Bones and Muscles
Imagine trying to stand up, walk, or even smile without any bones or muscles. You would just be a floppy puddle on the floor! Join Bill Nye the Science Guy as we look inside our bodies to see how these two vital systems work perfectly together.
What Keeps You From Becoming a Puddle?
Around 206 bones! While babies are born with many more, those smaller bones fuse together as they grow, leaving adults with a strong framework of 206 individual bones.
They only pull! As Bill Nye the Science Guy demonstrates, muscles work by contracting and getting shorter. They can never push a bone, which is why muscles always work in pairs to pull bones back and forth.
Put Your Instincts to the Test
Think about what you already know about your own body. Pick an answer for each question, then see if your instincts were right.
Inside your ear! The smallest bones in your body are located deep inside your ear. They are incredibly tiny but are vital for helping you hear sounds.
An exoskeleton! Insects and crabs have hard, protective outer shells that act exactly like a skeleton on the outside of their bodies.
Cartilage! This smooth, rubbery tissue is found at the ends of your bones. It keeps your joints sliding smoothly so your bones do not painfully grind together.
Understanding the Science
Tap each card to uncover the biological engineering that allows you to run, jump, and lift.
Key Concepts
Bones
Tap to learn moreThese are the rigid, living structures that give your body its shape, support your weight, and protect your fragile internal organs.
Muscles
Tap to learn moreThese are tissues that contract and relax to move your bones. Remember the golden rule of biology: muscles only pull, they never push!
Joints
Tap to learn moreThese are the special places where two or more bones meet, allowing your rigid skeleton to bend, twist, and pivot.
Cartilage
Tap to learn moreA smooth, rubbery tissue found at the ends of bones. It acts as a shock absorber so your bones do not painfully grind together.
Ligaments
Tap to learn moreStrong, flexible bands of tissue that connect one bone directly to another bone, keeping your joints stable and secure.
Tendons
Tap to learn moreTough, elastic cords that attach your pulling muscles directly to your bones, allowing the muscle to haul the bone upwards.
Vertebrae
Tap to learn moreThe 33 individual bones stacked on top of each other that make up your spine, protecting your delicate spinal cord.
Exoskeleton
Tap to learn moreA hard, protective outer shell found on insects and crabs, acting exactly like a skeleton on the outside of their bodies.
Try It: The Heavy Lift
Muscles only pull, they never push! To bend your arm, your bicep must contract while your triceps relaxes.
The Mission: Use the slider to command the bionic arm to lift the heavy weight. Turn your sound up to hear the bionic muscle straining under the pressure!
Apply Your Knowledge
Let us see if you can connect these vital tissues to their jobs in your body.
Match the Concepts
Click a tissue to select it, then click the matching description to place it.
Real-World Challenge
Birds can fly gracefully, but humans cannot. Thinking about the structure of a bird's skeleton compared to a human's skeleton, what special adaptation do birds have in their bones that makes them light enough to take to the skies?
What Has Changed Since This Episode Aired
This episode aired in 1994. While the core rules of biology remain completely accurate, our understanding of the human body and medical technology has expanded rapidly.
Updated: Yes! Today, advanced imaging allows us to know with precision that babies are born with about 300 distinct bones! As they grow into teenagers, many of these smaller sections (especially in the skull and the spine) permanently fuse together to form the 206 solid bones adults rely on.
Updated: Modern bionics have advanced incredibly since 1994! Today, biomedical engineers have created robotic limbs that can actually connect directly to a person's nervous system, allowing them to control the robotic fingers using just their thoughts, almost exactly like a natural limb.
Test Your Understanding
Answer these questions and get instant feedback. How many can you get right?
Results
Your score:
Reflection
Think about the actions you perform every single day, like chewing your food or blinking your eyes. Can you guess which muscles in your head and face are pulling to make those movements happen?
Episode Discussion
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