Experiments for Chemistry Assembly Live

 

YOUR BODY IS A CHEMISTRY LAB!

A Live Experiment Show for School Assembly

 

Theme: Body & Health Chemistry

Presented by: Chemistry Department

Every breath you take, every meal you eat, every drop of blood in your veins — it is all chemistry. Today, WE will prove it!

 

ROLES ON STAGE PERFORMERS & AUDIENCE

ASSISTANT A:  Performs experiments step by step, announces observations

ASSISTANT B:  Holds up BODY FACT cards, manages voting, interacts with audience

AUDIENCE:  Votes, predicts outcomes, answers questions, shouts the catchphrase

 

SHOW CATCHPHRASE:  HOST says: 'Your body does this EVERY DAY — believe it or not?' Audience shouts: BELIEVE IT!

OPENING SCRIPT Welcome & Introduction

[HOST walks on stage confidently. ASSISTANT A and B stand at the experiment table.]

 

HOST:  Good morning, everyone! Quick question — how many of you had breakfast today?

AUDIENCE:  Most hands go up!

HOST:  And how many of you are breathing right now?

AUDIENCE:  Everyone raises hands, laughs!

HOST:  Perfect. You are ALREADY doing chemistry. Right now. This very second. Because your body — all 37 trillion cells of it — is one of the most sophisticated chemistry laboratories ever created. And today, we are going to prove it. With five simple experiments using everyday materials — we will show you the chemistry happening inside YOU, every single day. Are you ready?

AUDIENCE:  YES!

HOST:  Assistant A, Assistant B — let us begin!

 

  EXPERIMENT 1:  THE DIGESTION DETECTIVE — SALIVA & STARCH

  Body Connection: Your mouth starts digesting food the moment you take a bite!

 

Concept:  Enzymes in saliva (amylase) break down starch — just like your digestive system does

Duration:  4-5 minutes

 

MATERIALS: 

2 small bowls or cups	Water in a cup
Plain cooked rice or a piece of plain white bread	A volunteer from the audience
Iodine solution (dilute) in a dropper	Disposable spoon / cotton swab

 

SAFETY NOTE:  Iodine is for demonstration only — do not ingest. Volunteer only chews and spits into cup, does not swallow iodine.

 

SCRIPT Experiment 1

HOST:  Tell me — what happens the moment you put food in your mouth?

AUDIENCE:  We chew it! It gets wet! Saliva!

HOST:  Saliva! That watery liquid in your mouth is not just water. It contains a chemical called AMYLASE — a digestive enzyme. And amylase has one very important job: it breaks down starch in your food into simpler sugars — before the food even reaches your stomach. Let us prove it!

[Assistant A shows two bowls: Bowl 1 has plain rice/bread. Bowl 2 is empty.]

HOST:  I need a brave volunteer. Do not worry — all you need to do is chew this tiny piece of bread for 30 seconds. Do NOT swallow. Then spit it gently into Bowl 2. Any volunteers?

AUDIENCE:  Hands shoot up! One volunteer is chosen.

[Volunteer chews bread for 30 seconds, spits into Bowl 2. Assistant A adds iodine to both bowls.]

ASSISTANT A:  Bowl 1 — the unchewed bread — turned deep blue-black! Bowl 2 — the chewed bread — stayed light brown or yellow. The colour did NOT change much!

HOST:  Why? Because iodine turns blue-black in the presence of starch. But the chewed bread had its starch BROKEN DOWN by amylase in the saliva — the starch was already digested! Iodine found no starch to react with!

HOST:  So — your body does this EVERY DAY — believe it or not?

AUDIENCE:  BELIEVE IT!

HOST:  Your mouth is your first digestive chemistry lab. Before the food reaches your stomach — it is already being chemically processed. That is enzyme chemistry!

 

  DID YOU KNOW?

Amylase is one of the most important enzymes in your body. Without it, your body could not extract energy from rice, bread, chapati, or potatoes. You are producing fresh amylase in your saliva right now as you sit here!

  CHEMISTRY CONCEPT:  Enzymes — Nature's Chemical Catalysts

Enzymes are biological molecules (mostly proteins) that speed up chemical reactions in the body without being consumed. Amylase in saliva breaks starch into maltose (a simpler sugar). This is why a piece of bread tastes slightly sweet if you chew it long enough — the starch is turning to sugar right in your mouth!

 

  EXPERIMENT 2:  BREATHING CHEMISTRY — PROVING CO2 IN YOUR BREATH

  Body Connection: Every exhale release carbon dioxide — a waste product of your cells!

