The Click-Clack Club

A 3D tour of the bones for children about five to eight. The skeleton glows inside a see-through child: the skull, ribs and backbone keeping them safe, and the joints that bend and swing. Then it looks inside a thigh bone: the bone marrow making a new red blood cell, a growth plate helping the bone grow longer, and a small crack mending. Free, with no ads and no sign-ups.

What your child will learn

• Your skeleton is all your bones together. It holds you up and keeps your insides safe: the skull round the brain, the ribs round the heart and lungs, and the backbone round the spinal cord.
• A grown-up has 206 bones. A baby has about 300, and some of them join together as they grow.
• Bones are alive. Outside is hard, smooth compact bone; near the ends is lighter spongy bone; and in the middle is bone marrow, like a thick jelly, which makes red blood cells, white blood cells and platelets, every day.
• Near the ends of long bones are growth plates, made of cartilage, where new bone grows and the bone gets longer. Calcium, from milk and other foods, helps bones get hard and strong, and sunshine on the skin helps the body use it. Everyone grows at their own pace.
• Joints are where two bones meet. Knees and elbows are hinges; shoulders and hips are balls and sockets. Ligaments hold the bones together, and muscles pull on them to make them move.
• A bone can crack, but it knows how to mend: a clot, then a callus that joins it together, soft then harder, then new bone. A cast keeps it still while it heals, and children's bones mend really well.

How it works

Story. A wallaby tells it in nine short chapters (wallabies hop on big back legs, with their tail for balance). It starts with the bones a child can feel, then looks inside: a thigh bone opens, and the page turns to a close-up, the bone cut open lengthways and drawn big and simple. Each of the close-up's chapters has one ringed hero, and the chapter waits for it: a new red blood cell squeezing out of the marrow and away, a spark of calcium arriving at a growth plate as the bone grows a little longer, and a crack mending. The emu drops in for the joints, with a soft boom, as the knees bend and the hips swing. Every word is spoken and shown.

Explore. Turn the child round, peek inside (the front of the right thigh bone lifts away), or tap any bone to hear its name and what it does. Tap inside the opened bone to see the close-up. Four buttons: Bend (the knees and elbows, like hinges), Swing (the shoulders and hips, balls and sockets), Hop (like the wallaby) and Grow (a spark of calcium to a growth plate, and the child grows a little taller, then back). Follow a blood cell takes a new red blood cell from the marrow to the heart, again and again, and What's this? shows the parts one at a time, including the close-up.

Quiz. Six picture questions, read aloud, so it works before your child can read. A wrong answer greys out and they have another go; nothing is ever lost. Finishing brings a new animal for their My mob book, and a card of the words they now know.

The real words it teaches

The tour uses the real names for the parts, and says what each one means the first time. These are on the card at the end, and a tap on each says what it means. Compact bone, spongy bone, growth plates, hinge joints, balls and sockets, the clot and the callus are named in the story, and many more bones (the humerus, the radius and ulna, the kneecap, the tibia and fibula) in Explore, but kept off the card.

• Skeleton: all your bones together.
• Skull: the bones that keep your brain safe.
• Ribs: the bones round your heart and lungs.
• Backbone: 33 little bones, stacked up round your spinal cord.
• Bone marrow: the jelly inside your bones that makes blood cells.
• Joint: where two bones meet, so you can bend and move.
• Ligament: a strong band, like a rubber band, that holds your bones together.
• Femur: your thigh bone, your longest bone.

For grown-ups: the bones, in detail

The skeleton is drawn simply, and the close-up much bigger than real. What it shows, cartoon but true:

