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?

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

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.

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

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

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.

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

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.

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

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