 

Concept:  Exhaled air contains CO2, which turns a bicarbonate indicator solution from blue to yellow

Duration:  3-4 minutes

 MATERIALS: 

Bromothymol Blue (BTB) indicator solution (dilute) OR red cabbage juice	Water
2 clear glasses / beakers	A stopwatch or timer
A drinking straw (unused, clean)	Result label cards

SAFETY NOTE:  Use only food-safe or very dilute BTB. Student blows gently through straw — no deep hyperventilation. Do not share straws between students.

 

SCRIPT Experiment 2

HOST:  Every single second, you breathe in and breathe out. You know you breathe in oxygen. But what do you breathe OUT?

AUDIENCE:  Carbon dioxide! CO2!

HOST:  Yes — CO2. A waste gas produced when your cells burn glucose for energy. And we are going to PROVE that it is in your breath. Right now. Using chemistry.

[Assistant A fills two glasses with the BTB indicator solution — both are blue.]

ASSISTANT A:  Both glasses are blue — this indicator is blue when CO2 is absent or low.

HOST:  Now I need someone to gently blow through a straw into Glass 1. Just slow, steady breaths. Glass 2 is our control — no one touches it.

[Volunteer gently blows through straw into Glass 1 for 30-45 seconds. Audience watches eagerly.]

ASSISTANT A:  Glass 1 is changing! It is going from blue... to green... to YELLOW!

AUDIENCE:  Audience gasps and cheers!

HOST:  The CO2 in your breath dissolved into the water and formed CARBONIC ACID — a weak acid. This acid changed the colour of the indicator from blue to yellow. The chemistry of your breathing — visible right before your eyes!

HOST:  Your body does this EVERY DAY — believe it or not?

AUDIENCE:  BELIEVE IT!

HOST:  You take about 20,000 breaths a day. Each one is a chemistry reaction — releasing CO2 your cells have produced. Glass 2 is still blue — proving it is the CO2 in your breath causing the change, nothing else.

 

  DID YOU KNOW?

The CO2 in your blood is what triggers your brain to tell your lungs to breathe! When CO2 builds up, your brain sends the signal: breathe now! You are not just breathing for oxygen — you are breathing to release CO2.

  CHEMISTRY CONCEPT:  CO2 and Acid-Base Chemistry

CO2 + H2O forms H2CO3 (carbonic acid) — a weak acid. This lowers the pH of the solution, causing the indicator colour change. This is the same chemistry that happens in your blood — CO2 from cells dissolves in blood plasma, is carried to the lungs as bicarbonate, and exhaled. Without this process, your blood would become dangerously acidic.

 

  EXPERIMENT 3:  THE SKIN SHIELD — OIL, WATER & EMULSIFICATION

  Body Connection: Your skin produces natural oil to protect you — and it works like chemistry!

 

Concept:  Skin produces sebum (natural oil). Oil and water do not mix. Soap acts as an emulsifier — just like your body does.

Duration:  3-4 minutes

 

MATERIALS: 

A small bottle of cooking oil	A butter paper or brown paper piece
Water in a clear glass	Your own finger (natural skin oil!)
A drop of liquid dish soap	A torch/light for back-lighting effect

SAFETY NOTE:  Completely safe — no chemicals. Cooking oil and water only. Be careful not to spill oil on the floor.

 

SCRIPT Experiment 3

HOST:  Rub your finger gently on your forehead. Now press it on a piece of paper and hold it up to the light.

[HOST demonstrates. A translucent fingerprint spot appears on the paper.]

HOST:  See that? A faint, oily spot. Your skin is constantly producing a natural oil called SEBUM. It keeps your skin from drying out, protects against bacteria, and keeps moisture locked in. But why does skin produce OIL and not water? Let us find out.

[Assistant A pours water into the glass. Adds a small amount of oil.]

ASSISTANT A:  The oil and water are just sitting on top of each other — they refuse to mix!

HOST:  Why? Because water molecules are POLAR — they have a positive and a negative end. Oil molecules are NON-POLAR — no charge. Opposites attract in love stories — but in chemistry, like dissolves like! Oil and water stay separate.

HOST:  Now — what happens when we add soap?

[Assistant A adds one drop of dish soap and stirs gently. The liquids become cloudy — an emulsion forms.]

ASSISTANT A:  It mixed! It turned milky white — they are combining now!

HOST:  Soap is an EMULSIFIER — it has one end that likes water and one end that likes oil. It grabs both and forces them together. This is exactly how soap cleans your skin — it grabs the oil and dirt AND the water and washes everything away together. Your body does this EVERY DAY — believe it or not?

AUDIENCE:  BELIEVE IT!

HOST:  Every time you wash your hands, you are doing emulsification chemistry. And every time your skin produces sebum — it is protecting you with natural chemistry!

 

  DID YOU KNOW?