1. Compact bone (cortical bone) is dense, and built of tiny tubes of bone round channels for blood vessels and nerves. Spongy bone (cancellous or trabecular bone) is a lattice of thin struts, light but strong, and its spaces hold red marrow. The periosteum is a thin membrane round the outside, with blood vessels and nerves that feed the bone.
2. Bone marrow in children is mostly red marrow, which makes blood cells from stem cells: red cells, white cells and platelets. With age, more of it becomes yellow marrow, which is mostly fat. Bone is alive: cells called osteoblasts build new bone and osteoclasts break old bone down, so the skeleton is always being renewed.
3. Growth plates (the physes) are discs of cartilage near the ends of long bones. Cartilage cells multiply and are replaced by bone on the shaft's side, which makes the bone longer. They close, turning to bone, around the end of puberty. Calcium and phosphate harden new bone, and vitamin D, made in the skin in sunlight, helps the gut absorb calcium.
4. Joints: in the knees, elbows, shoulders and hips, the bone ends are capped with smooth cartilage and sit in a capsule of fluid. Ligaments join bone to bone; tendons join muscle to bone.
5. A broken bone (a fracture) heals in overlapping stages: a blood clot (haematoma) forms; a soft callus of cartilage and fibrous tissue bridges the gap; it hardens into bony callus over weeks; then the bone remodels back towards its old shape over months. Children's bones heal faster than adults', and remodel well.

Also left out: the tiny tubes of compact bone by name (osteons and Haversian canals), yellow marrow, cartilage on the joint surfaces, tendons, and the many smaller bones of the hands, feet and skull.

What it practises

• My body. How the body works, and the real names of its parts: the heart's atria and ventricles, arteries and veins (the Lub-Dub Club).
  AC9S1U01 (Science, Year 1); AC9HPFM03 (Health and Physical Education, Foundation)

The codes are from the Australian Curriculum v9 (Foundation to Year 1). Each links to the official wording.

Things to try together

• Find bones you can feel: a kneecap, an elbow, the ribs, a collarbone, the knobbly bumps down the back.
• Count the bones in a finger (three) and a thumb (two), by bending each bit.
• Bend an elbow: it only goes one way, like a door. Now swing an arm round at the shoulder: a ball and socket.
• Calcium comes from lots of foods: milk, cheese and yoghurt, and for families who don't eat dairy, leafy greens, calcium-set tofu and calcium-fortified plant milks. No food is good or bad.
• The sheet to print has a skeleton to label, "hinge or ball and socket?", and a string to measure an arm and a leg, then measure again in a few months.

For every child, and every body

Everyone grows at their own pace, and the tour never says anyone is too tall or too short. Moving and playing help keep bones strong "in the ways you can", so a child who uses a wheelchair, or moves differently, is included. The tour says nothing about bone conditions. The broken bone is only ever a small, clean crack, seen from inside the bone and never shown happening, with one soft tap and no pain; the words are about mending, and the cast is a helper.

• Every word is spoken and written, so it works with the sound on or off.
• It works with a keyboard: the arrow keys turn the child in Explore, and What's this? steps through the parts.
• Each hero has its own shape as well as colour: a red blood cell is a disc with a dip, calcium is a sparkle, and in the close-up white cells are lumpy balls, platelets small discs and the growth plate soft tiles.
• If your device asks for less motion, the camera cuts instead of flying, the page turns without the iris, nothing spins or wobbles, and the child crouches instead of hopping.

What's simplified, and why

• The skeleton is drawn simply: about 60 bones rather than 206 (a child has more, as some haven't joined yet). The hands and feet are a few rounded bones each, the backbone's 33 bones are drawn as 24 plus the sacrum and tailbone, and the skull is one piece with the jaw.
• Bones are drawn smooth and simple, with no bumps where the muscles join on, and the joints are drawn with small gaps so each bone shows. Ligaments and tendons aren't drawn.
• The right femur opens along its length, like a book, so its inside shows. A real bone can't open.
• The brain, heart and lungs are the hub's simple shapes, faint, so the skull and ribs have something to guard.
• The close-up is one drawing of a bone, cut open lengthways, used for the marrow, the growth plate and the mending (chapter 8's crack is in an arm bone). The honeycomb, the growth plate's tiles and the blood cells are drawn much bigger than real, and the mending, which takes weeks to months, happens in a few seconds.
• Calcium is shown as one spark going to a growth plate, and the bone growing at once. Really, calcium goes to every bone, and bones grow slowly over years; growth plates add length as calcium and other things help new bone form.
• The red blood cell's way to the heart is drawn as one vessel up the leg and body. Really, it joins the blood in many small vessels first.
• The broken bone is only ever a small, clean crack, shown from inside the bone. The tour never shows how it happened, and says nothing about pain.

