Water has been a hot topic in South Africa lately: Cape Town's drought, ways to save water, and whether or not President Ramaphosa and Trevor Manuel had a two-minute shower after their jog (and listened to the advice of Ayoba the penguin). We challenged you to take part in a quiz to see how much you really knew about "water".

Congratulations to Amina and Kirstin for really knowing everything about good old H₂O and each winning a pair of Two Oceans Aquarium tickets and a pair of reusable bamboo straws from the We Care Collective!

If you would like to try the quiz yourself before looking at the answers, you can try it here. In the meantime, here is a distracting video to keep you from cheating at scrolling down to the answers:

1. We asked: What percentage of the Earth's surface is covered in liquid water?

Answer: 71% (87% of you got this right)

Earth is almost completely covered in water – there’s a reason it is called the blue planet. Perhaps this photo of the Earth will put in perspective just how little land there is when we don’t point our cameras directly at it.

2. We asked: How much does 1 litre of water weigh?

Answer: 1 kilogram (90% of you got this right)

A litre of pure water weighs almost exactly one kilogram because when the metric system was originally conceptualized, it was actually used to define what a “kilogram” was. 

3 We asked: How much of your brain is made out of water?

Answer: 70% (84% of you got this right)

Your brain is made of 70-73% water – so when it’s been a long day and it feels like mush, that’s because it actually is mushy. This is why substances like alcohol can induce headaches – they dehydrate your brain.

4. We asked: How many litres of municipal water can people in Cape Town use per day (as of 21 Feb)?

Answer: 50 litres (93% of you got this right)

5. We asked: For how long can a human survive without drinking water?

Answer: 2 to 7 days (85% of you got this right)

6. We asked: What is water made out of?

Answer: One part oxygen, two parts hydrogen (84% of you got this right)

The chemical formula for water, H₂O, is an exact recipe for water. H₂ = 2x hydrogen, O = 1x oxygen.

Bonus nerd fact: NO₂ is nitrogen dioxide, a bad atmospheric pollutant. HO₂ is hydroperoxyl, a “superoxide” that destroys many pollutants in the upper atmosphere. H₂O₂ is hydrogen peroxide, the chemical that angsty teenagers use to get ridiculous hairstyles. 

7. We asked: How much water is on Earth?

Answer: One and a half sextillion litres (1 500 000 000 000 000 000 000L) (59% of you got this right)

We know what you’re thinking – that’s an unbelievably huge number. Here’s some context – A sextillion people standing in a line would be enough to stretch right across the Milky Way galaxy… and back!

While that number is huge, the actual amount of water that is fresh is less than 2.5% of that – and only 0.3% of that 2.5% is on the surface! We need to treasure that small fraction.

8. We asked: What is the "real" name for water, recognized by the IUPAC?

Answer: Oxidane (35% of you got this right - 53% voted Aqua Regia, which is a very potent acid)

The International Union of Pure and Applied Chemistry lay out rules for the naming of chemicals and molecules – “oxidane” being the correct nomenclature for water. Famous spoofs often give water scientific sounding names like “dihydrogen monoxide”, but none of these are correct.

Bonus nerd fact: If you walk into a laboratory and ask for a glass of oxidane, you will only get funny looks, but no water.

9. We asked: Which substance is the worst conductor of electricity?

Answer: Distilled water (44% of you got this right)

Electricity is not conducted by water, it is carried by dissolved ions that move through the water. Water with lots of impurities (even those intentionally added to tap and bottled water) is good at conducting electricity, whereas 100% pure water is a very poor conductor.

Bonus nerd fact: Despite common belief, 100% pure water CAN conduct electricity, because water’s H₂O can split up into hydroxide (OH-) and hydronium (H₃O+) ions if needed. It just doesn’t do this very efficiently.

10. We asked: Which of these is a way that your body loses almost a cup of water a day?

Answer: Breathing it out (81% of you got this right)

Competition terms and conditions

1. All content sent to the Two Oceans Aquarium as entry into the competition may be used on the Aquarium’s website and associated digital platforms.
2. Entries close at 24h00 on Wednesday 21 March 2018.
3. Winners will be notified on Thursday 22 March 2018.
4. To be entered into the lucky draw, all 10 questions must be answered correctly.
5. Two individual winners will be chosen by lucky draw.
6. Each winner will receive two complimentary day tickets to the Two Oceans Aquarium and two bamboo straws from the We Care Collective. Tickets will be available at the Aquarium's front desk and are valid for 3 months from the date that winners have been notified.
7. Representatives of the Two Oceans Aquarium will pick the winner from eligible entries.
8. Prizes are non-transferable.
9. Prizes must be redeemed within three months of date of issue.
10. The judges’ decision is final and no correspondence will be entered into.
11. The winners may be required to participate in a photo-taking session during the issuing of the prize.
12. Pictures may be posted online.
13. Entry into the competition and acceptance of any prize shall constitute consent on the winner's part to allow the use of the winner's name, image, voice and/or likeness by the Two Oceans Aquarium for editorial, advertising, promotional, marketing and/or other purposes without further compensation except where prohibited by law.
14. This competition is not open to Two Oceans Aquarium or We Care Collective staff or volunteers and their families.
15. Anyone who has won a competition or promotion through the Two Oceans Aquarium in the last six months is not eligible to win.