🫧 Soap amount and bubble size: the whole packet

🫧 Soap amount and bubble size · 1st–5th grade · 1 day of testing · free · 40 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 how much soap is in the bubble mix, then how wide the ring is that the bubble leaves will ________________, because _____________________________________________

What I think will happen, in my own words:

4 levels × 3 tries at each = 12 tries in all. If anything you keep the same changes, you won't know which change made the difference.

What I need

• 🫧 Dish soap
• 🚰 Water from the tap
• 🥛 Clear plastic cups, all the same size: 4
• 🥛 A measuring cup
• 🥄 Measuring spoons
• 🥄 A spoon
• 🥤 Straws: 4
• 🍽️ A baking tray or big plate
• 🧽 A sponge or cloth, for wiping up
• 🩹 Masking tape, to mark lines
• 📏 A ruler

Be safe: 🚫 Not food · 💧 Water · ⚠️ Soapy floors are slippery: wipe up · 🧼 Wash your hands after

1. Pour half a cup of tap water into each of four clear cups.
2. Stir in dish soap slowly, so no foam forms: a quarter teaspoon, 1 teaspoon, 2 teaspoons and 1 tablespoon.
3. Label each cup with the amount of soap in it.
4. Spread a spoonful of the first mix over a tray to make a wet patch.
5. Dip the end of a straw in the first mix and touch it to the wet patch.
6. Blow out slowly, and never suck in through the straw.
7. Keep blowing slowly until the bubble pops and leaves a ring of tiny drops.
8. Measure straight across the ring, and write the cm in your table.
9. Wipe the tray, use a new straw for each mix, and make three bubbles with each mix.
10. Draw a line graph: soap along the bottom, ring width up the side.

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

I changed: Soap in half a cup of water   I measured: how wide the ring is that the bubble leaves (cm)

MY GRAPH (a line graph: soap in half a cup of water along the bottom, cm 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: stir 1 teaspoon of corn syrup into the best mix, and graph the ring widths with and without it.

1. What made you want to ask this question? Say something like: I wanted to know: how much soap makes the biggest bubble?
2. What did you think would happen, and why? Say something like: I thought changing how much soap is in the bubble mix would change how wide the ring is that the bubble leaves, and I wrote down why.
3. What did you change, and what did you measure? Say something like: I changed how much soap is in the bubble mix (A quarter teaspoon, 1 teaspoon, 2 teaspoons, 1 tablespoon) and measured how wide the ring is that the bubble leaves in cm.
4. What did you keep the same, and why does that matter? Say something like: I kept half a cup of the same tap water in every mix and the same dish soap and the same straw for each mix the same, so only how much soap is in the bubble mix was different.
5. How many times did you test it? Say something like: 3 times at each of my 4 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: A quarter teaspoon and 1 tablespoon 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: stir 1 teaspoon of corn syrup into the best mix, and graph the ring widths with and without it.