Preview · the opening missionRead this to the class:
Every year at festival time, a family strings lights along the porch. One evening, the whole string goes dark. Every bulb looks fine. Their neighbour's string has one dark bulb, and the rest keep shining. "Why does ours do all or nothing?" Your team's job: find two ways to wire two bulbs, and figure out which one acts like the porch lights.
Jobs rotate after each setup: Builder (clips the leads), Checker (watches brightness and feels for warmth), Recorder (draws and records).
Look inside the PDF
Sample pages, stamped “preview”. The download is the clean, full lesson.
In the full lesson PDF
- Predict (5–10 min)
- Hunt (20 min)
- Reveal (10–15 min)
- Act (10 min)
- Background for the teacher
- Assessment
- Student sheet
On the student sheet
- My prediction
- Our results
- Draw Setup A and Setup B
- What we kept the same, and what we changed
- Claim, evidence, reasoning
- A note to the family
- Exit ticket
US Letter, prints cleanly in black and white. The student sheet is on its own page, ready to photocopy.
Free with an account (any 3 lessons), or US$19 / C$25 for all 4 lessons in this unit.
What students show by the end
- Builds both circuits
- Compares results
- Explains with paths
From the lesson’s rubric, which scores each one as not yet, getting there or got it.
Questions teachers ask
How long does “Why do some string lights all go out at once?” take?
45–60 min. Group size: teams of 3.
How much prep does it need?
10 minutes: put fresh batteries in each holder and test every bulb. Bulbs on a team must match (same rating) or the brightness comparison won't be fair.
What materials do I need?
Battery holder for 2 AA batteries, with 2 AA alkaline batteries (3 V total); bulb holder with a matching 2.5 V flashlight bulb; alligator-clip leads (about $8 for a pack of 10 online); a string of holiday mini lights, unplugged, to pass around (optional). Cost: about $5 for a class of 30, if you have battery holders and bulbs.
Which curriculum standards does it cover?
NGSS (US): 4-PS3-2. It also matches Ontario Science and Technology, Grade 6 and Cambridge Primary Science, Stages 4 and 6 (not endorsed by Cambridge).
What’s in the lesson PDF?
A teacher guide that walks you through predict, hunt, reveal, act, background for the teacher and assessment, then a student sheet (“My prediction”; “Our results”; “Draw Setup A and Setup B”; “What we kept the same, and what we changed”; “Claim, evidence, reasoning”; “A note to the family” and “Exit ticket”) on its own page, ready to photocopy. It’s US Letter and prints cleanly in black and white.
Can I try it for free?
Yes. A free account includes any 3 full lessons of your choice, and this can be one of them. After that, this unit is US$19 (C$25) for all 4 lessons, yours to keep, or every lesson is US$79 (C$109) a year.