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ScienceEasy

True or False: Science

The Mpemba effect (hot water freezing before cold) exists, the Sun isn't burning but undergoing nuclear fusion, a teaspoon of neutron star weighs 6 billion tons. 20 counter-intuitive claims to sort as TRUE or FALSE.

20

Questions

2

Minutes

Tip: Use keys 1-4 to answer quickly

The 20 quiz questions

Question 1 : Hot water can freeze faster than cold water under certain conditions.

Possible answers:

  • True
  • False

Explanation: TRUE! This is the Mpemba effect. Under certain conditions, hot water freezes faster than cold water. This counterintuitive phenomenon is still being studied by scientists.

Question 2 : The Sun is a ball of fire.

Possible answers:

  • True
  • False

Explanation: FALSE! The Sun is not on fire. It is an enormous ball of gas where nuclear fusion reactions occur. Fire requires oxygen, which is absent in space.

Question 3 : A teaspoon of neutron star would weigh about 6 billion tons.

Possible answers:

  • True
  • False

Explanation: TRUE! Neutron stars are incredibly dense. Matter is so compressed there that a small amount would weigh billions of tons on Earth.

Question 4 : Sound cannot travel through space.

Possible answers:

  • True
  • False

Explanation: TRUE! Space is a near-perfect vacuum. Without molecules to transmit vibrations, sound cannot travel. In space, no one can hear you scream!

Question 5 : Electrons orbit the atomic nucleus like planets around the Sun.

Possible answers:

  • True
  • False

Explanation: FALSE! This is a simplified but incorrect representation. In quantum mechanics, electrons exist in "probability clouds" around the nucleus, not in defined orbits.

Question 6 : A cloud can weigh several million tons.

Possible answers:

  • True
  • False

Explanation: TRUE! An average cumulus cloud contains about 500,000 kg of water. Large storm clouds can contain millions of tons of water suspended as droplets.

Question 7 : Diamonds are indestructible.

Possible answers:

  • True
  • False

Explanation: FALSE! Diamonds are very hard but not indestructible. They can be burned at high temperatures (about 850°C) and fractured by a violent impact. Hardness does not equal resistance!

Question 8 : Sunlight takes about 8 minutes to reach Earth.

Possible answers:

  • True
  • False

Explanation: TRUE! The Sun is about 150 million km from Earth. Light travels at 300,000 km/s, so it takes about 8 minutes and 20 seconds to reach us.

Question 9 : Oxygen is the most abundant gas in the air we breathe.

Possible answers:

  • True
  • False

Explanation: FALSE! Nitrogen makes up about 78% of Earth's atmosphere. Oxygen only makes up 21%. The rest is composed of argon, CO2 and other gases.

Question 10 : The human body contains enough iron to make a small nail.

Possible answers:

  • True
  • False

Explanation: TRUE! The human body contains about 3 to 4 grams of iron, mainly in the hemoglobin of blood. This is enough to make a 7-8 cm nail.

Question 11 : Plants only breathe during the day.

Possible answers:

  • True
  • False

Explanation: FALSE! Plants breathe 24/7. Photosynthesis (which produces oxygen) only happens during the day, but cellular respiration (which consumes oxygen) is continuous.

Question 12 : The DNA of all humans is 99.9% identical.

Possible answers:

  • True
  • False

Explanation: TRUE! Genetically, all humans share 99.9% of their DNA. The remaining 0.1% explains all our physical differences and certain predispositions.

Question 13 : Black holes are holes in space.

Possible answers:

  • True
  • False

Explanation: FALSE! A black hole is not a "hole" but an extremely dense celestial object whose gravity is so strong that nothing, not even light, can escape from it.

Question 14 : The temperature at the center of the Sun reaches about 15 million degrees Celsius.

Possible answers:

  • True
  • False

Explanation: TRUE! At the core of the Sun, the temperature reaches about 15 million degrees. This extreme heat enables the nuclear fusion of hydrogen into helium.

Question 15 : Koala fingerprints are almost identical to human fingerprints.

Possible answers:

  • True
  • False

Explanation: TRUE! Koalas have fingerprints so similar to ours that they could theoretically contaminate a crime scene. Even experts have difficulty telling them apart!

Question 16 : Pure water is an excellent conductor of electricity.

Possible answers:

  • True
  • False

Explanation: FALSE! Pure (distilled) water is a very poor conductor. It is the dissolved minerals and impurities in water that make it conductive. Tap water conducts electricity, pure water does not.

Question 17 : It rains diamonds on Neptune and Uranus.

Possible answers:

  • True
  • False

Explanation: TRUE! On Neptune and Uranus, atmospheric methane decomposes under high pressure into hydrogen and carbon, the latter forming diamond crystals that fall towards the core. Confirmed in laboratory in 2017 (SLAC, Stanford).

Question 18 : Atoms are the smallest particles of matter that exist.

Possible answers:

  • True
  • False

Explanation: FALSE! Atoms are made up of even smaller particles: protons, neutrons and electrons. And protons and neutrons are themselves made up of quarks!

Question 19 : Your body produces about 25 million new cells every second.

Possible answers:

  • True
  • False

Explanation: TRUE! The human body is an incredible factory. Every second, millions of cells die and are replaced by new ones, ensuring the constant renewal of our tissues.

Question 20 : Gravity is the most powerful force in the universe.

Possible answers:

  • True
  • False

Explanation: FALSE! Gravity is actually the weakest of the four fundamental forces! The strong nuclear force is about 10^38 times more powerful. But gravity acts over large distances.

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