Prerequisite bridge, model and guided practice

Read before comparing

Target: Read temperature and change accurately before explaining a result. Prerequisites: read a small table, subtract whole numbers and recognize °C. Warming means final temperature is higher; cooling means it is lower. Check the same row and time interval.

Two 100 g water samples in a 22°C room; matching cups, lids and reading method. W and Z are sample names.

Water readings at start and 10 minutes

Constructed teaching data: these values were invented for this activity, not collected in an experiment.

Sample	Start (°C)	After 10 min (°C)
W	11	15
Z	11	13

1. What quantity and unit are recorded? What interval is compared?

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2. How much did each sample change? Did it warm or cool?

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Trace start → final. For cooling, find how far the temperature fell. You may use a number line or answer aloud.

Read the whole record

Question: Which sample warmed less during these 15 minutes? Read one complete column before comparing samples.

X and Y each contain 100 g water starting at 10°C in a 22°C room. Cups, lids, measurement method and exposure match. This is one illustrative trial of two complete setups.

Water temperatures over time

Constructed teaching data: these values were invented for this activity, not collected in an experiment.

Time (min)	Sample X (°C)	Sample Y (°C)
0	10	10
5	13	11
10	15	12
15	17	13

1. Name the measured quantity and units. Give two observations without a cause.

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2. Calculate each 0-to-15-minute change. Which sample warmed less?

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3. Is “Y became cooler” accurate? What can this record tell us, and what cannot it explain?

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A final value is a reading. A change compares the start and finish for that sample. The next page shows the same record as a graph.

The same record as a graph

Data M again · Same 100 g samples, 10°C start, 22°C room, matching cups/lids, method and 15-minute exposure. This graph repeats the model record; it is not a second trial.

Equal-interval time axis 0, 5, 10, 15 min; temperature axis 10–18°C. Solid line with square points: X = 10, 13, 15, 17°C. Dashed line with circle points: Y = 10, 11, 12, 13°C. The text table on the previous page is equivalent.

Constructed teaching data: these values were invented for this activity, not collected in an experiment.

Equal-interval time axis 0, 5, 10, 15 min; temperature axis 10–18°C. Solid line with square points: X = 10, 13, 15, 17°C. Dashed line with circle points: Y = 10, 11, 12, 13°C. The text table on the previous page is equivalent.

1. Read X at 10 minutes and Y at 15 minutes. Identify each axis and its unit.

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2. Does the graph provide new measurements? Explain how its time spacing matches the table.

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You may use the model table instead of the graph. Drawing a graph is not required to show the science.

Guided practice · Cooling

K and L each contain 100 g water starting at 32°C in a 22°C room. Cups, lids, 15-minute exposure and reading method match; two complete setups, one trial. This is a paper task.

Warm water readings over time

Constructed teaching data: these values were invented for this activity, not collected in an experiment.

Time (min)	Sample K (°C)	Sample L (°C)
0	32	32
5	29	30
10	27	29
15	25	28

1. Compare start and finish for K and L. State direction and size of each change.

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2. Which setup shows less cooling? Why would choosing the lowest final value miss this goal?

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3. Which statement is an observation: “K is 25°C at 15 minutes” or “K loses energy only by conduction”? Explain.

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