Does hotter water make a bigger cloud in a jar?
- 🔥 Hot
- 💧 Water
My hypothesis
If I change how warm the water in the jar is, then how cloudy the jar gets in one minute will ______, because ______.
You fill in the blanks. Think about what happens to warm, damp air when it meets something cold. A guess is a good because: the test finds out.
Change, measure, keep the same
CHANGE
how warm the water in the jar is: Cold from the fridge, Warm from the tap, Hot, poured by a grown-up
MEASURE
how cloudy the jar gets in one minute, in cloud score, 0 to 5
KEEP THE SAME
- the same jar with the same amount of water
- the same plate of ice cubes on top
- the same dark paper behind the jar
Scientists call the thing you change the independent variable and the thing you measure the dependent variable. The things you keep the same are the controls: if one of them changed too, you wouldn't know which change made the difference. Try each of the 3 levels 3 times.
What you need
- A clear jar or tall glass: 1 big clear glass jar
- Cold water from the fridge
- Warm water
- Hot water from the tap or kettle, for a grown-up to pour: hot from the tap, never boiling
- Ice cubes, all from the same tray: a plateful for each try
- Small plates or saucers, all the same: 1 that sits on the jar's mouth
- Paper: 1 dark sheet
- A measuring cup
- A thermometer (digital, or the red-liquid kind)
- A stopwatch or a kitchen timer
- 🩹 Tape
Steps
- Tape a sheet of dark paper on the wall behind where the jar will stand, so a cloud is easy to see.
- Draw a cloud scale: 0 is clear, 5 is so thick you can't see through it.
- Pour a cup of fridge-cold water into the jar and measure its temperature.
- Set a plate of fresh ice cubes on top of the jar, start the timer and watch.
- After one minute, give the jar a cloud score and write it down.
- Empty and dry the jar, then do it two more times.
- Do three tries with warm tap water the same way.
- Grown-up: A grown-up pours a cup of hot water into the jar and measures its temperature.
- Grown-up: A grown-up sets the plate of ice on top, and you time one minute and score the cloud.
- Grown-up: A grown-up empties the jar, and you do two more hot tries the same way.
- Draw a line graph: water temperature along the bottom, cloud score up the side.
3 steps are a grown-up's, marked above. Write each number down straight away, in the table below, so nothing is lost.
Your results table
Name ______________________ Fair day ____________
Question: Does hotter water make a bigger cloud in a jar?
I changed: Water I measured: how cloudy the jar gets in one minute (cloud score, 0 to 5)
| Water | Try 1 (cloud score, 0 to 5) | Try 2 (cloud score, 0 to 5) | Try 3 (cloud score, 0 to 5) | Mean |
|---|---|---|---|---|
| Cold from the fridge | ||||
| Warm from the tap | ||||
| Hot, poured by a grown-up |
MY GRAPH (a line graph: water along the bottom, cloud score, 0 to 5 up the side)
What I noticed: ______________________________________________
From 4th grade, add the tries for each level and divide by how many there were: that's the mean, and it goes in the last column. Then draw a line graph, because the thing you change is a number that goes up.
Name ______________________ Fair day ____________
Question: Does hotter water make a bigger cloud in a jar?
If I change how warm the water in the jar is, then how cloudy the jar gets in one minute will ________________, because _____________________________________________
| I CHANGE | I MEASURE | I KEEP THE SAME |
|---|---|---|
| Water: Cold from the fridge, Warm from the tap, Hot, poured by a grown-up | how cloudy the jar gets in one minute (cloud score, 0 to 5) |
|
What I think will happen, in my own words:
Name ______________________ Fair day ____________
Question: Does hotter water make a bigger cloud in a jar?
| Date | What I did | What I saw | What I think |
|---|---|---|---|
Name ______________________ Fair day ____________
Question: Does hotter water make a bigger cloud in a jar?
| Date | What I did | What I saw | What I think |
|---|---|---|---|
Name ______________________ Fair day ____________
Question: Does hotter water make a bigger cloud in a jar?
| Date | What I did | What I saw | What I think |
|---|---|---|---|
Name ______________________ Fair day ____________
Question: Does hotter water make a bigger cloud in a jar?
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 hot water with no ice, a few cubes and a full plate of ice, and draw a line for each.
Why it works
Warm water gives off water vapour, an invisible gas, into the air above it. When that damp air meets the cold plate it cools, and the vapour turns back into tiny drops of water, which is how real clouds form high in the sky. Hotter water sends up more vapour, so it usually makes a thicker cloud and more fog on the glass.
Going further (7th and up): Change a second thing: try the hot water with no ice, a few cubes and a full plate of ice, and draw a line for each.
Board layout
- ❓ Question (10 × 8 in): Does hotter water make a bigger cloud in a jar?
- 💭 Hypothesis (10 × 9 in): If I change how warm the water in the jar is, then how cloudy the jar gets in one minute will ______, because ______.
- 🧺 Materials (10 × 12 in): 10 things: see your list.
- 🪜 Steps (22 × 9 in): 11 steps, three tries at each level.
- 📊 Results (22 × 16 in): Your table (Water down the side, tries across) and your line graph.
- ✅ Conclusion (10 × 14 in): My hypothesis was right / partly right / not right. I know because…
Materials to list: A clear jar or tall glass; Cold water from the fridge; Warm water; Hot water from the tap or kettle, for a grown-up to pour; Ice cubes, all from the same tray; Small plates or saucers, all the same; Paper; A measuring cup; A thermometer (digital, or the red-liquid kind); A stopwatch or a kitchen timer.
Bring photos or drawings of your test. Nothing wet, hot, powered or alive on the table.
This project at your grade
| 1st–3rd grade | Tries: three at each level (one is fine at a first fair). The table: levels and tries, numbers or pictures. The graph: a picture, or a simple bar graph. The conclusion: what happened, in their words. |
|---|---|
| 4th–6th grade | Tries: three at each level. The table: units in the header and a mean column. The graph: a bar graph, or a line for a number that grows. The conclusion: right, partly or not, and the numbers that show it. |
| 7th grade and up | Tries: three or more at each level. The table: a mean for every level of both tests. The graph: a graph with two lines or two sets of bars. The conclusion: the numbers, what might have gone wrong, and a next question. Second variable: try the hot water with no ice, a few cubes and a full plate of ice, and draw a line for each. |
From 4th grade up, the table gets a mean column. See every project for 3rd grade, or print a blank results table.
What a judge will ask
- What did you change, and what did you measure? I changed how warm the water in the jar is and measured how cloudy the jar gets in one minute, in cloud score, 0 to 5.
- What did you keep the same, and why does that matter? I kept the same jar with the same amount of water and the same plate of ice cubes on top the same, so the only difference was how warm the water in the jar is.
- How many times did you test it? 3 times at each of my 3 levels.
- If you did it again, what would you change or test next? I'd try the hot water with no ice, a few cubes and a full plate of ice, and draw a line for each.
Make it yours
Keep this project on this device and Peabody counts down to your fair day, with a plan for each day. Nothing is sent anywhere.
Try next
👨👩👧 For grown-ups and teachers: how much to help, the safety rules, and running a school fair. Science fair v0.16.1 · Checked .