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Simple science questions about planets, nature and the human body.
1. What is H2O?
💡 H2O is the chemical formula for water. It means each water molecule has 2 hydrogen atoms and 1 oxygen atom bonded together. Water covers about 71% of Earth's surface.
2. What is the closest planet to the Sun?
💡 Mercury is the closest planet to the Sun. Despite being closest, it is not the hottest — that is Venus, because Venus has a thick atmosphere that traps heat.
3. What is the hottest planet in our solar system?
💡 Venus is the hottest planet with surface temperatures reaching 465°C (870°F). Its thick atmosphere of carbon dioxide creates a powerful greenhouse effect that traps heat.
4. What gas do humans need to breathe to survive?
💡 Humans need oxygen to survive. We breathe in air (which is 21% oxygen) and our lungs extract the oxygen for our blood to carry to all parts of the body.
5. How many colors are in a rainbow?
💡 A rainbow has 7 colors: Red, Orange, Yellow, Green, Blue, Indigo, and Violet. You can remember them with the name ROY G BIV. Rainbows form when sunlight passes through water droplets.
6. What is the biggest planet in our solar system?
💡 Jupiter is the biggest planet in our solar system — so large that all other planets could fit inside it with room to spare! It is also famous for its Great Red Spot, a storm that has raged for hundreds of years.
7. What do plants need to make their own food?
💡 Plants make food through photosynthesis using sunlight, water (from roots), and carbon dioxide (from air). They produce glucose for energy and release oxygen as a byproduct.
8. What is the name of our galaxy?
💡 We live in the Milky Way galaxy. It contains over 200 billion stars and is about 100,000 light-years across. On a clear dark night, you can see part of it as a faint band across the sky.
9. How many planets are in our solar system?
💡 Our solar system has 8 planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Pluto was reclassified as a dwarf planet in 2006.
10. Which planet is known as the Red Planet?
💡 Mars is called the Red Planet because of iron oxide (rust) on its surface that gives it a reddish appearance. Mars has the tallest volcano in the solar system — Olympus Mons at 22 km high.