Human Body Facts for Kids
Surprising facts about your body
Your brain generates about 12-25 watts of electricity while you're awake — enough to power a small LED light bulb. This electrical activity comes from the billions of neurons constantly sending signals to each other. Scientists can measure these brain waves with a machine called an EEG.
Scientists believe the human nose can detect up to one trillion different scents. Smell is the most ancient of all our senses and is directly connected to the brain's emotional and memory centers. This is why a smell can instantly trigger a powerful memory from years ago.
Humans are the only animals on Earth with a true chin — a bony protrusion at the bottom of the jaw that serves no obvious functional purpose. All other animals, including our closest relatives chimpanzees, have flat or receding jaws. Scientists are still debating why humans evolved this distinctive feature.
Earwax might seem gross, but it plays an important role in protecting your ear canal. It traps dust, bacteria, and small insects before they can reach the eardrum, and it contains chemicals that fight infection. Your ears are actually self-cleaning — the wax gradually moves to the outer ear on its own.
If you stretched out all of the blood vessels in an adult human body — arteries, veins, and tiny capillaries — they would extend about 60,000 miles. That's long enough to circle the Earth more than twice. The smallest capillaries are so thin that red blood cells must travel through them in single file.
A sneeze can send droplets flying at speeds of up to 100 miles per hour. The spray from a sneeze can travel up to 27 feet through the air, much farther than scientists previously thought. This is why covering sneezes is so important for preventing the spread of illness.
In complete darkness, the human eye can detect a single candle flame from as far as 14 miles away. The eye's rod cells, which detect light in dim conditions, are incredibly sensitive. After about 30 minutes in the dark, your eyes become up to 100,000 times more sensitive to light than in bright conditions.
Pound for pound, human bone is stronger than solid steel. A cubic inch of bone can withstand forces of up to 19,000 pounds. Bone is also slightly flexible, which prevents it from shattering on impact the way a completely rigid material would.
Just like your fingerprints, your tongue print is completely unique to you. No two people have the same pattern of bumps and ridges on their tongue. Scientists have even explored using tongue prints as a form of biometric identification in security systems.
Your skeleton is constantly being broken down and rebuilt in a process called bone remodeling. Old bone tissue is absorbed by the body and replaced with new bone cells. Over about 10 years, your skeleton has essentially been completely replaced, though the process slows as you age.