LAB · MIDDLE SCHOOL (6–8)

🦠 Your Microbiome Adventure

Trillions of microbes live in your gut, mouth, and skin — and they shape digestion, immunity, AND mood. Meet your tiny tenants.

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How to do this lab — read me first!

1.Take the pre-quiz below. Type your answer into the box for each question — it's okay if you're not sure! This shows what you already know. Spelling doesn't have to be perfect, and CAPS or lowercase both work the same.
2.Read the lab sections below the quiz — they explain the science in plain words. Tap "Go deeper" on any card for extra info.
3.Work through each lab module by tapping the bubbles near the top. Read it, then press "Mark module complete" to unlock the next one.
4.Do the hands-on sorting activity — use the up/down arrows to put the items in the right order, then press Check my order.
5.Take the post-quiz. It unlocks after you finish everything above. Type your answers in — short answers are fine, just write the main idea.
6.Sign in to save your scores and earn a badge. No account? You can still explore the whole lab.

💡 Stuck on a question? Scroll back and re-read the section about it, then return and try again. There's no time limit!

📝 Pre-quiz — what do you already know?

✏️ Type your answer in the box. Spelling close enough is OK — UPPER or lower case both work.

1. Most microbes living in you are…

2. Fiber feeds…

3. Antibiotics affect…

4. Roughly how many microbial cells live in/on the average human body?

5. Most of your serotonin (a mood neurotransmitter) is actually produced in your…

6. ‘Prebiotic’ vs ‘probiotic’:

7. Fecal microbiota transplants (FMT) are used clinically to treat…

Who lives in you

Your body hosts roughly the same number of microbial cells as human cells. They’re mostly helpful — and you can’t live without them.

Gut-brain axis

Gut microbes help produce ~90% of your serotonin (a mood neurotransmitter) and signal directly to your brain via the vagus nerve.

Go deeper

This is why antibiotics, ultra-processed diets, and high stress can mess with mood — they all reshape the microbiome. Research is still early but the link is clear.

Feed the good bugs

· Fiber: beans, oats, fruit, vegetables, whole grains
· Fermented foods: yogurt, kimchi, sauerkraut, kefir
· Variety = diversity (eat lots of different plants weekly)
· Limit ultra-processed food (microbe diversity suffers)

When antibiotics matter

Antibiotics save lives — but they wipe many helpful bacteria too. Take them ONLY when prescribed, and finish the course. Eating fiber + fermented foods afterward helps rebuild.

Key vocabulary

Microbiome: All the microbes (bacteria, viruses, fungi) living in or on your body.
Prebiotic: Fiber that feeds beneficial microbes (e.g., onions, oats, garlic, bananas).
Probiotic: Live beneficial microbes themselves (yogurt, kimchi, sauerkraut).
Gut-brain axis: The two-way communication between your gut microbes and your brain.

Lab modules

Work through each module in order. Mark each one complete to unlock the post-quiz.

Meet your microbes

Roughly 30 trillion microbial cells live in/on you — about as many as your human cells. Most are helpful or neutral.

Where they live

· Gut (largest population)
· Mouth & skin
· Nose & airways
· Diverse niches do different jobs

Gut–brain axis

Gut microbes produce ~90% of your serotonin and signal the brain via the vagus nerve. Diet → microbes → mood is a real loop.

Key takeaways from this module

You're 50/50 human cells and microbes.
Most microbes are partners, not enemies.
Gut microbes shape mood, immunity, AND digestion.

Hands-on activity: Build a microbiome-friendly day

Sequence a day of eating + habits that feed helpful gut microbes.

1.Whole-grain dinner with greens
2.Fiber breakfast (oats + berries)
3.Movement + sleep (microbes thrive on rhythm)
4.Variety at lunch (beans + veg)
5.Fermented snack (yogurt/kimchi)

Apply it — real-world challenge

For one week, try to eat 20+ different plant foods (every herb, spice, bean, fruit, veg counts). How does your digestion feel by day 7?

Post-quiz locked

Finish all 4 lab modules (0/4 done). Complete the hands-on activity above.