🥬 Red cabbage colour test: the whole packet

🥬 Red cabbage colour test · 4th–8th grade · 1 day of testing · about $3 · 60 minutes a sitting

My days, if the fair is 14 days away

Count back from your fair day and write in each date. Fewer days than this? The jobs share days, in this order; nothing is skipped.

Dates from my teacher

• My question is due
• Testing starts
• My results table and graph are due
• My board is due

In this packet

1. 🗓️ My project plan
2. 💭 My hypothesis
3. 🧺 Change, measure, keep the same
4. 🪜 My steps
5. 📊 My results
6. 📓 My logbook
7. ✅ My conclusion
8. ✂️ Board titles to cut out
9. 🏅 The judge's questions and my certificate

If I change the liquid added to the cabbage water, then what colour the cabbage water turns, on your 1 to 5 scale will ________________, because _____________________________________________

What I think will happen, in my own words:

5 levels × 3 tries at each = 15 tries in all. If anything you keep the same changes, you won't know which change made the difference.

What I need

• 🥬 A quarter of a red cabbage: a quarter of one
• ♨️ Hot water from the tap or kettle, for a grown-up to pour: 2 cups, hot from the tap, never boiling
• 🥣 A big bowl
• 🔻 A kitchen funnel
• ⚪ Round paper coffee filters: 1
• 🫙 A clear jar or tall glass: 1, to hold the cabbage water
• 🍶 White vinegar
• 🍋 Lemon juice
• 🚰 Water from the tap
• 🫧 Dish soap
• 🧂 Baking soda
• 🥛 Clear plastic cups, all the same size: 5
• 🥛 A measuring cup
• 🥄 Measuring spoons
• 🥄 A spoon
• 📄 Paper
• 🖍️ Crayons or markers
• 🔪 A sharp kitchen knife, for the grown-up

Be safe: ✂️ Sharp · 🔥 Hot · 🚫 Not food · 🥽 Goggles on · 🧽 A bit messy · 🚫 Test food is not for eating

1. Grown-up: A grown-up chops the red cabbage into small pieces.
2. Grown-up: A grown-up puts the pieces in a bowl and pours hot water over them.
3. Wait twenty minutes, until the water turns deep purple.
4. Grown-up: A grown-up pours the purple water through a coffee filter in a funnel into a jar.
5. Let the purple water cool down before you touch it, and put your goggles on.
6. Colour a row of five squares: 1 pink, 2 pink-purple, 3 purple, 4 blue and 5 green.
7. Mix baking soda water (a teaspoon in a quarter cup) and soapy water (3 drops of soap in a quarter cup).
8. Pour a quarter cup of cool purple water into each of five clear cups.
9. Stir a tablespoon of a different liquid into each cup. Never drink any of them.
10. Compare each cup with your colour squares, and write its colour number in your table.
11. Pour out, rinse the cups, and do the whole test two more times.
12. Find the mean colour number for each liquid, and draw a bar graph.

Write each number in your results table the moment you measure it.

I changed: Liquid added   I measured: what colour the cabbage water turns, on your 1 to 5 scale (colour number, 1 to 5)

MY GRAPH (a bar graph: liquid added along the bottom, colour number, 1 to 5 up the side)

What I noticed: ______________________________________________

Write something every day you work on it, even the days you only gather things. More days? The three-page logbook prints from peabody.kids/science-fair/templates/logbook.

My hypothesis was ☐ right ☐ partly right ☐ not right.

I know because my numbers show:

What surprised me, or what might have gone wrong (7th and up):

Next time I would test:

Idea: Change a second thing: mix vinegar and baking soda water in steps, a teaspoon at a time, and graph the colour number against the amount of each.

1. What made you want to ask this question? Say something like: I wanted to know: which kitchen liquids change red cabbage water?
2. What did you think would happen, and why? Say something like: I thought changing the liquid added to the cabbage water would change what colour the cabbage water turns, on your 1 to 5 scale, and I wrote down why.
3. What did you change, and what did you measure? Say something like: I changed the liquid added to the cabbage water (Vinegar, Lemon juice, Plain water, Soapy water, Baking soda water) and measured what colour the cabbage water turns, on your 1 to 5 scale in colour number, 1 to 5.
4. What did you keep the same, and why does that matter? Say something like: I kept a quarter cup of the same cabbage water in every cup and one tablespoon of each liquid the same, so only the liquid added to the cabbage water was different.
5. How many times did you test it? Say something like: 3 times at each of my 5 levels, and I found the middle number.
6. What did you find out? Show me in your numbers. Say something like: Look at my table: Vinegar and Baking soda water gave different numbers, and here's the pattern.
7. Was your hypothesis right? How do you know? Say something like: My numbers show whether I was right, partly right or not, and I can show you where.
8. Did anything go wrong, or surprise you? Say something like: One try was odd, so I did it again and wrote it in my logbook.
9. If you did it again, what would you change or test next? Say something like: I'd change a second thing: mix vinegar and baking soda water in steps, a teaspoon at a time, and graph the colour number against the amount of each.