Bile, produced by your liver, acts as a biological emulsifier in digestion. It breaks fat into tiny droplets so digestive enzymes can act on them more efficiently. Your liver is doing the same job as dish soap — every time you eat!

  CHEMISTRY CONCEPT:  Emulsification — Mixing the Unmixable

An emulsifier has a hydrophilic (water-loving) head and a hydrophobic (water-fearing/oil-loving) tail. It surrounds oil droplets, making them stay suspended in water. This is the basis of soaps, detergents, bile in digestion, and even mayonnaise! The skin's sebum also contains emulsifying components that help the skin barrier function.

 

  EXPERIMENT 4:  TOOTH DEFENDER — LEMON ACID VS YOUR ENAMEL

  Body Connection: The acid in your food attacks your teeth every single day — here's the proof!

 

Concept:  Acid dissolves calcium carbonate (tooth enamel). Lemon juice is acidic — chalk is calcium carbonate — same chemistry as teeth dissolving

Duration:  3-4 minutes

 

MATERIALS: 

1 piece of white chalk (calcium carbonate)	A dropper
Fresh lemon juice in a small bowl	Paper plate or tray
A cup of water (neutral pH)	Optionally: a piece of eggshell (also CaCO3, just like teeth!)

SAFETY NOTE:  Lemon juice is acidic but food-safe. Do not rub lemon juice on actual teeth during the demo — the demo illustrates the concept using chalk as a safe substitute.

 

SCRIPT Experiment 4

HOST:  How many of you have ever had a toothache? Or been told to not eat too many sweets?

AUDIENCE:  Most hands go up.

HOST:  Your parents and dentists are giving you chemistry advice — whether they know it or not! Your tooth enamel — the hard white outer layer of your teeth — is made of calcium phosphate and calcium carbonate. And acids... are its worst enemy. Let us see why.

[Assistant A places chalk pieces on the plate. One piece goes into lemon juice. One goes into water.]

ASSISTANT A:  Watch carefully... the chalk in lemon juice is already fizzing!

AUDIENCE:  Ooooh! Bubbles!

HOST:  Those bubbles are CARBON DIOXIDE gas being released as the acid reacts with the calcium carbonate and dissolves it. The chalk in plain water? No reaction. No fizz.

HOST:  Now think — every time you drink a cold drink, eat pickles, have citrus juice, or even vinegar — that SAME reaction is happening on your tooth enamel. Very slowly. But every day. Over years, the enamel wears away — and that is how cavities begin.

HOST:  Your body does this EVERY DAY — believe it or not?

AUDIENCE:  BELIEVE IT!

HOST:  This is exactly why dentists say: rinse your mouth after eating sour or sweet foods. And why fluoride in toothpaste helps — it strengthens the crystal structure of enamel to resist acid attack. Chemistry is protecting your teeth every morning when you brush!

 

  DID YOU KNOW?

Saliva is your body's natural tooth protector! It is slightly basic, which neutralises the acid in your mouth after eating. People who have less saliva (dry mouth) get more cavities — because there is less natural neutralisation happening. Drinking water also helps rinse away acids.

  CHEMISTRY CONCEPT:  Acid + Carbonate Reaction

The reaction: CaCO3 (chalk/tooth enamel) + 2HCl (acid) forms CaCl2 + H2O + CO2. The fizzing bubbles are CO2 escaping. This is the same chemistry that causes stalactites and stalagmites to form in caves — rain (slightly acidic) dissolves limestone (calcium carbonate) over thousands of years. Your mouth is doing a gentler, slower version of this after every meal!

 

  EXPERIMENT 5:  IRON IN YOUR BLOOD — FINDING THE IRON IN YOUR BREAKFAST CEREAL

  Body Connection: Your blood contains real iron — and we can find it in your food!

 

Concept:  Iron is a mineral your body needs for haemoglobin in blood. Iron-fortified cereals contain actual iron particles that are magnetic!

Duration:  4-5 minutes

 

MATERIALS: 

1 cup of iron-fortified breakfast cereal (Corn Flakes, etc.)	A ziplock/plastic bag
Water (enough to make a cereal paste)	A white plate
A strong neodymium / bar magnet	A blender or the ability to crush cereal finely

SAFETY NOTE:  Magnets are safe. Ensure cereal is fully sealed in bag to avoid mess. Use only store-bought iron-fortified cereal.

 

SCRIPT Experiment 5

HOST:  Final experiment! And possibly the most surprising one. Let me ask you something: What is blood made of?

AUDIENCE:  Cells! Water! Plasma! Haemoglobin!

HOST:  Haemoglobin — excellent! Haemoglobin is the protein in your red blood cells that carries oxygen from your lungs to every cell in your body. And haemoglobin is built around... IRON. Actual iron. The same metal. Fe. Element 26 on the periodic table. And because iron is so important — food manufacturers ADD iron to your breakfast cereal. Actual tiny iron particles. And we can FIND them.

