Day 2 :: June 9
Welcome to Day 2.
Today you're launching rockets in the morning and solving a water park chemistry mystery in the afternoon — using a pH indicator you'll make yourself out of cabbage and water.
Same drill as yesterday. Walk to the corner that matches your answer. 30 seconds in each corner to talk with whoever is there.
- Corner A — Stone State Park or the Loess Hills.
- Corner B — The Sioux City Public Museum or LaunchPAD.
- Corner C — Down to the Missouri River trail or riverfront.
- Corner D — Your favorite restaurant — they need to eat first.
- Corner A — Basketball.
- Corner B — Soccer.
- Corner C — Cross country or track.
- Corner D — None — I'd rather be in the band or theater.
- Corner A — Rebuild it exactly the same way and try again.
- Corner B — Change one thing and test if that fixes it.
- Corner C — Watch what someone else did and copy them.
- Corner D — Scrap it and design something completely new.
Every rocket — from a SpaceX Falcon 9 to your film canister today — works on the same principle: push gas one direction hard enough, and something flies the other way just as hard. That's Newton's Third Law.
- 1 Fuji film canister with snap-on lid
- Alka-Seltzer tablets
- Water
- Safety goggles
- Cardstock and tape (for fins and nose cone)
- What is the job of the Alka-Seltzer tablet?
- What do you think happens if you use more water?
Watch this before your first launch — it shows exactly what to do.
Launch 1 — no modifications:
- Fill the canister about ⅓ full with water.
- Drop in half an Alka-Seltzer tablet.
- Snap the lid on tight.
- Flip it lid-side down on the ground.
- Step back at least 3 feet. Wait.
Count seconds in the air to estimate height: 1 second ≈ 5–6 feet.
Run more launches. Change only one thing at a time so you can compare.
Things to try:
- More water (½ full) or less water (¼ full)
- Whole tablet vs. half tablet
- Add fins — do they make it fly straighter or higher?
- Add a nose cone — does aerodynamics matter at this scale?
Welcome, investigators. The Cool Splash Water Park is having a problem. Visitors are reporting weird smells near Tidal Tremor Bay, a metallic taste at Aqua-Kamikaze, and strange residue at The Abyss Twisters. Something is wrong with the water chemistry — and your team has been called in to figure out what.
Today you'll work like a real chemistry lab. You'll make your own pH indicator from scratch using red cabbage, then go collect water samples and test them two different ways to confirm your findings.
How can we use pH to figure out what is wrong with the water park water?
- Cabbage station — chopped red cabbage and empty zip bags
- Water station — water to add to your cabbage bag
- 6 sample stations — one for each water park location, labeled and ready to pour from
- Walk to the cabbage station. Grab one empty zip bag.
- Scoop a small handful of chopped cabbage into your bag.
- Walk to the water station. Add just enough water to cover the cabbage — not more.
- Squeeze the air out of the bag and seal it tightly.
- Knead the bag for several minutes. Squeeze, mash, press the cabbage with your hands. Take turns at your table — this is real work.
- When the liquid is a deep purple-blue, your indicator is ready. Pour the cabbage juice into a small cup at your table.
- What do you predict this purple liquid will help you discover?
- Why might color be useful in science?
Grab 6 empty vials from your table. Label each vial with the sample location before you pour anything.
- Tidal Tremor Bay
- Serenity Springs
- Aqua-Kamikaze
- Gator Gorge Plunge
- Coral Reef Cove
- The Abyss Twisters
Walk to each of the 6 sample stations. At each one, pour 5–6 ml of the sample into the matching vial. That's about a fingertip's worth — enough to test, not so much you waste it.
Keep your vial numbers matched to the station numbers. Do not mix samples. Bring all 6 filled vials back to your table.
For each of your 6 samples:
- Dip one pH strip into the vial. Pull it out and wait a few seconds.
- Compare the strip color to pH Chart on your handout.
- Decide: is it Acidic, Neutral, or Basic?
For each of your 6 sample vials:
- Add a few drops of cabbage juice to the vial.
- Watch the color change carefully — sometimes it's instant, sometimes it takes a few seconds.
- Compare the new color to pH Chart on your handout.
Flip to Part 2 of your Water Park Mystery handout. Work as a team to answer:
- Which sample has the most extreme pH reading?
- Acidic or basic — and what does that mean for the water park?
- What could be causing the problem at that source?
- What should the water park team do next to protect the affected area?
Each team will share your findings with the class — be ready to back up your answer with both your pH strip data AND your cabbage juice colors.
Chemists classify substances as acids or bases. Lemon juice and vinegar are both acids. Baking soda and many soaps are bases. Some substances, like plain water, are neutral — neither acid nor base.
Red cabbage contains a chemical called anthocyanin. This pigment is a natural acid-base indicator. It's blue in neutral substances. When an acid (like lemon juice) hits it, the molecule changes shape and looks pink. When a base hits it, a different reaction happens and it looks green.
That's why the same purple liquid can give you a different color for every sample — the anthocyanin molecule is literally being reshaped by what's in the water.
- pH — a measure of how acidic or basic something is
- Acid — a substance with a lower pH
- Base — a substance with a higher pH
- Neutral — in the middle of the pH scale
- Indicator — a substance that changes color to give information
- Anthocyanin — the pigment in red cabbage that acts as a pH indicator
- Evidence — observations or data that support an idea
Water quality chemists and environmental engineers test water sources every day — rivers, swimming pools, municipal water supplies, industrial runoff. They use two or more methods to confirm a reading, exactly like you just did. Your red cabbage juice is a low-tech version of the same indicator chemistry in a hospital lab test strip.