpillar and adult butterfly called?

The full four-stage cycle is egg, larva, pupa (the chrysalis) and adult; monarchs then fly thousands of miles to Mexico.

Which living animals evolved from feathered dinosaurs?

They are the only dinosaur lineage to survive the extinction event about 66 million years ago.

The word 'dinosaur' comes from Greek words meaning what?

Deinos means terrible or fearfully great, and sauros means lizard or reptile.

Diamond is a crystal form of which element?

The same element as pencil graphite, arranged differently, and it is the hardest material on the Mohs scale.

What is the chemical symbol for gold?

It comes from the Latin word aurum; gold's atomic number is 79.

Which gas, lighter than air, is used to make party balloons float?

It was first spotted in sunlight during an 1868 eclipse and is named after the Greek word for the Sun.

What is the chemical symbol for oxygen?

Its atomic number is 8, and it is the most abundant element in Earth's crust.

What is the common name for sodium chloride?

Its formula is NaCl, and it works as a preservative as well as a flavour enhancer.

About how long does light from the Sun take to reach Earth?

Light travels at 299,792,458 metres per second, roughly a billion kilometres per hour.

Why can sound not travel through outer space?

Sound is a mechanical wave, so it needs air, water or a solid; it moves through steel about 17 times faster than through air.

How many colours are in the traditional rainbow?

Red, orange, yellow, green, blue, indigo and violet, remembered as Richard Of York Gave Battle In Vain.

What is the loud noise that follows a flash of lightning called?

The flash heats the air to about 30,000 °C, and the explosive expansion makes the shock wave you hear.

What is molten rock called once it flows out onto Earth's surface?

Underground it is called magma; the 79 CE eruption of Vesuvius buried Pompeii and Herculaneum.

What happens if you break a bar magnet in half?

You can never isolate a single pole; iron, nickel and cobalt are the classic metals magnets attract.

Who formulated the laws of motion and universal gravitation in the Principia of 1687?

He also built the first working reflecting telescope.

Which scientist is best known for developing the theory of relativity?

His Nobel Prize, though, was awarded in 1921 for explaining the photoelectric effect, not for relativity.

Which scientist published On the Origin of Species in 1859?

His ideas grew out of a five-year voyage on HMS Beagle, including a stop in the Galápagos Islands.

Who discovered penicillin in 1928?

The Scottish physician found it as a crude extract of a Penicillium mould growing on a dish.

Who was the first woman to win a Nobel Prize?

She remains the only person to win Nobel Prizes in two different sciences, and coined the word radioactivity.

Which scientist gave his name to the temperature scale on which water freezes at 0 degrees and boils at 100?

His original 1742 scale ran the other way, with 0 at boiling and 100 at freezing.

Which is the longest bone in the human body?

It is the only bone in the upper leg, running from the hip socket down to the knee.

Which chemical element is the lightest and most abundant in the universe?

It makes up about 75% of all normal matter, and stars such as the Sun consist mainly of it.

In 2006, which former ninth planet was reclassified as a dwarf planet?

It was discovered in 1930 by Clyde Tombaugh and has roughly one-sixth the mass of our Moon.

Which gas do plants release as a by-product of photosynthesis?

Plants store the captured light energy as sugars and starches, then burn them later through respiration.

Which planet is the second largest in the Solar System?

It is a gas giant with an average radius about nine times that of Earth, yet less than a third of Jupiter's mass.

Which planet has the hottest surface in the Solar System, at around 464 °C?

Its thick carbon-dioxide atmosphere traps heat, and the surface pressure is 92 times that of Earth at sea level.

In which of these does sound travel fastest?

Sound moves at about 343 m/s in air, roughly 1,481 m/s in fresh water and 5,120 m/s in iron.

Which iron-containing molecule gives red blood cells their red colour?

Each human red blood cell holds roughly 270 million of these molecules and circulates for about 100 to 120 days.

In a double rainbow, how do the colours of the second, outer arc appear?

The secondary arc sits about 10 degrees outside the primary one, with red on its lower edge.