The Snap-Trap Club

A 3D tour of the body's germ-fighters for children about five to eight. Inside a see-through child: the skin, mucus and tears keeping germs out, white blood cells made in the bone marrow and gobbling germs up, the spleen cleaning the blood, and little lymph nodes trapping germs. Then it looks inside the spleen, where antibodies stick to germs and the body remembers them. Washing hands, sneezing into an elbow and a good sleep all help. Free, with no ads and no sign-ups.

What your child will learn

• Germs are tiny living things, too small to see. Bacteria and viruses are two kinds. Some germs can make people feel unwell, and some are helpful, like the bacteria in our tummies.
• The body keeps germs out: skin like a raincoat, tears and spit that fight germs, and sticky mucus in the nose.
• We can help: washing hands with soap and water for 20 seconds, before eating and after the toilet, and sneezing into an elbow, not hands.
• White blood cells are the germ-fighters. They're made in the bone marrow, travel in the blood looking for germs, and some gobble germs right up.
• The spleen cleans the blood, taking out tired old red blood cells, and its white blood cells catch germs. Lymph nodes, little bean-shaped germ traps in the neck, armpits and the tops of the legs, sit along thin lymph vessels.
• Antibodies, little Y-shapes, stick to germs so white blood cells can find them, and the body remembers each germ, so next time it's even faster. All of this together is the immune system. A good sleep, lots of different foods, and moving and playing help it.

How it works

Story. A quokka tells it in nine short chapters. Germs float round the child; one lands on the arm and runs off the skin like rain off a raincoat, one is caught in the nose's mucus, and one rides on a hand until the hands are washed while a count goes up to 20. The galah drops in as the child sneezes into its elbow. A ringed white blood cell leaves the bone marrow, travels in the blood round by the heart to the spleen, and gobbles a germ; the chapter waits for it. The page turns to a close-up inside the spleen, drawn big and simple: red blood cells squeeze through a filter while a tired old one is taken out, and a white blood cell catches a germ. A germ is caught in a lymph node, snap! Back inside the spleen, antibodies stick to a germ, it's gobbled, and when the same kind of germ comes again the body remembers it. Every word is spoken and shown.

Explore. Turn the child round, peek inside (the skin fades away to show the germ-fighters), or tap any part to hear its name and what it does. Tap the spleen to see the close-up. Four buttons: Wash (a germ is washed off a hand, with a count to 20), Sneeze (into the elbow), Gobble (a white blood cell gobbles a germ in the blood) and Sleep (the eyes close, and the germ-fighters glow). Follow a white blood cell takes one from the bone marrow to the spleen, 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. Mucus, bone marrow, lymph vessels and the spleen's filter are named in the story and in Explore, but kept off the card.

• Germ: a tiny living thing, too small to see.
• Bacteria: one kind of germ. Some are helpful, and live in your tummy.
• Virus: another kind of germ, even smaller than bacteria.
• White blood cell: a germ-fighter in your blood.
• Antibody: a little Y-shape that sticks to a germ.
• Spleen: the organ that cleans your blood and catches germs.
• Lymph node: a little germ trap, shaped like a bean.
• Immune system: all your germ-fighters, working together.

