Which One Actually Worked?
A 50-minute Grade 1 lesson on analysing test data from two signal designs to compare how each performs.
Which One Actually Worked? is a free 50-minute Kindergarten to Grade 2 science lesson plan for Common Core standard K-2-ETS1-3 — test two designs for the same problem and compare how each performs. It is timed across 5 sections, gives the exact wording to use where the wording carries the mathematics, names 3 misconceptions with the teaching move that addresses each, and ends with an exit ticket and a printable worksheet with its answer key.
- Grade:
- Kindergarten to Grade 2
- Length:
- 50 minutes
- Standard:
- K-2-ETS1-3
Kindergarten to Grade 2 · Engineering Design
K-2-ETS1-3
Analyze data from tests of two objects designed to solve the same problem to compare the strengths and weaknesses of how each performs.
Objective
Students will be able to use tallies from a fair test to compare two designs.
Students are successful when they can
- Tests both designs the same way.
- Reads which did better from the tallies.
- Names a strength of the one that did worse.
What you need
- Two signal devices from the earlier lesson, a measured distance
- A tally chart with two columns
- The printable practice sheet linked at the end of this plan
The lesson
Warm-up — one go each is not enough
5 min- Send each signal once. One works, one does not.
- Ask whether that settles which is better.
Teach — ten goes and a tally
13 min- Send signal A ten times at the marked distance and tally the hits.
- Do the same for signal B, same distance, same partner.
- Draw both tallies as bars and compare.
- Ask which did the job better, using the bars.
- Now ask for a strength of the losing one: quicker, quieter, easier to carry.
- Say the rule: compare on the results, and say what each one is good at.
“How many out of ten? Now say it for the other one.”
Investigate — test two signals
17 min- Pairs test two signals ten times each at the same distance.
- They tally hits for both and draw the bars.
- They write one strength and one weakness for each.
- They say which they would use, and for which situation.
Independent practice
12 min- Students complete the 'Which One Actually Worked?' page.
- Check the answer quotes a number from the results.
Close
3 min- Ask which signal the class would take on a school trip, and why.
What goes wrong, and why
Each of these is a reasoning error rather than carelessness. The fix addresses the reasoning.
Decides after one try each.
Why: One try gave an answer.
Fix: Try again. If the two tries disagree, one was not enough.
Tests the two designs at different distances.
Why: Each was tested where it worked.
Fix: Same distance, same partner. Otherwise the tallies cannot be compared.
Says the losing design has no strengths.
Why: It lost.
Fix: Ask about carrying it, or using it quietly. Losing at one job is not losing at all of them.
If they are not there yet
- Five goes rather than ten.
- A tally chart with the first column filled.
If they finish early
- Find a distance where the loser wins.
- Combine the best of both into a third design.
- Say what other test would settle it.
Exit ticket
Signal A worked 9 times out of 10 and signal B worked 4. Which is better, and what might B still be good for?
What to look for: A, on the tallies, with B credited for something like being quiet or quick. A verdict with no number means the results step needs another run.
Printable practice for K-2-ETS1-3
Free to print and copy, answer key included. Each sheet can generate a fresh set of problems for a retake.
- Which One Actually Worked?Look at the results, then answer.
Questions about Which One Actually Worked?
How long does the Which One Actually Worked? lesson take?
50 minutes, split across 5 timed sections: warm-up 5 min, teach 13 min, investigate 17 min, independent practice 12 min, close 3 min. The minutes are stated per section and add up to the stated length, so the plan can be cut or extended at a section boundary rather than abandoned halfway.
Which standard does Which One Actually Worked? teach?
K-2-ETS1-3 — K-2-ETS1-3, Engineering Design for Kindergarten to Grade 2: “Analyze data from tests of two objects designed to solve the same problem to compare the strengths and weaknesses of how each performs.” In plain terms, test two designs for the same problem and compare how each performs.
What do I need to teach this lesson?
Two signal devices from the earlier lesson, a measured distance, a tally chart with two columns and the printable practice sheet linked at the end of this plan. Everything listed is either ordinary classroom equipment or a free printable from this site — there is nothing to buy and nothing to prepare beyond photocopying.
What mistakes should I expect in this lesson?
Three, each a reasoning error rather than carelessness: decides after one try each; tests the two designs at different distances and says the losing design has no strengths. The plan gives the thinking behind each one and the teaching move that addresses the thinking rather than the symptom.
How do I know whether the lesson worked?
The exit ticket asks: “Signal A worked 9 times out of 10 and signal B worked 4. Which is better, and what might B still be good for?.” A, on the tallies, with B credited for something like being quiet or quick. A verdict with no number means the results step needs another run. That tells you whether the class needs a reteach or a thirty-second conversation before you plan tomorrow.
Is there a worksheet to go with Which One Actually Worked??
Yes — 1 printable K-2-ETS1-3 worksheet, linked at the end of the plan and free like the rest of the site. Each one comes with an answer key and 25 versions, so the practice after the lesson can be a different paper on every desk.
Is Which One Actually Worked? free to use?
Yes. The plan, its printables and their answer keys are free to read, print and photocopy for your own class, with no account and no email capture. It was last reviewed on 8 September 2026. Please do not resell it or republish it as your own.
Last reviewed 2026-09-08. Aligned to K-2-ETS1-3 of the Next Generation Science Standards.