Lab / experiment Grade 2 Engineering & Design
Ashfield's Cold Pipe Wrap: A Grade 2 Insulation Test
A two-session grade 2 investigation comparing a paper towel wrap and a felt wrap on cups of ice, then refreezing the melted water to show the change reverses.
Objectives
- Students will describe two wrap materials by observable properties before testing them.
- Students will compare melted water and cubes left for an unwrapped cup and two wrapped cups.
- Students will use refrozen water as evidence that melting is a change that can be reversed.
Vocabulary
Key words: wrap, melt, freeze, thick, compare
Teacher overview
Winter crews in the town of Ashfield wrap the water pipes that run along the outside of the school so the water inside does not freeze and split them open. A classroom cannot freeze a pipe safely, so this investigation runs the test the other way around: cups of ice stand in for cold pipes, and students compare which wrap keeps the ice solid longest in a warm room. A wrap that slows warmth moving into the ice is the same wrap that slows warmth moving out of the water in a pipe, which is the connection to make explicit during the debrief. The second session takes fifteen minutes the following day, when the class refreezes the melted water and treats the result as evidence that melting can be undone.
Procedure
Read aloud with the class before starting: "Pipes outside can get very cold. Crews wrap them to keep them safe. Today we will test two wraps." Remind students not to drink any of the water.
Step 1. Look at the felt and the paper towel. Feel each one. Write one word for each. Is it thick or thin? Is it soft or smooth?
Step 2. Put 6 ice cubes in each of the three cups. Use cubes that are the same size.
Step 3. Cup A gets no wrap at all. Cup B gets a paper towel wrap. Cup C gets a felt wrap. Hold each wrap on with a rubber band.
Step 4. Write down your guess. Which cup will have the most melted water?
Step 5. Set all three cups on the tray. Put the tray in one warm spot in the room.
Step 6. Wait 30 minutes. Do not touch the cups while you wait.
Step 7. Take the wraps off. Pour the melted water from Cup A into the measuring cup. Read the ounces. Write the number in the table. Wipe up spills right away.
Step 8. Do the same for Cup B and Cup C. Empty the measuring cup into a clean tray each time.
Step 9. Count the ice cubes left in each cup. Write each count in the table.
Step 10. Put the clean tray of melted water in a freezer overnight. Look at it the next day and write what you see.
Data & Analysis
| Cup | Wrap | Melted water (ounces) | Cubes left |
|---|---|---|---|
| A | none | ||
| B | paper towel | ||
| C | felt |
- Which cup had the most melted water?
- Which wrap kept the most ice cubes solid?
- Suppose a group started with 6 cubes and found 2 cubes left in Cup A. How many cubes melted?
- Which wrap is thicker, the paper towel or the felt? Tell how that helped.
- Crews in Ashfield wrap the pipes outside in winter. Use your data to tell why a wrap helps.
- You put the melted water in the freezer. What happened to it? Can melting be undone?
From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.
Answer Key
- Answer: Accept the cup that matches the group's own recorded numbers. Most groups find Cup A, the unwrapped cup, has the most melted water because nothing slows the room's warmth from reaching the ice.
- Answer: Accept the wrap that matches the group's own cube counts. Most groups find Cup C, the felt wrap, leaves the most cubes solid, with the paper towel second and no wrap last.
- Answer: 4 cubes. Subtract the cubes left from the cubes at the start: 6 - 2 = 4.
- Answer: The felt. Accept any answer noting that the felt is thicker, fuzzier, or holds more air, and that a thicker wrap slows the warmth reaching the ice.
- Answer: Accept any answer that cites the group's own numbers and connects them to the pipe, such as noting the felt cup kept more cubes solid, so a thick wrap keeps a pipe near its own temperature longer when the air outside changes.
- Answer: It froze back into ice. Melting can be undone, because cooling the water turned it solid again. Accept "it turned to ice again" or "yes, we froze it back."
Differentiation
Support
Run Cup A and Cup C only for these groups so the comparison is between two setups rather than three, and mark the measuring cup with a colored band at each whole ounce so readings are matched to a mark rather than read from small print. Read the analysis questions aloud and accept spoken answers recorded by an adult.
Extension
Ask these groups to add a fourth cup wrapped in aluminum foil, predict in writing where its result will fall against the paper towel and the felt, and then explain whether the prediction held. Have them name the one property of the wrap they think matters most and give evidence from their table.
ELL supports
Pre-teach wrap, melt, freeze, thick, and thin by passing the felt and the paper towel around while naming each word and its opposite. Provide the frames "Cup ___ had more water" and "The ___ wrap worked better," and let students record their observations as drawings with number labels.
Extensions
Take the class outside on a cold day to find any wrapped pipe or spigot cover on the school building and compare its covering with the materials tested indoors. Groups can then design a cover for the outdoor spigot nearest the playground, sketch it from the side, and label the material they would use and why.