100 Science Trivia Questions and Answers
Explore 100 science questions with clear answers, from atoms and energy to living things, Earth and space. Use the cards for a quick quiz, then browse the full list at your own pace.
All 100 Science Questions and Answers
Work through the complete set below. Each question focuses on a stable scientific fact rather than current news or a school-specific syllabus.
What is the speed of light in a vacuum?#1Show Answer
Exactly 299,792,458 metres per second.
How is a molecule of water written as a chemical formula?#2Show Answer
H₂O.
What is the atomic number of carbon?#3Show Answer
6.
What pH is neutral water at about room temperature?#4Show Answer
pH 7.
Which gas makes up most of Earth's atmosphere?#5Show Answer
Nitrogen, at about 78 percent.
What is the SI unit of electric current?#6Show Answer
The ampere.
What is the SI unit of force?#7Show Answer
The newton.
What is the everyday name for sodium chloride?#8Show Answer
Table salt.
Which element has the chemical symbol Au?#9Show Answer
Gold.
What electrical charge does an electron carry?#10Show Answer
A negative charge.
Which two particles are found in the nucleus of most atoms?#11Show Answer
Protons and neutrons.
Which element has one proton in each atom?#12Show Answer
Hydrogen.
What is the smallest unit of an element that retains that element's chemical properties?#13Show Answer
An atom.
What is the change from a liquid to a gas called?#14Show Answer
Vaporisation.
What is it called when a solid changes directly into a gas?#15Show Answer
Sublimation.
What does a catalyst do in a chemical reaction?#16Show Answer
It increases the reaction rate without being consumed overall.
How is density calculated?#17Show Answer
Mass divided by volume.
Can sound travel through a perfect vacuum?#18Show Answer
No. Sound needs a material medium.
What process separates white light into a spectrum of colours?#19Show Answer
Dispersion.
What does a convex lens do to parallel rays of light?#20Show Answer
It brings them together, or converges them.
Which unit measures frequency?#21Show Answer
The hertz.
What is Earth's gravitational acceleration near sea level, to one decimal place?#22Show Answer
About 9.8 metres per second squared.
Which simple machine is a ramp?#23Show Answer
An inclined plane.
What kind of energy does a raised object have because of its position?#24Show Answer
Gravitational potential energy.
Which kind of heat transfer can travel through empty space?#25Show Answer
Radiation.
At standard atmospheric pressure, at what temperature does pure water boil?#26Show Answer
100 °C.
At standard atmospheric pressure, at what temperature does pure water freeze?#27Show Answer
0 °C.
Why are many metals good electrical conductors?#28Show Answer
They contain electrons that can move freely through the material.
What happens when two like magnetic poles are brought together?#29Show Answer
They repel each other.
What is the name for a complete path through which electric current can flow?#30Show Answer
An electric circuit.
What theory explains the movement of Earth's large crustal plates?#31Show Answer
Plate tectonics.
Which instrument records ground motion during an earthquake?#32Show Answer
A seismometer.
What is molten rock called while it is below Earth's surface?#33Show Answer
Magma.
What is molten rock called after it reaches Earth's surface?#34Show Answer
Lava.
Which is Earth's largest ocean?#35Show Answer
The Pacific Ocean.
Which trench contains the deepest known point in the ocean?#36Show Answer
The Mariana Trench.
What is the hardest mineral on the Mohs scale?#37Show Answer
Diamond.
What type of rock forms when magma or lava cools and solidifies?#38Show Answer
Igneous rock.
What type of rock commonly forms from compacted and cemented sediments?#39Show Answer
Sedimentary rock.
What type of rock forms when existing rock is changed by heat and pressure?#40Show Answer
Metamorphic rock.
What is the process by which liquid water becomes water vapour?#41Show Answer
Evaporation.
What process forms cloud droplets from water vapour?#42Show Answer
Condensation.
Which atmospheric layer contains most of the ozone that absorbs ultraviolet radiation?#43Show Answer
The stratosphere.
What is the difference between weather and climate?#44Show Answer
Weather describes short-term conditions; climate describes long-term patterns.
Which celestial body has the greatest effect on Earth's ocean tides?#45Show Answer
The Moon.
What is an equinox?#46Show Answer
A time when day and night are approximately equal in length worldwide.
What is the main reason Earth has seasons?#47Show Answer
Earth's axis is tilted as the planet orbits the Sun.
