Temperature and its Measurement — Measure and Compare Data (3 of 3) · Learner pages

Lesson 1 · Plan a correct water measurement

Explain the placement and reading steps for a suitable laboratory thermometer in water.

Name or initials: ____________   Date: ____________

The reading depends on how the instrument is used. Study the supplied diagram or a teacher-approved demonstration with an appropriate instrument. This lesson needs no heating, boiling water or glass handling by learners.

1. Check the setup. Use the supplied diagram or a teacher-managed setup. The illustrated liquid-in-glass instrument is upright and its sensitive bulb is in the water. A different instrument may have a different immersion requirement, so its instructions take priority.
2. Keep clear of the container. The model bulb is below the water surface, away from the bottom and sides. Contact with the container can affect what is being measured. Do not hold a thermometer by its bulb; avoid warming its sensitive part with a hand.
3. Wait and view at the correct level. For this illustrated instrument, wait for the column to settle and read its top at eye level while the bulb remains immersed. Removing it changes its surroundings, so its reading can change toward the air temperature.
4. Record a meaningful observation. Record sample, value, unit and time, plus any relevant instrument detail or unusual condition. If the sample is changing temperature, note that the readings describe different times; do not assume every difference is a mistake.

Worked example: In a supplied demonstration, a water sample reads 28 °C while the bulb is immersed. After the instrument is removed into a cooler room, the column begins to fall. The later value is not a preserved reading of the original water; the sensor’s surroundings have changed.

1. For the illustrated liquid-in-glass water measurement, the bulb should be…

   1. Immersed and clear of the container’s sides and bottom · 2. Pressed against the beaker bottom · 3. Held above the water throughout

2. Where should the eye be when reading the illustrated column?

   1. Far above the column looking down · 2. Level only with the water surface regardless of the column · 3. Level with the top of the liquid column

3. Why read this laboratory thermometer while it remains immersed?

   1. Removing it always doubles the temperature · 2. Its reading can change when moved into different surroundings · 3. Every thermometer stores every reading forever

Discuss: Annotate the supplied diagram with upright placement, submerged bulb, clearance from the container and eye-level reading. Explain one effect of removing the instrument before reading.

Explain or demonstrate

Annotate the supplied model with four correct placement or reading features. Explain why a reading taken after removal can differ.

Evidence to include:

• Upright placement
• Bulb immersed without side or bottom contact
• Eye at column top and reading taken while immersed

Lesson 2 · Investigate different readings

Compare recorded temperatures and explain what agreement and disagreement can establish.

Name or initials: ____________   Date: ____________

Measurement records can differ for several reasons: conditions, instrument detail, timing or reading method. Preserve the observations and investigate before deciding which explanation is supported.

1. Keep the observations. The model supplies three readings for an intended stable sample: 28.0 °C, 28.5 °C and 28.0 °C. Record all three. Do not silently change a reading just because two others agree.
2. Describe the difference. The largest reading is 28.5 °C and the smallest is 28.0 °C. The spread is 0.5 °C. Describing the spread is different from knowing its cause. The middle reading is not automatically dishonest or wrong.
3. Check plausible causes. Check whether everyone read at eye level, waited for stability and used the same placement, scale and time. Compare the instrument’s divisions with the reported digits. Repeating a careful reading can help test an explanation, but does not guarantee a particular result.
4. Avoid overclaiming. Matching readings support consistency, but an incorrectly used or faulty instrument can give matching results. A constant reading can also be real: supplied records for pure ice melting or water boiling under steady pressure can show a plateau. Do not perform a heating experiment for this lesson.

Worked example: A supplied record for one steady melting ice-water mixture is 0.0 °C, 0.0 °C and 0.0 °C at ordinary atmospheric pressure. The repeated value can be consistent with melting, not necessarily a stuck instrument. A separate instrument check is needed to decide whether it works correctly; the record alone cannot settle that.

1. What is the spread of 28.0 °C, 28.5 °C and 28.0 °C?

   1. 28.5 °C · 2. 84.5 °C · 3. 0.5 °C

2. Two readings agree and one differs. What is the most careful response?

   1. Accuse that observer of dishonesty · 2. Keep all records and investigate conditions and method · 3. Delete the different reading without comment

3. Which could affect a scale reading?

   1. Viewing from above instead of eye level · 2. The observer’s name having more letters · 3. The notebook cover colour

Discuss: For 21.0 °C, 21.5 °C and 21.0 °C readings of an intended stable sample, calculate the spread, name two possible causes and propose one fair repeat check. Keep the original data.

Explain or demonstrate

For supplied readings 21.0, 21.5 and 21.0 °C, state the spread, two plausible explanations and one repeat check. Explain why agreement would not prove accuracy.

