Preview · the opening missionRead this to the class:
A Grade 4 student wore a patch over one eye for a week while an infection healed. At recess he kept missing the ball. At lunch he poured juice onto the table, beside the cup. By the next week his eyes were fine, but he kept wondering. Your team's job: find out what two eyes do that one eye can't.
Teams of three, with three jobs that rotate: Holder (holds the pen still), Tester (tries the cap challenge), Recorder (counts hits and misses).
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
- Cap challenge results
- Blind spot
- What we kept the same, and what we changed
- Claim, evidence, reasoning
- A note to the boy with the eye patch
- 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
- Carries out a fair test
- Explains depth
- Explains the blind spot
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 you have two eyes?” take?
45–60 min. Group size: teams of 3.
How much prep does it need?
10 minutes: make one blind-spot card to show the class (a bold + on the left and a filled dot 1 cm wide on the right, 8 cm apart). Collect one pen with a cap per team.
What materials do I need?
Pen or marker with a cap; blank index card, 13 × 8 cm (5 × 3 in) or larger; black marker; ruler, 30 cm (12 in), or a metre stick. Cost: free with classroom pens and index cards; about $5 for extra cards.
Which curriculum standards does it cover?
NGSS (US): 4-LS1-2 and 4-PS4-2 (partly). It also matches BC Science 4, Big Ideas.
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”; “Cap challenge results”; “Blind spot”; “What we kept the same, and what we changed”; “Claim, evidence, reasoning”; “A note to the boy with the eye patch” 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.