Does more baking soda make a bigger fizz?
- 🥽 Goggles on
- 🧽 A bit messy
My hypothesis
If I change how much baking soda goes in, then how high the foam climbs up the cup will ______, because ______.
You fill in the blanks. Think about what the bubbles are made of, and what happens when one of the two runs out. A guess is a good because: the test finds out.
Change, measure, keep the same
CHANGE
how much baking soda goes in: 1 teaspoon, 2 teaspoons, 3 teaspoons
MEASURE
how high the foam climbs up the cup, in cm
KEEP THE SAME
- the same amount of vinegar
- the same cup
- pouring the vinegar in all at once
Scientists call the thing you change the independent variable and the thing you measure the dependent variable. The things you keep the same are the controls: if one of them changed too, you wouldn't know which change made the difference. Try each of the 3 levels 3 times.
What you need
- Baking soda
- White vinegar: about 3 cups in all
- Clear plastic cups, all the same size: 1 tall one
- A measuring cup
- Measuring spoons
- A baking tray or big plate
- A sponge or cloth, for wiping up
- 📏 A ruler
- 🩹 Tape
Steps
- Put your goggles on and stand a tall clear cup on a tray.
- Tape a ruler up the side of the cup, with 0 at the bottom.
- Put 1 teaspoon of baking soda in the cup.
- Pour in a quarter cup of vinegar all at once.
- Watch the ruler and write down the highest the foam reaches.
- Rinse the cup, dry it, and do it two more times.
- Do three tries with 2 teaspoons and three with 3 teaspoons.
- Draw a line graph of baking soda against foam height.
Every step is one you can do yourself, with a grown-up nearby. Write each number down straight away, in the table below, so nothing is lost.
Your results table
Name ______________________ Fair day ____________
Question: Does more baking soda make a bigger fizz?
I changed: Baking soda I measured: how high the foam climbs up the cup (cm)
| Baking soda | Try 1 (cm) | Try 2 (cm) | Try 3 (cm) | Mean |
|---|---|---|---|---|
| 1 teaspoon | ||||
| 2 teaspoons | ||||
| 3 teaspoons |
MY GRAPH (a line graph: baking soda along the bottom, cm up the side)
What I noticed: ______________________________________________
From 4th grade, add the tries for each level and divide by how many there were: that's the mean, and it goes in the last column. Then draw a line graph, because the thing you change is a number that goes up.
Name ______________________ Fair day ____________
Question: Does more baking soda make a bigger fizz?
If I change how much baking soda goes in, then how high the foam climbs up the cup will ________________, because _____________________________________________
| I CHANGE | I MEASURE | I KEEP THE SAME |
|---|---|---|
| Baking soda: 1 teaspoon, 2 teaspoons, 3 teaspoons | how high the foam climbs up the cup (cm) |
|
What I think will happen, in my own words:
Name ______________________ Fair day ____________
Question: Does more baking soda make a bigger fizz?
| Date | What I did | What I saw | What I think |
|---|---|---|---|
Name ______________________ Fair day ____________
Question: Does more baking soda make a bigger fizz?
| Date | What I did | What I saw | What I think |
|---|---|---|---|
Name ______________________ Fair day ____________
Question: Does more baking soda make a bigger fizz?
| Date | What I did | What I saw | What I think |
|---|---|---|---|
Name ______________________ Fair day ____________
Question: Does more baking soda make a bigger fizz?
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: keep 2 teaspoons and try a quarter, a half and a whole cup of vinegar, then find which one runs out first.
Why it works
Baking soda and vinegar react and make a gas called carbon dioxide, and the bubbles of gas make the foam. More baking soda can make more gas, so the foam climbs higher. Once all the vinegar is used up, extra baking soda just sits at the bottom, so the foam stops growing.
Going further (7th and up): Change a second thing: keep 2 teaspoons and try a quarter, a half and a whole cup of vinegar, then find which one runs out first.
Board layout
- ❓ Question (10 × 8 in): Does more baking soda make a bigger fizz?
- 💭 Hypothesis (10 × 9 in): If I change how much baking soda goes in, then how high the foam climbs up the cup will ______, because ______.
- 🧺 Materials (10 × 12 in): 7 things: see your list.
- 🪜 Steps (22 × 9 in): 8 steps, three tries at each level.
- 📊 Results (22 × 16 in): Your table (Baking soda down the side, tries across) and your line graph.
- ✅ Conclusion (10 × 14 in): My hypothesis was right / partly right / not right. I know because…
Materials to list: Baking soda; White vinegar; Clear plastic cups, all the same size; A measuring cup; Measuring spoons; A baking tray or big plate; A sponge or cloth, for wiping up.
Bring photos or drawings of your test. Nothing wet, hot, powered or alive on the table.
This project at your grade
| 1st–3rd grade | Tries: three at each level (one is fine at a first fair). The table: levels and tries, numbers or pictures. The graph: a picture, or a simple bar graph. The conclusion: what happened, in their words. |
|---|---|
| 4th–6th grade | Tries: three at each level. The table: units in the header and a mean column. The graph: a bar graph, or a line for a number that grows. The conclusion: right, partly or not, and the numbers that show it. |
| 7th grade and up | Tries: three or more at each level. The table: a mean for every level of both tests. The graph: a graph with two lines or two sets of bars. The conclusion: the numbers, what might have gone wrong, and a next question. Second variable: keep 2 teaspoons and try a quarter, a half and a whole cup of vinegar, then find which one runs out first. |
From 4th grade up, the table gets a mean column. See every project for 3rd grade, or print a blank results table.
What a judge will ask
- What did you change, and what did you measure? I changed how much baking soda goes in and measured how high the foam climbs up the cup, in cm.
- What did you keep the same, and why does that matter? I kept the same amount of vinegar and the same cup the same, so the only difference was how much baking soda goes in.
- How many times did you test it? 3 times at each of my 3 levels.
- If you did it again, what would you change or test next? I'd keep 2 teaspoons and try a quarter, a half and a whole cup of vinegar, then find which one runs out first.
Make it yours
Keep this project on this device and Peabody counts down to your fair day, with a plan for each day. Nothing is sent anywhere.
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