Evidence to include:

• Spread calculated
• Possible causes treated as hypotheses
• Repeat method controlled

Lesson 3 · Interpret daily air-temperature data

Read maximum and minimum temperatures, calculate daily differences and limit conclusions to the data.

Name or initials: ____________   Date: ____________

Weather records report air temperature for a place and time. A daily maximum is the highest recorded value for that day and a daily minimum is the lowest. These are different from a single room-thermometer reading.

1. Identify the dataset. The graph is invented for learning, not a live weather report. For days D1 to D5, maxima are 30, 32, 31, 29 and 33 °C; minima are 20, 21, 19, 18 and 22 °C. A real record also needs dates, place and source.
2. Read the paired values. Use the legend and match both points to the same day. On D3 the maximum is 31 °C and the minimum is 19 °C. Do not accidentally pair the maximum from one day with the minimum from another.
3. Calculate a daily range. For D3, daily range = 31 − 19 = 12 °C. The other daily ranges are 10, 11, 11 and 11 °C for D1, D2, D4 and D5. The day with the highest maximum need not have the widest daily range.
4. State what the record can show. D5 has the highest maximum here; D3 has the widest daily range. Five invented days do not establish a certain seasonal trend or a weather forecast. For a real project, collect and attribute successive daily records and include any missing observations.

Worked example: For D2, 32 − 21 = 11 °C. For D3, 31 − 19 = 12 °C. D3 has a wider daily range even though its maximum is lower. D5 has the highest maximum, 33 °C, but its range is 33 − 22 = 11 °C.

1. For D3, maximum 31 °C and minimum 19 °C give a daily range of…

   1. 19 °C · 2. 12 °C · 3. 50 °C

2. In the supplied data, which day has the highest maximum: D1 30, D2 32, D3 31, D4 29, D5 33 °C?

   1. D5 · 2. D2 · 3. D4

3. Which pair should be used for one daily range?

   1. Any maximum and any minimum from different days · 2. A temperature and a volume · 3. The maximum and minimum for the same day and place

Discuss: Create a table from the five invented days with maximum, minimum and calculated range. Write two supported comparisons and one forecast claim that the data cannot justify. A later real-weather project can extend to ten attributed successive days.

Explain or demonstrate

Using maxima [30,32,31,29,33] °C and minima [20,21,19,18,22] °C for D1–D5, tabulate all five daily ranges and make two supported comparisons. Label the data as invented.

Evidence to include:

• Correct pairs used
• Five ranges calculated
• Comparisons limited to the supplied days

Final check · Set 1

Try one set after the lessons. Use the other set after reviewing any errors.

1. Why avoid holding a thermometer by its bulb?

   The unit automatically changes to grams / The scale labels move to another location / The hand can affect the sensitive part’s temperature

2. A reading is changing because the sample itself is cooling. What should the record include?

   No units / The measurement time and changing conditions / Only a preferred earlier value

3. Which plan best investigates a disputed reading?

   Pick whichever number is most convenient / Repeat with the same stable sample and check placement, eye level and scale / Change the sample and instrument without keeping records

4. A supplied melting ice-water record stays constant under steady conditions. What can be concluded?

   A plateau can occur during melting; the record alone does not prove the instrument is stuck / Every constant reading proves a broken thermometer / The mixture cannot contain matter

5. D2 has 32/21 °C and D3 has 31/19 °C. Which has a wider daily range?

   D3, because 12 °C is greater than 11 °C / D2, because its maximum alone is higher / They must be equal

6. What should a real weather table include besides temperature values?

   Only decorative colours / Only the learner’s initials / Dates, place, units and source

Final check · Set 2

Try one set after the lessons. Use the other set after reviewing any errors.

1. Which position matches the supplied model?

   Upright with the bulb submerged and not touching the beaker / Tilted with the bulb against the wall / Upright but with the bulb only in air

2. An actual probe’s instructions require a different immersion depth. Which should be followed?

   The drawing regardless of the instrument / Whatever gives the highest reading / The actual instrument’s instructions and approved setup

3. A scale marked every 1 °C is reported as exactly 28.037 °C with no estimation method. What needs checking?

   Whether the number has enough decorative zeros / Whether temperature uses grams / Whether those extra digits are supported

4. Readings of cooling water are taken at different times. What is a plausible reason for a difference?

   Temperature cannot change / The sample temperature may have changed with time / Every observer must have made the same mistake

5. Can these five invented days prove that next week must be hotter?

   Yes; invented data predicts real weather / No; they do not establish a certain forecast / Yes; the last maximum guarantees the future

6. For D5, 33 °C maximum and 22 °C minimum give…

   An 11 °C daily range / A 55 °C daily range / A 22 °C daily range