Where the facts come from

Every fact the tour states was checked against the page linked beside it.

• "Every single person has a skeleton made up of many bones"; "These bones give your body structure, let you move in many ways, protect your internal organs, and more"
  In the tour: This is your skeleton: all your bones together. It holds you up! (Tap: Your skeleton: all your bones together. They hold you up and keep your insides safe.)
  KidsHealth (kids) — Your Bones
• "A baby's body has about 300 bones at birth. These eventually fuse (grow together) to form the 206 bones that adults have"
  In the tour: A grown-up has 206 bones. A baby has about 300, and some of them join together as you grow.
  KidsHealth (kids) — Your Bones
• the knee: "A triangular-shaped bone called the patella, or kneecap"; "Your elbows and knees each have hinge joints"; "you've got ribs to keep them safe"
  In the tour: Feel your knee, your elbow, your ribs. Those are bones!
  KidsHealth (kids) — Your Bones
• "Your skull protects the most important part of all, the brain"
  In the tour: Your skull keeps your brain safe, like a helmet.
  KidsHealth (kids) — Your Bones
• "Your heart, lungs, and liver are all very important, and luckily you've got ribs to keep them safe"; "Most people have 12 pairs of ribs"
  In the tour: Your ribs are like a cage round your heart and lungs. (Tap: 12 pairs of them.)
  KidsHealth (kids) — Your Bones
• the spine: "It's made of 33 bones in all! These bones are called vertebrae"; "The spine lets you twist and bend"
  In the tour: Your backbone: 33 little bones, stacked up. (Tap: called vertebrae. It lets you twist and bend.)
  KidsHealth (kids) — Your Bones
• the spine "also protects the spinal cord, a large bundle of nerves that sends information from your brain to the rest of your body"
  In the tour: Inside it is your spinal cord, which carries messages from your brain.
  KidsHealth (kids) — Your Bones
• "Your lower jawbone is the only bone in your head you can move"
  In the tour: Tap: Your jawbone: the only bone in your head you can move.
  KidsHealth (kids) — Your Bones
• "The first seven pairs of ribs attach in the front to the sternum"
  In the tour: Tap: Your breastbone, or sternum. Your top ribs join on to it, at the front.
  KidsHealth (kids) — Your Bones
• "The collarbone (also called the clavicle) is the bone that connects the breastbone to the shoulder"
  In the tour: Tap: Your collarbone, or clavicle. It joins your breastbone to your shoulder. Can you feel it?
  KidsHealth (parents) — Broken Collarbone
• "Each arm is attached to a shoulder blade or scapula"
  In the tour: Tap: Your shoulder blade, or scapula. Each arm is joined on to one.
  KidsHealth (kids) — Your Bones
• "the humerus, which is above your elbow, and the radius and ulna, which are below the elbow"
  In the tour: Tap: Your humerus: the bone above your elbow. Your radius and ulna: the two bones below your elbow.
  KidsHealth (kids) — Your Bones
• "Each finger on your hand has three bones, except for your thumb, which has two"
  In the tour: Tap: Each finger has three bones, and your thumb has two.
  KidsHealth (kids) — Your Bones
• "The pelvis is a bowl-shaped structure that supports the spine"; "Your legs are attached to a circular group of bones called your pelvis"
  In the tour: Tap: Your pelvis: a bowl of bones that holds up your backbone. Your legs join on to it.
  KidsHealth (kids) — Your Bones
• "The bone that goes from your pelvis to your knee is called the femur"; "It's the longest bone in your body"
  In the tour: Your femur, in your thigh, is your longest bone.
  KidsHealth (kids) — Your Bones
• "A triangular-shaped bone called the patella, or kneecap"; "Below the knee are two other leg bones: the tibia and the fibula"
  In the tour: Tap: Your kneecap, or patella: a triangle-shaped bone at the front of your knee. Your tibia and fibula: the two bones below your knee.
  KidsHealth (kids) — Your Bones
• "Each toe has three tiny bones, except for your big toe, which has just two"
  In the tour: Tap: Each toe has three tiny bones, and your big toe has two.
  KidsHealth (kids) — Your Bones
• "Compact bone. This part is smooth and very hard"
  In the tour: On the outside: compact bone, hard and smooth.
  KidsHealth (kids) — Your Bones
• cancellous bone "looks a bit like a sponge"; "Cancellous bone is not quite as hard as compact bone, but it is still very strong"
  In the tour: Near the ends: spongy bone. It looks like a sponge, but it's very strong.
