Brain Facts

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Test your knowledge about the human brain and how it works!

15 quick questionsNo sign-upFree to playTap an answer below to begin ↓

Approximately how much does the average adult human brain weigh?

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About Brain Facts

Give your memory a workout with Brain Facts: 15 multiple-choice questions with a mix of 5 easy, 5 medium, 5 hard questions, free to play right in your browser. Test your knowledge about the human brain and how it works! Expect to spend about 7 minutes; every question comes with an explanation, so you learn something even when you miss.

A few sample questions

  1. 1. Approximately how much does the average adult human brain weigh?

    Answer: 3 pounds

    The average adult human brain weighs about 3 pounds (1.4 kilograms). Despite being only about 2% of body weight, it uses about 20% of the body's energy.

  2. 2. What percentage of the brain is made up of water?

    Answer: About 73%

    The brain is about 73% water. Even mild dehydration (just 2%) can affect attention, memory, and other cognitive skills.

  3. 3. What is the largest part of the human brain called?

    Answer: Cerebrum

    The cerebrum is the largest part of the brain, making up about 85% of its total weight. It is responsible for thinking, learning, memory, and voluntary movements.

  4. 4. How many main lobes does each hemisphere of the brain have?

    Answer: 4

    Each hemisphere has 4 main lobes: frontal (reasoning, planning), parietal (sensory processing), temporal (hearing, memory), and occipital (vision).

  5. 5. What are the cells in the brain that transmit information called?

    Answer: Neurons

    Neurons are the brain's information-transmitting cells. The human brain contains approximately 86 billion neurons, each connected to thousands of others.

Things you'll learn along the way

  • The cerebellum, located at the back of the brain, controls balance, coordination, and fine motor skills. It contains about 50% of the brain's neurons despite being only 10% of its volume.
  • Neuroplasticity is the brain's remarkable ability to reorganize itself by forming new neural connections throughout life. This ability is crucial for learning, memory, and recovery from brain injuries.
  • Information can travel along neurons at speeds up to 268 mph (431 km/h). The speed varies depending on the type of neuron and whether it has a myelin sheath.

Frequently asked questions

How long does Brain Facts take?

Most players finish Brain Facts in about 7 minutes. You can pause between questions, replay it as often as you like, and there is no penalty for taking your time — answers are explained after you submit them.

What's a good follow-up after Brain Facts?

If you enjoyed this memory games quiz, try the Daily Challenge — five rotating questions, refreshed every 24 hours, that count toward your streak. You can also use the Surprise Me button on the homepage to land on a different game type for variety.

Can I print Brain Facts?

Yes — use the Print button at the top of the page for a clean question sheet, or "Print with Answers" to make an answer key. Printed sheets work well for group play at home, in a classroom, or at a senior center.

Will I lose my progress if I close the page?

Your overall progress — XP, streaks, and badges — is saved in your browser automatically. A quiz that's underway restarts if you leave mid-game, but at about 7 minutes, Brain Facts fits comfortably in one sitting.

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