Was It a Fair Comparison? student packet

Read before evaluating a comparison

Target: Decide whether a comparison isolates sleeve performance. Prerequisites: read units/time, distinguish starts and changes, subtract whole numbers. If needed use Read Temperature Data Before Explaining It or the support below: 10→14°C is 4°C warming; 30→26°C is 4°C cooling.

First name the question. To compare complete sleeve designs, keep other relevant conditions matched. To investigate a single sleeve feature, vary that feature while keeping the rest of the sleeve design matched too. A confound is another relevant difference that prevents assigning the result to the intended factor alone.

Imagined setup cards for a paper comparison of complete sleeve designs. No results supplied.

1.What is being compared? What would be measured? Name two conditions kept the same.

2.Would changing both the sleeve and water mass still isolate sleeve performance? Explain.

Two things changed

Room 22°C, same 15-minute exposure, matching cups/lids and thermometer procedure. Two complete sleeve designs; water masses and starts differ.

1.Find both temperature changes. Can the difference be assigned to the sleeve alone? Explain.

2.Name the confounds. Propose actual matching conditions for a better sleeve comparison.

3.What descriptive conclusion is still possible? Does comparing changes repair the confounds?

Guided practice · Repair setup cards

Paper plans, not collected readings. The question asks which complete sleeve better limits warming.

1.Identify what differs besides sleeve design. Explain why that matters.

2.Rewrite D’s setup to match C’s relevant conditions while still comparing sleeves C and D.

3.Give a consistent measurement and recording plan, including repeated trials. If the question were about one sleeve material, what else would need matching?

Independent task · Fresh critique

Both setups are in a 24°C room. Cups, lids, exposure position and reading method match. The sleeve design, mass and duration differ.

1.Calculate each change. A fictional answer says “F works better because its water warmed less.” What is supported and what is too strong?

2.Identify the confounds and specify a repaired comparison with actual masses, starts and duration.

3.Describe how to repeat and record that comparison. State one limit even after repair.

Subtraction does not fix a confound

Same 20 minutes in a 22°C room; cups, lids and method match. Sleeve and mass differ.

1.Find both changes. Can the lower increase isolate a sleeve effect? Repair the comparison.

Fresh check

New equal samples in a 23°C room, same cups/lids, method and 15-minute exposure. This is one matched trial.

2.What bounded sleeve comparison is supported? What is not established?

Specify a usable plan

Three separate trials of fresh 100 g samples starting at 10°C in a 22°C room. Cups/lids, position, 20-minute interval and reading procedure match within and across trials.

1.Which sleeve shows less warming across these trials? Does this prove a particular material property?

2.Write a paper retest plan: compared factor, matched conditions, measurement method, number of fresh trials, and fields to record. Do not invent new readings.

Fresh check

Fresh equal 100 g water, 23°C room, matching cups/lids and reading method. Times differ.

3.What needs repairing before attributing the result to the sleeve alone?

Later check · Cooling and a repaired test

Paper cooling task. Both in a 22°C room for 15 minutes; cups, lids and method match. Masses differ.

1.Find both falls. Explain why “Q better limits cooling because its final value is higher” does not isolate a sleeve effect.

Data Tr · Repaired paper record: fresh 100 g samples all begin at 36°C in a 22°C room. Cups/lids, position, method and 15-minute interval match within and across trials.

2.What comparison is now supported across trials? Include one meaningful limit.

3.Does this paper record show that you constructed and tested a device? Explain.