💧 Water drops on a penny: the whole packet

💧 Water drops on a penny · 2nd–7th grade · 1 day of testing · free · 30 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 what is in the water, then how many drops fit on the penny before it spills over will ________________, because _____________________________________________

What I think will happen, in my own words:

3 levels × 5 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

• 🪙 Pennies: 1
• 💧 An eyedropper or a medicine dropper
• 🚰 Water from the tap
• 🫧 Dish soap
• 🧂 Salt
• 🥛 Clear plastic cups, all the same size: 3
• 🥛 A measuring cup
• 🥄 Measuring spoons
• 🥄 A spoon
• 🍽️ Small plates or saucers, all the same: 1
• 🧻 Paper towels
• 🩹 Masking tape, to mark lines

Be safe: 👶 Small parts · 🚫 Not food · 💧 Water · 🧼 Wash your hands after

1. Pour a quarter cup of tap water into each of three clear cups.
2. Stir one drop of dish soap into the second cup, and one teaspoon of salt into the third until it disappears.
3. Label the cups plain, soapy and salty.
4. Lay a dry penny flat on a plate, heads up.
5. Squeeze out one drop at a time onto the penny, and count out loud.
6. Stop when water first spills over the edge. Write down the drops you counted before it spilled.
7. Dry the penny with a paper towel, and rinse the dropper in clean water between kinds.
8. Do five tries with each kind of water.
9. Fill in your table, find the mean for each kind, and draw a bar graph.

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

I changed: Water   I measured: how many drops fit on the penny before it spills over (drops)

MY GRAPH (a bar graph: water along the bottom, drops 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: use 1, 2 and 4 drops of dish soap in the cup, and graph the drops that fit against the soap.

1. What made you want to ask this question? Say something like: I wanted to know: how many drops of water fit on a penny?
2. What did you think would happen, and why? Say something like: I thought changing what is in the water would change how many drops fit on the penny before it spills over, and I wrote down why.
3. What did you change, and what did you measure? Say something like: I changed what is in the water (Plain water, Soapy water, Salty water) and measured how many drops fit on the penny before it spills over in drops.
4. What did you keep the same, and why does that matter? Say something like: I kept the same penny, dried between tries and the same dropper, squeezed gently the same, so only what is in the water was different.
5. How many times did you test it? Say something like: 5 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: Plain water and Salty 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: use 1, 2 and 4 drops of dish soap in the cup, and graph the drops that fit against the soap.