  KidsHealth (kids) — Your Bones
• the periosteum: "It's a thin, dense membrane that contains nerves and blood vessels that nourish the bone"
  In the tour: Tap: The periosteum: a thin skin round the outside of a bone, with blood vessels that feed it.
  KidsHealth (kids) — Your Bones
• "Bone marrow is sort of like a thick jelly, and its job is to make blood cells"
  In the tour: And in the middle, bone marrow, like a thick jelly. Bone marrow makes blood cells.
  KidsHealth (kids) — Your Bones
• "RBCs are made in the inside part of bones called the bone marrow"; "Each day, the body makes new RBCs"
  In the tour: Bone marrow makes blood cells. Lots of them, every day! Here's a new red blood cell. Its red blood cells are made right here!
  KidsHealth (kids) — Blood
• white blood cells: new cells are formed "some in the bone marrow", and "Different types of WBCs fight germs"; platelets are "made by the bone marrow" and "help in the clotting process"
  In the tour: White blood cells and platelets are made here too. (Tap: white blood cells that fight germs, and platelets that help make clots.)
  KidsHealth (kids) — Blood
• "Growth plates are the areas of new bone growth in children and teens"; "There are usually two growth plates in each long bone. They add length and width to the bone"; "Most growth plates are near the ends of long bones"
  In the tour: Near the ends of your long bones are growth plates. They help you grow taller. New bone grows here, and the bone gets a little longer!
  KidsHealth (parents) — Growth Plates
• milk and other dairy foods "contain calcium, which helps bones harden and become strong"
  In the tour: Calcium, from milk and other foods, helps bones get hard and strong.
  KidsHealth (kids) — Your Bones
• "Vitamin D helps the body absorb calcium"; "Our bodies make vitamin D when our skin is exposed to the sun"
  In the tour: Sunshine on your skin helps your body use calcium.
  KidsHealth (parents) — Vitamin D
• "everyone is growing up — it's just that they're doing it at their own pace"
  In the tour: Everyone grows at their own pace.
  KidsHealth (kids) — Feeling Too Tall or Too Short
• "The place where two bones meet is called a joint"
  In the tour: Joints: the places where two bones meet.
  KidsHealth (kids) — Your Bones
• "Your elbows and knees each have hinge joints, which let you bend and then straighten your arms and legs"; ball and socket joints are at "your shoulders and hips" and "allow for lots of movement in every direction"
  In the tour: Your knee is a hinge joint. It bends and straightens, like a door. Your hip is a ball and socket joint. It swings all around!
  KidsHealth (kids) — Your Bones
• "Bones are held together at the joints by ligaments, which are like very strong rubber bands"
  In the tour: Ligaments hold your bones together, like strong rubber bands.
  KidsHealth (kids) — Your Bones
• tendons are "special connector pieces between bone and muscle"; "Muscles provide the tug on the bones"
  In the tour: Muscles pull on your bones to make them move.
  KidsHealth (kids) — Your Muscles
• "In most species, the hind legs and feet are much larger and more powerful than the forelimbs"; the tail helps "the kangaroo or wallaby balance and turn during hopping"
  In the tour: My big back legs and my tail help me hop!
  San Diego Zoo Wildlife Alliance — Kangaroo and Wallaby
• a cast "keeps the broken bone from moving while it heals"
  In the tour: A cast keeps it still while it mends.
  KidsHealth (kids) — How Broken Bones Heal
• "the body forms a blood clot (or hematoma) around the broken bone"; a callus "joins the broken bones together. It's soft at first, then gets harder and stronger over the following weeks"; "New bone forms in the weeks to months after a break"
  In the tour: Sometimes a bone can crack. But bones know how to mend. Inside, a clot fills the crack. Then a callus grows round it, like a bridge. The callus gets harder, and new bone smooths it over.
  KidsHealth (kids) — How Broken Bones Heal
• healing in children "occurs at a much faster rate"; "Young children have excellent remodelling potential"
  In the tour: Children's bones mend really well!
  The Royal Children's Hospital Melbourne — Fracture healing
• "strengthen your bones … through exercise like running, jumping, dancing, and playing sports"
  In the tour: Running, jumping, dancing and playing, in the ways you can, help keep your bones strong.
  KidsHealth (kids) — Your Bones

