1. What is the chemical formula for water?
H2O
Each water molecule is two hydrogen atoms joined to one oxygen atom.
2. Which planet is closest to the Sun?
Mercury
Mercury whips around the Sun in just 88 Earth days.
3. Which planet is known as the Red Planet?
Mars
Mars looks red because its surface is covered in rusty iron oxide dust.
4. Which is the largest planet in our solar system?
Jupiter
Jupiter is so big that more than 1,300 Earths could fit inside it.
5. Which gas do plants take in for photosynthesis?
Carbon dioxide
Plants use carbon dioxide, water and sunlight to make their food.
6. Which gas do plants release during photosynthesis?
Oxygen
The oxygen we breathe mostly comes from plants and ocean algae.
7. Which gas makes up most of Earth's atmosphere?
Nitrogen
The air is about 78 percent nitrogen and only 21 percent oxygen.
8. What force pulls objects towards the centre of the Earth?
Gravity
Gravity is why dropped things fall and why the Moon stays in orbit.
9. What is the centre of an atom called?
The nucleus
The nucleus holds the protons and neutrons, with electrons whizzing around it.
10. What electric charge does an electron have?
Negative
Electrons are negative, protons are positive, neutrons are neutral.
11. Which element has the chemical symbol O?
Oxygen
O for oxygen, the gas your body needs every second.
12. Which element has the chemical symbol Fe?
Iron
Fe comes from ferrum, the Latin word for iron.
13. Which element has the chemical symbol Au?
Gold
Au comes from aurum, the Latin word for gold.
14. At sea level, water boils at what temperature?
100 °C
Water boils at 100 degrees Celsius at sea level, lower up a mountain.
15. At what temperature does fresh water freeze?
0 °C
Zero degrees Celsius was actually defined from water's freezing point.
16. Which organ pumps blood around your body?
The heart
Your heart beats about 100,000 times every day.
17. What is the largest organ of the human body?
The skin
Skin counts as an organ, and it is by far the biggest one you have.
18. How many bones does an adult human have?
206
Babies start with around 300 bones, and many fuse together as they grow.
19. Which of these do plant cells have that animal cells do not?
A cell wall
The stiff cell wall helps plants stand up without a skeleton.
20. What does DNA stand for?
Deoxyribonucleic acid
DNA is the molecule that carries the instructions for building you.
21. What kind of object is the Sun?
A star
The Sun is an ordinary star that just happens to be very close to us.
22. About how long does the Moon take to orbit the Earth?
About a month
One trip around Earth takes the Moon about 27 days.
23. Sound travels fastest through which of these?
Solids
Particles in a solid are packed tightly, so vibrations pass along quickly.
24. Why do you see lightning before you hear the thunder?
Light travels much faster than sound
Light reaches you almost instantly, while sound takes about 3 seconds per kilometre.
25. Solar panels turn sunlight into what?
Electricity
Solar cells turn light energy straight into electrical energy.
26. What are the three common states of matter?
Solid, liquid and gas
Most everyday stuff is a solid, a liquid or a gas, and plasma makes a fourth.
27. What is it called when a liquid turns into a gas?
Evaporation
Puddles disappear on a sunny day because the water evaporates.
28. What is it called when a gas turns into a liquid?
Condensation
Water droplets on a cold window are condensation from the air.
29. An animal that eats only plants is called what?
A herbivore
Herbivores eat plants, carnivores eat meat, omnivores eat both.
30. A whale is which kind of animal?
A mammal
Whales breathe air and feed their babies milk, so they are mammals.
31. How many legs does an insect have?
6
Six legs is the insect rule; spiders have eight, so they are not insects.
32. How many legs does a spider have?
8
Eight legs makes spiders arachnids, not insects.
33. How long does Earth take to spin once on its axis?
About 24 hours
One full spin gives us one day and one night.
34. How long does Earth take to orbit the Sun?
About 365 days
One full orbit is one year, which is why a year has about 365 days.
35. On the pH scale, what does a value of 7 mean?
Neutral
Pure water sits at pH 7, right in the middle of the scale.
36. What happens when you push the north poles of two magnets together?
They push apart
Like poles repel and opposite poles attract.
37. Which of these materials conducts electricity well?
Copper
That is why electrical wires are usually made of copper.
38. Which green pigment lets plants capture light energy?
Chlorophyll
Chlorophyll is what makes leaves look green.
39. What is the scientific unit of force?
The newton
It is named after Isaac Newton, who described how forces work.
40. How does a vaccine protect you?
It teaches your immune system to recognise a germ
After a vaccine, your immune system remembers the germ and fights it fast.