🪙 Cleaning dull pennies: the whole packet

🪙 Cleaning dull pennies · 2nd–6th 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 the liquid the pennies soak in, then how many of the five pennies look shiny 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

• 🪙 Pennies: 60 dull ones, all about as dirty
• 🍶 White vinegar
• 🧂 Salt
• 🍋 Lemon juice
• 🚰 Water from the tap
• 🫧 Dish soap
• 🥛 Clear plastic cups, all the same size: 4
• 🥛 A measuring cup
• 🥄 Measuring spoons
• 🥄 A spoon
• 🧻 Paper towels
• ⏱️ A stopwatch or a kitchen timer
• 🩹 Masking tape, to mark lines

Be safe: 👶 Small parts · 🚫 Not food · 🧼 Wash your hands after · 🚫 Test food is not for eating

1. Label four clear cups with tape: vinegar and salt, lemon juice, plain water and soapy water.
2. Stir one teaspoon of salt into a quarter cup of vinegar in the first cup.
3. Pour a quarter cup of lemon juice into the second cup and a quarter cup of tap water into the third.
4. Stir one drop of dish soap into a quarter cup of tap water in the fourth cup.
5. Slide five dull pennies into each cup, and start the timer for ten minutes.
6. Lift the pennies out with a spoon and lay them on a paper towel.
7. Count the pennies that look shiny all over. Any brown left means not shiny.
8. Write the count for each cup in your table.
9. Do the whole test two more times, with fresh liquids and new dull pennies.
10. Wash your hands, and never drink the liquids.
11. Find the mean for each liquid, and draw a bar graph.

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

I changed: Liquid   I measured: how many of the five pennies look shiny (pennies shiny, of 5)

MY GRAPH (a bar graph: liquid along the bottom, pennies shiny, of 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: soak pennies in the best liquid for 2, 5 and 10 minutes, and draw a line of shiny pennies against time.

1. What made you want to ask this question? Say something like: I wanted to know: which kitchen liquid cleans an old penny best?
2. What did you think would happen, and why? Say something like: I thought changing the liquid the pennies soak in would change how many of the five pennies look shiny, and I wrote down why.
3. What did you change, and what did you measure? Say something like: I changed the liquid the pennies soak in (Vinegar with salt, Lemon juice, Plain water, Soapy water) and measured how many of the five pennies look shiny in pennies shiny, of 5.
4. What did you keep the same, and why does that matter? Say something like: I kept pennies that are all about as dull and a quarter cup of liquid in every cup the same, so only the liquid the pennies soak in 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: Vinegar with salt and Soapy 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: soak pennies in the best liquid for 2, 5 and 10 minutes, and draw a line of shiny pennies against time.