🧂 Salt and ice water temperature: the whole packet

🧂 Salt and ice water temperature · 3rd–8th grade · 1 day of testing · free · 60 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 salt goes in the ice water, then how cold the ice water gets after 10 minutes 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

• 🧊 Ice cubes, all from the same tray: about 24 cubes for each round
• 🥛 Clear plastic cups, all the same size: 4, the same size
• 🧊 Cold water from the fridge: half a cup for each cup
• 🥛 A measuring cup
• 🧂 Salt: 6 tablespoons for each round
• 🥄 Measuring spoons
• 🥄 A spoon
• 🌡️ A thermometer (digital, or the red-liquid kind)
• ⏱️ A stopwatch or a kitchen timer
• 🩹 Masking tape, to mark lines
• 🧽 A sponge or cloth, for wiping up

Be safe: 💧 Water · 🚫 Test food is not for eating

1. Label four cups with tape: no salt, 1, 2 and 3 tablespoons.
2. Put six ice cubes in each cup, then half a cup of cold water.
3. Read the thermometer in the no-salt cup and write it down: that is your starting number.
4. Add the salt each label says, then start the timer.
5. Stir each cup ten times every two minutes, the same way each time.
6. At 10 minutes, hold the thermometer in each cup for 30 seconds, then read it.
7. Write each cup's temperature in your table, rinsing the thermometer between cups.
8. Pour everything away, dry the cups, and do it twice more with fresh ice.
9. Draw a line graph: salt along the bottom, temperature up the side.

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

I changed: Salt   I measured: how cold the ice water gets after 10 minutes (degrees)

MY GRAPH (a line graph: salt along the bottom, degrees 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: try the same amounts of salt in cups packed with crushed ice, and graph both lines on one chart.

1. What made you want to ask this question? Say something like: I wanted to know: does more salt make ice water colder?
2. What did you think would happen, and why? Say something like: I thought changing how much salt goes in the ice water would change how cold the ice water gets after 10 minutes, and I wrote down why.
3. What did you change, and what did you measure? Say something like: I changed how much salt goes in the ice water (No salt, 1 tablespoon, 2 tablespoons, 3 tablespoons) and measured how cold the ice water gets after 10 minutes in degrees.
4. What did you keep the same, and why does that matter? Say something like: I kept the same number of ice cubes in every cup and the same amount of cold water in every cup the same, so only how much salt goes in the ice water 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: No salt and 3 tablespoons 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: try the same amounts of salt in cups packed with crushed ice, and graph both lines on one chart.