🥣 Oobleck and cornstarch amount: the whole packet

🥣 Oobleck and cornstarch amount · 3rd–7th grade · 1 day of testing · about $1 · 45 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 cornstarch is mixed in, then how long a penny stays on top of the oobleck will ________________, because _____________________________________________

What I think will happen, in my own words:

3 levels × 3 tries at each = 9 tries in all. If anything you keep the same changes, you won't know which change made the difference.

What I need

• 📦 Cornstarch: about 5 cups
• 🚰 Water from the tap
• 🥛 Clear plastic cups, all the same size: 1
• 🥛 A measuring cup
• 🥄 A spoon
• 🪙 Pennies: 1
• ⏱️ A stopwatch or a kitchen timer
• 🧻 Paper towels

Be safe: 👶 Small parts · 🧽 A bit messy · 🧼 Wash your hands after · 🚫 Test food is not for eating

1. Pour a quarter cup of water into a clear cup.
2. Add a quarter cup of cornstarch and mix for one minute, with a spoon and then your fingers.
3. Lay a penny flat on top of the oobleck as gently as you can, and start the timer.
4. Stop the timer when the penny has sunk out of sight, or at 60 seconds.
5. Write the seconds in your table.
6. Scrape the oobleck into the trash, never down the sink, and wipe the penny dry.
7. Do the same with half a cup of cornstarch, then three quarters of a cup.
8. Do all three amounts two more times, with fresh mixes.
9. Wash your hands, then draw a line graph with cornstarch along the bottom and seconds up the side.

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

I changed: Cornstarch in a quarter cup of water   I measured: how long a penny stays on top of the oobleck (seconds)

MY GRAPH (a line graph: cornstarch in a quarter cup of water along the bottom, seconds 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: stack one, two and three pennies on the best mix, and graph the sinking time against the number of pennies.

1. What made you want to ask this question? Say something like: I wanted to know: how much cornstarch makes oobleck hold a penny?
2. What did you think would happen, and why? Say something like: I thought changing how much cornstarch is mixed in would change how long a penny stays on top of the oobleck, and I wrote down why.
3. What did you change, and what did you measure? Say something like: I changed how much cornstarch is mixed in (A quarter cup, Half a cup, Three quarters of a cup) and measured how long a penny stays on top of the oobleck in seconds.
4. What did you keep the same, and why does that matter? Say something like: I kept a quarter cup of water every time and the same penny, set down as gently as you can the same, so only how much cornstarch is mixed in was different.
5. How many times did you test it? Say something like: 3 times at each of my 3 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 cup and Three quarters of a cup 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: stack one, two and three pennies on the best mix, and graph the sinking time against the number of pennies.