Many science "facts" we learned as kids turn out to be myths, while some real science sounds too odd to be true. This science myths true or false quiz covers memory, lightning, light, sound, diamonds and the human body. Decide whether each statement holds up, then read the quick explanation to see what researchers have actually found. It's a fun way to clear out a few old misconceptions.
Science myths spread for understandable reasons. Many start as a simplification that a teacher, cartoon or advertisement used to make an idea easier, and the simple version outlives the real one. Others begin with a real observation that gets stretched too far. Once a catchy claim is repeated often enough, it starts to feel like common knowledge, and people rarely stop to check something everyone seems to agree on.
Scientists have a useful habit worth borrowing: ask how anyone could know. If a claim is true, someone should have been able to measure it, test it or watch it happen. Myths often fall apart when you picture the experiment. Another tip is to watch for claims that sound too tidy, since nature tends to be messier than a slogan. On the other hand, the real universe is full of facts that sound invented, so strangeness alone is not proof a statement is false.
This quiz pairs familiar myths with surprising truths from physics, astronomy, chemistry, geology and biology. The explanations are short, so you can pick up the real story behind each one and pass it along the next time an old myth comes up in conversation.
Goldfish have a memory span of only about three seconds.
Answer: False
Experiments show goldfish can remember things for months and can even be trained to respond to sounds or press levers for food.
Sound travels faster through water than through air.
Answer: True
Sound moves about four times faster in water, roughly 3,300 mph (1,480 m/s) versus about 767 mph (343 m/s) in air.
Lightning never strikes the same place twice.
Answer: False
Tall structures get hit again and again. The Empire State Building is struck an average of about 23 times a year.
Earth is closest to the sun in early January.
Answer: True
Seasons come from the tilt of Earth's axis, not distance, so the Northern Hemisphere has winter when Earth is nearest the sun.
Most people use only about 10% of their brains.
Answer: False
Brain scans show activity throughout the brain, and nearly every region has a known job.
Bananas are very slightly radioactive.
Answer: True
They contain potassium, including a tiny amount of radioactive potassium-40, far too little to cause any harm.
The blood in your veins is blue until it touches oxygen.
Answer: False
Human blood is always red. Blood low in oxygen is a darker red, and veins only look blue through skin.
Perfectly pure water is a poor conductor of electricity.
Answer: True
Dissolved minerals and salts, which form ions, are what let everyday water carry an electric current.
Most diamonds form when coal is squeezed under high pressure.
Answer: False
Most diamonds form from carbon deep in Earth's mantle, about 90 to 155 miles (150 to 250 km) down, and are far older than coal.
Light from the sun takes about eight minutes to reach Earth.
Answer: True
The trip across roughly 93 million miles (150 million km) takes about 8 minutes and 20 seconds.