In which layer of the atmosphere does most weather occur?#48Show Answer
The troposphere.
Which two elements make up most of Earth's core?#49Show Answer
Iron and nickel.
What is Earth's only natural satellite?#50Show Answer
The Moon.
What type of celestial object is the Sun?#51Show Answer
A star.
Name the planet that orbits nearest to the Sun.#52Show Answer
Mercury.
Which is the largest planet in the Solar System?#53Show Answer
Jupiter.
Why does Mars look reddish?#54Show Answer
Iron oxides in its surface material give it a reddish colour.
Which planet is especially known for its bright ring system?#55Show Answer
Saturn.
What is the name of the galaxy that contains our Solar System?#56Show Answer
The Milky Way.
Does a light-year measure time or distance?#57Show Answer
Distance.
What causes the phases of the Moon?#58Show Answer
We see different portions of the Moon's sunlit half as it orbits Earth.
What happens during a solar eclipse?#59Show Answer
The Moon passes between Earth and the Sun and blocks some or all of the Sun from view.
How strong is gravity on the Moon compared with Earth?#60Show Answer
About one-sixth as strong.
In which plant organelle does photosynthesis take place?#61Show Answer
The chloroplast.
Which green pigment absorbs light for photosynthesis?#62Show Answer
Chlorophyll.
Which cell organelle produces most usable energy through cellular respiration?#63Show Answer
The mitochondrion.
What is the familiar shape of a DNA molecule?#64Show Answer
A double helix.
How many pairs of chromosomes do most human body cells contain?#65Show Answer
23 pairs.
Which organ pumps blood around the human body?#66Show Answer
The heart.
Which organ covers the body and has the greatest total area?#67Show Answer
The skin.
Where in the lungs does most gas exchange take place?#68Show Answer
In the alveoli.
Which protein in red blood cells carries oxygen?#69Show Answer
Haemoglobin.
Where does the digestion of starch begin?#70Show Answer
In the mouth.
Which organ produces insulin?#71Show Answer
The pancreas.
Which organs filter the blood and produce urine?#72Show Answer
The kidneys.
What is the specialised cell that carries signals in the nervous system?#73Show Answer
A neuron, or nerve cell.
What is the longest bone in the adult human body?#74Show Answer
The femur.
How many teeth does a typical adult have when all wisdom teeth are present?#75Show Answer
32.
What is the average core body temperature often used as a reference for healthy adults?#76Show Answer
About 37 °C.
Which gas do plants take in for photosynthesis?#77Show Answer
Carbon dioxide.
Which plant tissue carries water upward from the roots?#78Show Answer
Xylem.
What is pollination?#79Show Answer
The transfer of pollen from an anther to a stigma.
What are the first seed leaves of an embryo plant called?#80Show Answer
Cotyledons.
What do female mammals produce to feed their young?#81Show Answer
Milk from mammary glands.
How many legs does an adult insect have?#82Show Answer
Six.
How many legs does an arachnid such as a spider have?#83Show Answer
Eight.
Is a frog a reptile or an amphibian?#84Show Answer
An amphibian.
Is a whale a fish or a mammal?#85Show Answer
A mammal.
What is the largest animal known to live on Earth?#86Show Answer
The blue whale.
Which mammals are capable of sustained powered flight?#87Show Answer
Bats.
Which body covering is unique to birds?#88Show Answer
Feathers.
What do ecologists call organisms that make their own food and begin most food chains?#89Show Answer
Producers.
Are fungi classified as plants?#90Show Answer
No. Fungi form their own biological kingdom.
Do bacterial cells have a membrane-bound nucleus?#91Show Answer
No.
What do viruses need in order to reproduce?#92Show Answer
Living host cells.
What process favours inherited traits that improve survival and reproduction?#93Show Answer
Natural selection.
What does an ecosystem include?#94Show Answer
A community of organisms and the non-living environment they interact with.
What role do decomposers play in an ecosystem?#95Show Answer
They break down dead material and return nutrients to the environment.
Why does an experiment use a control group?#96Show Answer
To provide a baseline for comparison.
What is an independent variable?#97Show Answer
The factor deliberately changed by the experimenter.
Why are repeated trials useful in an experiment?#98Show Answer
They help reveal variation and make the result more reliable.
What makes a scientific hypothesis useful?#99Show Answer
It must be testable and capable of being supported or rejected by evidence.
How many base units are defined in the SI system?#100Show Answer
Seven.
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