[Assistant A crushes iron-fortified cereal and places it in the ziplock bag. Adds a little water to make a fine paste. Seals the bag.]

HOST:  Now — Assistant A — run the magnet along the bottom of the bag. Slowly.

[Assistant A runs magnet along the outside of the bag. Dark iron particles visibly migrate and cluster toward the magnet.]

ASSISTANT A:  I can see tiny dark particles moving toward the magnet! They are collecting right here — along the magnet edge!

AUDIENCE:  WHOA! That is iron? In the cereal?!

HOST:  That is real metallic iron. In your breakfast. And when you eat it — your stomach acid dissolves it — and your intestines absorb it into your bloodstream — where it becomes part of your haemoglobin. Your body does this EVERY DAY — believe it or not?

AUDIENCE:  BELIEVE IT!

HOST:  If you do not get enough iron in your food — you get anaemia. Your haemoglobin drops. Your blood cannot carry enough oxygen. You feel tired, weak, and dizzy. Iron deficiency is one of the most common nutritional problems in India — especially among growing children and teenage girls. Eating iron-rich foods like green leafy vegetables, lentils, jaggery, and fortified cereals — is basic body chemistry!

 

  DID YOU KNOW?

The iron in your body is so precious that when old red blood cells are destroyed, your body RECYCLES the iron from them to make new red blood cells. Your spleen acts as a recycling facility! The average human body contains about 3-4 grams of iron — enough to make a small nail.

  CHEMISTRY CONCEPT:  Iron, Haemoglobin & Your Blood

Haemoglobin is a protein with four iron-containing 'haem' groups. Each haem group can bind one oxygen molecule — so one haemoglobin molecule carries 4 oxygen molecules. Iron must be in the Fe2+ (ferrous) form to bind oxygen. Vitamin C helps your body absorb iron better — which is why eating spinach with a squeeze of lemon is chemistry-smart eating!

 

CLOSING SCRIPT The Big Reveal

[All three performers line up. HOST addresses the whole assembly warmly.]

 

HOST:  Five experiments. Five moments of proof. And the same incredible fact proved each time: your body is a living, breathing, digesting, protecting, pumping chemistry laboratory. Every enzyme in your saliva. Every breath you exhale. Every drop of oil your skin makes. Every acid that meets your teeth. Every iron atom in your blood. It is all chemistry.

HOST:  Chemistry is not just something in a lab. It is not just formulas on a page. It is YOU. It is alive inside you right now. And the better you understand it — the better you can take care of yourself.

HOST: So the next time someone asks why you study chemistry — you tell them...

AUDIENCE:  BECAUSE I AM CHEMISTRY! (prompt audience to say this!)

HOST:  Exactly. Thank you all — and remember: eat iron-rich food, rinse after sour snacks, wash hands with soap, breathe well, and never stop being curious!

[All three bow. Upbeat music plays. END OF SHOW.]

 

 

QUICK REFERENCE All 5 Experiments at a Glance

S.No.	Experiment	Body Link	Concept	Result
1	Saliva & Starch	Digestion	Enzyme action	Iodine turns clear
2	Lung CO2 Test	Breathing	CO2 in exhaled air	Indicator turns yellow
3	Skin & Oil	Skin protection	Emulsification	Paper turns translucent
4	Lemon Bleach	Teeth & acid	Oxidation	Ink disappears
5	Heartbeat & Iron	Blood & iron	Magnetic iron in cereal	Iron filings appear

TEACHER PREPARATION CHECKLIST Before the Assembly

 

-       Prepare BTB indicator: Dissolve 0.1g BTB powder in 15ml ethanol, then dilute with water to a blue colour. Store in a dropper bottle.

-       Prepare iodine solution: Use 1% iodine solution from the school lab. Test it on starch paper before the show.

-       Crush cereal fine: A finer powder gives more visible iron extraction. Blend if possible. Store in the ziplock bag with water the day before.

-       Test the magnet: Neodymium magnets work best. Test cereal iron extraction at home first. Run magnet slowly for best results.

-       Brief student assistants: Rehearse all 5 experiments. They should know what to announce for each observation.

-       Microphone & table: Set up a wide table with a plastic cover. Use a mike for the HOST — the show must be heard at the back row.

-       Volunteer plan: Identify 2-3 willing student volunteers in advance (from younger grades) so the process moves smoothly.

-       Print cue cards: Print the catchphrase card (BELIEVE IT!) and BODY FACT cards for Assistant B to hold up during the show.

 

Sachin Badoni | Chemistry Department | ICSE School Assembly