Where It Gives Way
A 55-minute Grade 4 lesson on running controlled tests to failure and using the failure point to improve a prototype.
Where It Gives Way is a free 55-minute Grade 3 to Grade 5 science lesson plan for Common Core standard 3-5-ETS1-3 — run fair tests, controlling the variables, to find what to improve. 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:
- Grade 3 to Grade 5
- Length:
- 55 minutes
- Standard:
- 3-5-ETS1-3
Grade 3 to Grade 5 · Engineering Design
3-5-ETS1-3
Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved.
Objective
Students will be able to test a prototype to failure under controlled conditions and improve its weakest point.
Students are successful when they can
- Names the controlled variables.
- Records where and at what load it failed.
- Improves that point and retests.
What you need
- Prototypes from the previous lesson, weights, a loading hook
- A record sheet with a controls line and a failure-point line
- The printable practice sheet linked at the end of this plan
The lesson
Warm-up
5 min- Load a prototype until it fails and ask what the class learned.
- Push for where it failed, not just that it did.
Teach — control, load in steps, watch the joint
14 min- List the controls: same span, same support, same loading point, same step size.
- Load in equal steps and record the load at each step.
- At failure, record BOTH the load and the place.
- Say the term: that place is the failure point.
- Strengthen only that point and retest with the same controls.
- Compare the two failure loads and say whether the change worked.
“Where did it give way? That is the only thing you change.”
Investigate — test, improve, retest
19 min- Groups load their prototype in equal steps to failure, three times.
- They record the load and the failure point each time.
- They make one change to that point.
- They retest under the same controls and compare the loads.
Independent practice
14 min- Students complete the 'Where It Gives Way' page.
- Check answers name controlled variables.
Close
3 min- Ask whose failure point moved after the improvement.
What goes wrong, and why
Each of these is a reasoning error rather than carelessness. The fix addresses the reasoning.
Records only the failure load.
Why: The number feels like the result.
Fix: Where it failed is what tells you what to change.
Changes two things after a failure.
Why: Both looked weak.
Fix: One change per cycle, or you cannot attribute the improvement.
Tests once and concludes.
Why: It failed clearly.
Fix: Repeat. A single failure may be a bad join rather than a bad design.
If they are not there yet
- A prototype supplied and a controls checklist to tick.
- Two loading steps rather than many.
If they finish early
- Predict the new failure load before retesting.
- Find a design whose failure point cannot be improved.
- Say what test would be unfair however careful you were.
Exit ticket
Your bridge fails at the same joint three times. Name the controls you kept, and what you would change.
What to look for: Controls such as span, support and loading, with only that joint strengthened. A change with no controls named means the fair-test idea needs another run.
Printable practice for 3-5-ETS1-3
Free to print and copy, answer key included. Each sheet can generate a fresh set of problems for a retake.
- Where It Gives WayCircle the best answer.
Questions about Where It Gives Way
How long does the Where It Gives Way lesson take?
55 minutes, split across 5 timed sections: warm-up 5 min, teach 14 min, investigate 19 min, independent practice 14 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 Where It Gives Way teach?
3-5-ETS1-3 — 3-5-ETS1-3, Engineering Design for Grade 3 to Grade 5: “Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved.” In plain terms, run fair tests, controlling the variables, to find what to improve.
What do I need to teach this lesson?
Prototypes from the previous lesson, weights, a loading hook, a record sheet with a controls line and a failure-point line 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: records only the failure load; changes two things after a failure and tests once and concludes. 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: “Your bridge fails at the same joint three times. Name the controls you kept, and what you would change.” Controls such as span, support and loading, with only that joint strengthened. A change with no controls named means the fair-test idea 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 Where It Gives Way?
Yes — 1 printable 3-5-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 Where It Gives Way 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 3-5-ETS1-3 of the Next Generation Science Standards.