For grown-ups: the immune system, in detail

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

1. Barriers first. Skin is a waterproof barrier; mucus and tiny hairs (cilia) in the airways trap particles and sweep them away; tears, saliva and skin oil contain enzymes that kill bacteria; stomach acid deals with many germs that are swallowed. The tour shows the skin, the nose's mucus, tears and spit.
2. White blood cells (leukocytes) are made in the bone marrow. Phagocytes, such as neutrophils and macrophages, engulf and digest germs (the tour's "gobble"). Lymphocytes are the specialists: B cells make antibodies, and T cells help direct the response and destroy infected cells. White blood cells travel in the blood and the lymph, and gather where they're needed.
3. The spleen, under the ribs on the left, filters the blood. Its red pulp removes old and damaged red blood cells (macrophages take them in; the tour shows them shrinking away), and its white pulp, clumps of lymphocytes round the branches of the splenic artery, makes antibodies and catches germs in the blood.
4. The lymphatic system is a network of thin vessels carrying lymph, the fluid that bathes the body's tissues, back towards the blood. Bean-shaped lymph nodes along the way filter it, and lymphocytes there trap and destroy germs. Clusters sit in the neck, armpits and groin. Lymph nodes can feel a little swollen when they're busy.
5. Antibodies are Y-shaped proteins made by B cells. Each fits one particular germ (its antigen); they stick to it, mark it for phagocytes and can stop it working. After an infection, memory cells stay in the body, so the next time the same germ arrives the response is faster and stronger, often before it can make us unwell.
6. Vaccines (kept out of the story and quiz, as agreed) use this memory: they teach the immune system to recognise a germ without having the illness first. KidsHealth: "If you've had your shots (vaccines), your body is extra-prepared to fight off serious illnesses." Your doctor or child health nurse can tell you about your child's immunisations, as can regular check-ups.
7. Helpful bacteria live in the gut in huge numbers and help us use the nutrients in our food; most germs we meet do us no harm.

Also left out: the thymus and tonsils, complement, fever and inflammation, T cells by name in the story, and allergies.

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

• Wash your hands together and count slowly to 20 (or sing "Happy Birthday" twice) while you scrub: palms, backs, between the fingers and the thumbs.
• Practise the elbow sneeze: a pretend "Achoo!" into the crook of your arm.
• Feel gently under the angle of your jaw and in your armpit: that's where some lymph nodes sit (they're usually too small to feel).
• Talk about the helpful bacteria that live in our tummies and help us use our food.
• The sheet to print has the germ-fighters to label, hand-washing pictures to put in order, and a germ-fighting week to tick off.

For every child, and every body

The tour is about how the body keeps us well, not about being ill. It says only once, gently, that "some germs can make people feel unwell", and shows no illness, no hospitals and no needles. Germs are drawn as friendly shapes with no faces, never scary, and no child is ever shown as dirty or blamed: skipping hand-washing is a bar of soap with a cross beside it. Food is "lots of different foods", with nothing good or bad, and moving and playing are "in the ways you can", so every body is included. Some children have immune conditions, allergies, or get unwell more often; the tour says nothing that suggests that's anyone's fault. The germ-fighting week on the sheet isn't a test: every tick counts.

• 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.
• Everything has its own shape as well as colour: the white blood cell is a lumpy cell in an orange ring, a bacterium a hairy rod, a virus a knobbly ball, an antibody a Y, the filter a row of bars, and remembering a star.
• If your device asks for less motion, the camera cuts instead of flying, the page turns without the iris, and nothing spins, wobbles or flows.

What's simplified, and why

• Only the spleen, three pairs of lymph-node clusters, a few lymph vessels and the thigh bones' marrow are drawn; really there are hundreds of lymph nodes and marrow in many bones.
• White blood cells are drawn as one kind of soft round cell; really there are several kinds (phagocytes, lymphocytes and more).
• The close-up inside the spleen is a flat cut-away drawn like a picture book: one blood vessel in and one out, a single row of filter bars for the red pulp, and three pale islands for the white pulp.
• A tired old red blood cell is shown being stopped at the filter and shrinking away; really, white blood cells called macrophages take it in. The gobbling white blood cell is shown catching germs.
• Germs, cells and antibodies are drawn many times bigger than they are, and not to scale with one another; one germ is drawn as a rounded rod with little hairs.
• Remembering a germ is shown as a star on one white blood cell, and 'even faster' as quicker antibodies and a quicker gobble.
• Germs round the child are drawn many times bigger than they are, as friendly shapes with no faces: rounded rods with little hairs for bacteria and knobbly balls for viruses.
• A germ landing on the arm is shown running off the skin like rain off a raincoat; really, germs can sit on the skin, and the skin stops them getting inside.
• The count to 20 while washing pops up faster than real seconds in the story, so the chapter doesn't stop for 20 seconds; the Wash button counts a little slower.
• The white blood cell's way is drawn as one route: out of the right thigh bone's marrow, up through the blood to the heart, and on to the spleen.
• A germ caught in a lymph node is shown travelling up one lymph vessel, from the top of the leg to the armpit.
• The mucus that traps germs is shown in the nose; the source describes mucus and tiny hairs trapping dust and germs along the airways.

