Can you turn invisible chemical differences into an ordered rainbow of evidence?
Public beta missionFollow the matching kit materials and the safety guidance on this page. Final production-kit validation is still in progress, so stop and ask a grown-up if your physical setup differs.
2 · Follow the Colour Clues
Your new skill: Read a coarse chart and compare sample colours.
Match the names to your parts before you build. New parts appear when you first need them. You can point, say the name or show a grown-up.
Dropper
A dropper moves a small amount of liquid, one drop at a time.
Spot it and try it
Look for: Find its squeeze bulb and narrow tip.
Before using it: Squeeze before dipping, release to draw liquid, then press gently. Rinse between samples. Never mouth-pipette. Drop size can vary.
Your turn: Practise three separate drops of clean water into a tray.
Test tube and stand
A tube holds a small sample. The stand helps keep tubes upright while we compare them.
Spot it and try it
Look for: Find the narrow containers and matching holes in the stand.
Before using it: Label samples before filling. Keep them open and stable; never seal a fizzing reaction.
Your turn: Place two empty tubes in the stand and label them A and B.
Calibrated kit measuring spoon
This spoon measures a repeatable amount of powder so our comparisons use the same amount.
Spot it and try it
Look for: Find the kit's supplied measure and its labelled amount. A level spoon is flat across the top.
Before using it: Use the approved kit measure, not a random kitchen spoon. Powder amount and spoon size must match the kit batch instructions.
Your turn: Show the difference between level and heaped using an empty spoon and a drawing.
Mixing stick
A mixing stick moves liquid and powder together so we can compare how mixing affects a result.
Spot it and try it
Look for: Find the clean stirrer named in the materials.
Before using it: Use a clean stick for each sample, or rinse and dry between samples. Never taste it.
Your turn: Rehearse a gentle stir in an empty container without splashing.
Citric acid
Citric acid is our labelled acidic material. Dissolved in water it can change an indicator's colour and react with baking soda.
Spot it and try it
Look for: Find the sealed container with its correct label. Similar-looking powders are not interchangeable.
Before using it: Use only the stated amount, goggles and adult supervision. Experiment materials are not food. Keep away from eyes and mouth.
Your turn: Read the label with a grown-up before opening it.
Baking soda
Baking soda is our labelled mild base. With citric acid and water, the reaction releases carbon dioxide gas.
Spot it and try it
Look for: Find the container labelled baking soda, not baking powder.
Before using it: Use only the stated amount with adult supervision. Never close a fizzing mixture in a sealed container.
Your turn: Predict where bubbles can escape safely in the open experiment.
Litmus and pH paper
These papers give colour clues about acidity. Litmus tells us acid or base clues; pH paper is compared with its matching colour chart.
Spot it and try it
Look for: Find red or blue litmus, or pH strips with their supplied chart. They are not interchangeable.
Before using it: Use a fresh piece for each sample and read at the stated time. A colour estimate is not an exact laboratory pH or a food safety test.
Your turn: Match an unused strip to its packet and chart.
Dish soap New here
A little dish soap changes how the surface of water behaves and can help trap bubbles as foam.
Spot it and try it
Look for: Use ordinary dish soap named by the mission, from home.
Before using it: Use tiny amounts only, keep away from eyes and do not substitute bleach or cleaning chemicals.
Your turn: Predict whether plain water and soapy water will behave the same.
Tray cup and dry workspace
A tray catches spills, cups hold samples or form a model, and a dry workspace protects our tools.
Spot it and try it
Look for: Choose the exact container and dry surface in the mission list.
Before using it: Experiment cups stay separate from food and drinks. Keep electronics away from liquids and clean up before storing parts.
Your turn: Show where a spill would land and where electrical parts will stay dry.
Meet the parts for Build a pH Rainbow
A video demonstration will appear here when it is ready. You can follow the written step now.