Every word it says

The whole script, for reading along, or for a child who'd rather read than listen.

1. Click, clack!

• Hello! I'm Wallaby. Boing, boing!
• This is your skeleton: all your bones together. It holds you up!
• A grown-up has 206 bones. A baby has about 300, and some of them join together as you grow.
• Feel your knee, your elbow, your ribs. Those are bones!

2. Keeping you safe

• Your skull keeps your brain safe, like a helmet.
• Your ribs are like a cage round your heart and lungs.
• Your backbone: 33 little bones, stacked up.
• Inside it is your spinal cord, which carries messages from your brain.

3. Inside a bone

• Your femur, in your thigh, is your longest bone. Let's look inside it!
• On the outside: compact bone, hard and smooth.
• Near the ends: spongy bone. It looks like a sponge, but it's very strong.
• And in the middle, bone marrow, like a thick jelly.

4. The blood factory

• Bone marrow makes blood cells. Lots of them, every day!
• White blood cells and platelets are made here too.
• Here's a new red blood cell. Into a blood vessel it squeezes, and out of the bone it goes!
• Remember the Lub-Dub Club? Its red blood cells are made right here!

5. Growing up

• Near the ends of your long bones are growth plates. They help you grow taller.
• Calcium, from milk and other foods, helps bones get hard and strong.
• New bone grows here, and the bone gets a little longer!
• Sunshine on your skin helps your body use calcium.
• Everyone grows at their own pace.

6. Bend and swing

• Hello, Emu! Let's bend and swing.
• Joints: the places where two bones meet.
• Your knee is a hinge joint. It bends and straightens, like a door.
• Your hip is a ball and socket joint. It swings all around!
• Ligaments hold your bones together, like strong rubber bands.

7. Hop to it!

• Muscles pull on your bones to make them move.
• My big back legs and my tail help me hop!
• You'll meet your muscles in the Heave-Ho Club!

8. A bone mends

• Oops! Sometimes a bone can crack. But bones know how to mend.
• A cast keeps it still while it mends.
• Inside, a clot fills the crack. Then a callus grows round it, like a bridge.
• The callus gets harder, and new bone smooths it over.
• Children's bones mend really well!

9. Strong bones

• Running, jumping, dancing and playing, in the ways you can, help keep your bones strong.
• Thanks for clicking and clacking with me. Welcome to the Click-Clack Club!

The quiz

Quiz time! Let's see what you remember. The right answers are in bold.

1. How many bones does a grown-up have? (206 / 6 / 2,000)
2. What keeps your brain safe? (Your knee / Your skull / Your toes)
3. What does bone marrow make? (Sweat / Fingerprints / Blood cells)
4. Which joint bends like a door? (Your knee / Your skull / Your ribs)
5. What helps your bones grow strong? (Bubbles / Calcium, from milk and other foods / Sand)
6. What helps a broken bone mend? (Wiggling it / Nothing at all / A cast, to keep it still)

What it needs, and what we collect

A recent browser on a phone, tablet or computer. The first visit downloads about 11 MB, and after that it keeps working with no signal. Nothing about your child is collected: the My mob card and the sound setting are kept on your own device. The privacy page has the whole story.

More in the series: What Makes Me, with the Lub-Dub Club, the Huff-Puff Club, the Munch-Crunch Club, the Mix-Fix Club, the Zip-Zap Club, the Drip-Drop Club, the Five-Alive Club and the Tickle-Prickle Club.