Where the facts come from

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

• Germs "are tiny organisms, or living things, that can cause disease"; "Germs are so tiny that they're microscopic. This means you need to use a microscope to see them."
  In the tour: Germs are tiny living things, too small to see. (Tap, close-up: A germ, drawn big. Really, germs are too small to see! Card: Germ: a tiny living thing, too small to see. Quiz: How big are germs? Too tiny to see.)
  KidsHealth (kids) — What Are Germs?
• Germs are living things "that can cause disease".
  In the tour: Some germs can make people feel unwell, so your body keeps them out. (The one gentle line, as agreed.)
  KidsHealth (kids) — What Are Germs?
• "Good bacteria live in our intestines and help us use the nutrients in the food we eat"
  In the tour: And some germs are helpful. Some live in your tummy, and help you use your food! (Card: Bacteria: one kind of germ. Some are helpful, and live in your tummy.)
  KidsHealth (kids) — What Are Germs?
• "Bacteria are tiny, one-celled creatures"; "Viruses are smaller than bacteria."
  In the tour: (Card: Virus: another kind of germ, even smaller than bacteria.)
  KidsHealth (kids) — What Are Germs?
• "skin – a waterproof barrier that secretes oil with bacteria-killing properties"
  In the tour: Your skin keeps germs out, like a raincoat. (Tap: Your skin. It keeps germs out, like a raincoat.)
  Better Health Channel — Immune system explained
• "body fluids like skin oil, saliva and tears contain anti-bacterial enzymes that help reduce the risk of infection"
  In the tour: Tears and spit help fight germs, too. (Tap: Your mouth. Spit helps fight germs.)
  Better Health Channel — Immune system explained
• "Mucus and tiny hairs trap dust and germs"
  In the tour: And sticky mucus in your nose traps them! (Tap: Your nose. Sticky mucus inside it traps germs.)
  healthdirect — Respiratory system
• "When you touch your eyes, nose or mouth, the germs can spread to these vulnerable areas."; KidsHealth: germs pass "by touching something that is contaminated, like shaking hands with someone who has a cold and then touching your own nose"
  In the tour: Germs can hitch a ride on your hands.
  healthdirect — Hand washing
• "Encourage your child to wash their hands with soap and water for 20 seconds." (also healthdirect Hand washing: "Rub your hands together for at least 20 seconds"; KidsHealth: "rub your hands together for at least 20 seconds")
  In the tour: Soap and water, for 20 seconds. Count with me! (Tap: Your hands. Wash them with soap and water, and germs wash away. Button: Wash! Soap and water, for 20 seconds. Quiz: 20 seconds.)
  healthdirect — Personal hygiene for children
• Wash hands "before eating or making food" and "after going to the toilet"
  In the tour: Wash before you eat, and after the toilet. Bye-bye, germs!
  healthdirect — Personal hygiene for children
• "Most germs are spread through the air in sneezes, coughs, or even breaths."
  In the tour: Germs fly out in sneezes and coughs.
  KidsHealth (kids) — What Are Germs?
• "If you don't have a tissue, sneeze or cough into your elbow. Do not use your hands." "Always wash your hands after sneezing or coughing."
  In the tour: So sneeze into your elbow, not your hands. Achoo! / Then wash your hands, too. (Tap: Your elbow. Sneeze into it, not your hands! Button: Achoo! Into your elbow. Quiz: Into your elbow.)
  healthdirect — Personal hygiene for children
• "White blood cells, also called leukocytes, are part of this defense system."; KidsHealth (What's Blood?): "Different types of WBCs fight germs, such as bacteria and viruses."
  In the tour: White blood cells are your germ-fighters. (Card: White blood cell: a germ-fighter in your blood.)
  KidsHealth (kids) — Your Immune System
• "White blood cells are made in your bone marrow"; KidsHealth: bone marrow is "a thick, spongy jelly inside your bones"
  In the tour: They're made in your bone marrow, inside your bones. (Taps: Bone marrow… It makes your white blood cells. / Your bones. White blood cells are made in the marrow inside them. Follow: A new white blood cell, made in the bone marrow.)
  Better Health Channel — Immune system explained
• "White blood cells move through blood and tissue throughout your body, looking for foreign invaders"
  In the tour: Off it goes, in the blood, looking for germs. (Follow: Off it goes in the blood, looking for germs. / White blood cells, on the lookout for germs!)
  Better Health Channel — Immune system explained
• "With each heartbeat, the heart pumps blood throughout our bodies"
  In the tour: (Tap: Your heart. It pumps your blood, with your white blood cells in it, all round your body. Follow: Round by your heart it goes.)