Read the video instructions
Before we build, match these names to the parts in front of you. Dropper. A dropper moves a small amount of liquid, one drop at a time. Find its squeeze bulb and narrow tip. Squeeze before dipping, release to draw liquid, then press gently. Rinse between samples. Never mouth-pipette. Drop size can vary. Test tube and stand. A tube holds a small sample. The stand helps keep tubes upright while we compare them. Find the narrow containers and matching holes in the stand. Label samples before filling. Keep them open and stable; never seal a fizzing reaction. Calibrated kit measuring spoon. This spoon measures a repeatable amount of powder so our comparisons use the same amount. Find the kit's supplied measure and its labelled amount. A level spoon is flat across the top. Use the approved kit measure, not a random kitchen spoon. Powder amount and spoon size must match the kit batch instructions. Mixing stick. A mixing stick moves liquid and powder together so we can compare how mixing affects a result. Find the clean stirrer named in the materials. Use a clean stick for each sample, or rinse and dry between samples. Never taste it. Citric acid. Citric acid is our labelled acidic material. Dissolved in water it can change an indicator's colour and react with baking soda. Find the sealed container with its correct label. Similar-looking powders are not interchangeable. Use only the stated amount, goggles and adult supervision. Experiment materials are not food. Keep away from eyes and mouth. Baking soda. Baking soda is our labelled mild base. With citric acid and water, the reaction releases carbon dioxide gas. Find the container labelled baking soda, not baking powder. Use only the stated amount with adult supervision. Never close a fizzing mixture in a sealed container. Litmus and pH paper. These papers give colour clues about acidity. Litmus tells us acid or base clues; pH paper is compared with its matching colour chart. Find red or blue litmus, or pH strips with their supplied chart. They are not interchangeable. Use a fresh piece for each sample and read at the stated time. A colour estimate is not an exact laboratory pH or a food safety test. Dish soap. A little dish soap changes how the surface of water behaves and can help trap bubbles as foam. Use ordinary dish soap named by the mission, from home. Use tiny amounts only, keep away from eyes and do not substitute bleach or cleaning chemicals. Tray cup and dry workspace. A tray catches spills, cups hold samples or form a model, and a dry workspace protects our tools. Choose the exact container and dry surface in the mission list. Experiment cups stay separate from food and drinks. Keep electronics away from liquids and clean up before storing parts. Pause and point to the part that will do the main job in this mission. If it is missing or looks different, ask a grown-up before building.
WHAT YOU'LL USE
Match these to your kit
Four tubes and standAcid sample: 10 mL water + 1/4 measure citric acidCitric acidBase sample: 10 mL water + 1/4 measure baking sodaBaking sodaMixing stickpH paper and supplied colour chartDropper
Gather from home
Neutral sample: 10 mL waterSoap sample: 10 mL water + 2 drops dish soapDish soapClean waterRinsing cup
Kit list: match the named parts to your box and its component cards. Home list: gather these before starting; some may also be supplied in your kit. Reuse components between missions. Stop and ask a grown-up if an essential part or label is missing.
BEFORE YOU BUILD
Wear goggles. Keep the samples labelled and never taste them. pH colour depends on the exact paper brand, so use the supplied chart.
YOUR REWARD
+50 XPMission completion
PREDICT BEFORE YOU BEGIN
Where will the soap sample sit compared with baking soda solution? Mark your guess before testing.
YOUR CHALLENGE
Test four samples and arrange their results in a sensible pH order.
NEW POWER-UP
Read a coarse chart and compare sample colours.
You have just practised identify known acid, water and base samples from evidence. Now: read a coarse chart and compare sample colours.
Adult help: Required
Open diagrams and build references
BUILD PATH
STEP 1 OF 8
Label four tubes ACID, WATER, BASE and SOAP
Try · Notice · ExplainRead the checkpoint, make a prediction, then test your idea.
Label four tubes ACID, WATER, BASE and SOAP.
Build a pH Rainbow — Step 1
A video demonstration will appear here when it is ready. You can follow the written step now.
Read the video instructions
Label four tubes ACID, WATER, BASE and SOAP.
Need a diagram for this step?
WHAT'S REALLY HAPPENING?
Why it works
The pH scale helps compare how acidic or basic a water-based solution is. Lower pH values are more acidic, pH 7 is neutral, and higher values are more basic. Indicator colours are approximate, so scientists compare carefully rather than pretending the strip is a perfect digital meter.
pH testing is used in water care, agriculture, food science and environmental monitoring.
FAIR-TEST CHALLENGE
Prepare a second acid sample with twice as much water but the same citric acid. Test it beside the first sample.
WHEN IT DOESN'T WORK YET
Check the evidence before changing the setup.
WHAT YOU SEE
LIKELY REASON
TRY THIS FIRST The strip colour does not match the poster exactly Lighting, timing or paper batches can change appearance.
Use only the chart supplied with that paper and record an approximate range.
Samples are mixed up Labels were added too late.
Discard the samples and label empty tubes before mixing again.
Water appears strongly acidic or basic The tools may contain residue.
Wash, rinse and dry everything, then retest fresh water.
CLEAN, RESET AND STORE
Pour the samples down the sink with plenty of water. Discard strips. Rinse and dry all tubes and tools.
NEXT SKILL
Keep transfers equal and recognise indicator limits.