  KidsHealth (kids) — What's Blood?
• "Some types of white blood cells, called phagocytes, chew up invading organisms."
  In the tour: Some white blood cells gobble germs right up! Gobble! (Tap: A white blood cell… It catches germs, and gobbles them up! Button: Gobble! A white blood cell gobbles a germ. Follow: Into the spleen. A germ! Gobble! Quiz: White blood cells.)
  KidsHealth (teens) — The Immune System
• "The spleen is located in the upper left part of the belly under the ribcage."
  In the tour: This is your spleen, up here under your ribs. (Tap: Your spleen, up on the left, under your ribs…)
  KidsHealth (teens) — Spleen and Lymphatic System
• "The spleen is a blood-filtering organ that removes microbes and destroys old or damaged red blood cells."; Better Health (Spleen): "The red pulp filters the blood and removes old and defective blood cells."; KidsHealth: "The spleen acts as a filter. It weeds out old and damaged cells"
  In the tour: Your spleen cleans your blood. Tired old red blood cells are taken out. (Taps: …It cleans your blood and catches germs. / Red blood cells. Tired old ones are taken out, here in your spleen. / The filter: it picks out tired old red blood cells, and germs too. Card: Spleen. Quiz: Your spleen.)
  Better Health Channel — Immune system explained
• The spleen "contains white blood cells called lymphocytes and macrophages. These cells work to attack and destroy germs."
  In the tour: And white blood cells catch germs, snap!
  KidsHealth (teens) — Spleen and Lymphatic System
• "Blood enters the spleen via the splenic artery, which subdivides into many tiny branches."
  In the tour: (Tap, close-up: Blood vessels: tubes that bring blood into your spleen, and take it out again.)
  Better Health Channel — Spleen
• "Antibodies are made inside the white pulp."; "Each branch is encased in a clump of lymphocytes"
  In the tour: Drawn: antibodies come out of a white blood cell in a pale island round a branch of the blood vessel.
  Better Health Channel — Spleen
• "Lymph nodes are small, bean-shaped organs."; Better Health: lymph nodes "trap microbes"
  In the tour: Lymph nodes: little germ traps, shaped like beans. (Taps for the lymph nodes. Card: Lymph node: a little germ trap, shaped like a bean.)
  Britannica Kids — Lymphatic system
• "Most of our lymph nodes are in clusters in the neck, armpit, and groin area."
  In the tour: You have them in your neck, your armpits, and the tops of your legs.
  KidsHealth (teens) — Spleen and Lymphatic System
• Lymph nodes "are found at certain points along the lymphatic vessels"; "Lymph nodes remove antigens from the lymph." Better Health (Lymphatic system): "Viruses and cancer cells are also trapped and destroyed in the lymph nodes" (the story says only that germs are caught).
  In the tour: Lymph vessels join them up, and germs get caught inside. Snap, trap! (Tap: Lymph vessels: thin tubes that join your lymph nodes together.)
  Britannica Kids — Lymphatic system
• "Each antibody structure consists of two heavy chains and two light chains, which join to form a Y-shaped molecule."; "Antibodies bind to these unwanted substances in order to eliminate them from your system."
  In the tour: Antibodies: little Y-shapes that stick to germs. (Tap: Antibodies… so white blood cells can find them. Card: Antibody: a little Y-shape that sticks to a germ.)
  Cleveland Clinic — Antibodies
• "The antibodies then mark these antigens for destruction."
  In the tour: They help your white blood cells find the germs.
  Better Health Channel — Immune system explained
• "The immune system keeps a record of every microbe it has ever defeated"; "it can recognise and destroy the microbe quickly if it enters the body again, before it can multiply"
  In the tour: And your body remembers each germ, so next time it's even faster!
  Better Health Channel — Immune system explained
• "Healthy kids can help their immune systems by washing their hands regularly to prevent infections, eating nutritious foods, getting plenty of exercise, getting enough sleep, and getting regular medical checkups." (Checkups and vaccines are for the guide only, as agreed.)
  In the tour: You can help your germ-fighters. / A good sleep, lots of different foods, and moving and playing, in the ways you can. / And washing your hands! (Button: Sleep! A good sleep helps your germ-fighters. Quiz: A good sleep.)
  KidsHealth (kids) — Your Immune System
• "White blood cells, also called leukocytes, are part of this defense system" (the immune system: the body's germ-fighters, together).
  In the tour: (Card: Immune system: all your germ-fighters, working together. Tap: Your germ-fighters: your skin, your spleen, your lymph nodes and your white blood cells…)
  KidsHealth (kids) — Your Immune System

Every word it says

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

1. Snap, trap!

• Hello! I'm Quokka. Let's meet your germ-fighters!
• Germs are tiny living things, too small to see.
• Some germs can make people feel unwell, so your body keeps them out.
• And some germs are helpful. Some live in your tummy, and help you use your food!

2. Keep out!

• Your skin keeps germs out, like a raincoat.
• Tears and spit help fight germs, too.
• And sticky mucus in your nose traps them!

3. Wash, wash, wash

• Germs can hitch a ride on your hands.
• Soap and water, for 20 seconds. Count with me!
• Wash before you eat, and after the toilet. Bye-bye, germs!

4. Achoo!

• Hello, Galah!
• Germs fly out in sneezes and coughs.
• So sneeze into your elbow, not your hands. Achoo!
• Then wash your hands, too.

5. Germ-fighters

• White blood cells are your germ-fighters.
• They're made in your bone marrow, inside your bones.
• Off it goes, in the blood, looking for germs.
• Some white blood cells gobble germs right up! Gobble!

6. Inside the spleen

• This is your spleen, up here under your ribs.
• Let's look inside it!
• Your spleen cleans your blood. Tired old red blood cells are taken out.
• And white blood cells catch germs, snap!

7. Germ traps

• Lymph nodes: little germ traps, shaped like beans.
• You have them in your neck, your armpits, and the tops of your legs.
• Lymph vessels join them up, and germs get caught inside. Snap, trap!

8. I remember you!

• Antibodies: little Y-shapes that stick to germs.
• They help your white blood cells find the germs.
• And your body remembers each germ, so next time it's even faster!

9. Strong defenders

• You can help your germ-fighters.
• A good sleep, lots of different foods, and moving and playing, in the ways you can.
• And washing your hands!
• Welcome to the Snap-Trap Club!

The quiz

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

1. How big are germs? (Too tiny to see / As big as a ball / As big as a shoe)
2. How long should you wash your hands? (1 second / 20 seconds / All day)
3. Where should you sneeze? (Into your hands / Into the air / Into your elbow)
4. What gobbles up germs? (White blood cells / Toenails / Hair)
5. Which part cleans your blood and catches germs? (Your knee / Your spleen / Your nose)
6. What helps your germ-fighters? (Staying up all night / Skipping hand-washing / A good sleep)

What it needs, and what we collect

A recent browser on a phone, tablet or computer. The first visit downloads about 10 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, the Tickle-Prickle Club, the Click-Clack Club and the Heave-Ho Club.