Met, not met, or a limit broken

What this lesson teaches: A design solves the problem only when every criterion is met and no constraint is broken.

Video rendering. This video is in the Peps pipeline (about 75 seconds, 150 spoken words). Until it lands, the storyboard below is the video, beat by beat.

The script (narration and what is on screen) — open

#	Narration	On screen
1	Mr. Park's class built pencil holders, and here is his list. Two criteria say the holder must keep ten pencils standing and must not tip when bumped. One constraint says use only one sheet of cardboard.	Mr. Park's classroom; a list card with three lines: KEEP 10 PENCILS STANDING / DO NOT TIP WHEN BUMPED / ONLY 1 SHEET OF CARDBOARD; no title slide
2	Luis's holder keeps ten pencils standing, so that criterion is met.	Luis's wide holder with ten pencils standing; a green tick beside the first line; chip MET
3	Luis bumps the desk hard and the holder stays up, so that criterion is met.	the desk wobbles with three long motion lines; the holder stays; a green tick beside the second line; chip MET
4	But Luis used two sheets, so that constraint is broken.	two sheets of cardboard beside the holder; a red cross beside the third line; chip BROKEN
5	Erin's holder keeps ten pencils standing, so that criterion is met. Erin bumps the desk hard and the holder tips over, so that criterion is not met. She used one sheet, so that constraint is kept.	Erin's tall holder: ten pencils, green tick, chip MET; the desk wobbles, the holder tips, red cross, chip NOT MET; one sheet of cardboard, green tick, chip KEPT
6	So, here's what we've seen. A design solves the problem when every criterion is met and no constraint is broken. If one criterion is not met or one constraint is broken, the design does not solve the problem.	rule slide reuses the list with both holders' ticks and crosses; rule text
7	Okay, now your turn.	the attached question appears

Mr. Park's class built pencil holders, and here is his list. Two criteria say the holder must keep ten pencils standing up and must not tip when the desk is bumped. One constraint says use only one sheet of cardboard.

Luis's holder

Ten pencils stand up. That criterion is met.

Luis bumps the desk hard. The holder stays up. That criterion is met.

But Luis used two sheets of cardboard. The limit was one sheet, so that constraint is broken.

Erin's holder

Ten pencils stand up. That criterion is met.

Erin bumps the desk hard. The holder tips over. That criterion is not met.

Erin used one sheet of cardboard. That constraint is kept.

Mr. Park's list	Luis's holder	Erin's holder
Keep ten pencils standing up (criterion)	met	met
Do not tip when the desk is bumped (criterion)	met	not met
Use only one sheet of cardboard (constraint)	broken	kept

Luis's holder met both criteria but broke the constraint. Erin's holder kept the constraint but did not meet one criterion. Neither holder solves the problem yet.

A design solves the problem when every criterion is met and no constraint is broken.

If one criterion is not met or one constraint is broken, the design does not solve the problem.

Okay, now your turn

One easy question straight after the video: the student answers it to move on.

After the video

A paper cup must hold water for one minute, using one sheet of paper. One cup holds the water but was made from two sheets. Which sentence is true of this cup?

Quiz

(a) fluency: one result at a time, placed as met / not met / broken / kept; then two yes / no items on the rule. Fresh contexts, never the lesson's own pencil holder.

Question 1

A paper bridge must hold ten coins, using only one sheet of paper. Bridge A holds ten coins. Which is true of the "hold ten coins" criterion?

Question 2

A paper bridge must hold ten coins, using only one sheet of paper. Bridge B holds four coins, then bends. Which is true of the "hold ten coins" criterion?

Question 3

A phone stand must hold a phone up while a video plays, using only one sheet of cardboard. One stand holds the phone up but was made from three sheets. Which is true of the "one sheet of cardboard" constraint?

Question 4

A seed planter must hold the soil in when it is carried, and be finished by Friday. The planter spills soil when carried. Which is true of the "hold the soil in" criterion?

Question 5

A seed planter must be finished by Friday. The planter is finished on Wednesday. Which is true of the "finished by Friday" constraint?

Question 6

A seed planter must hold the soil in when it is carried, and be finished by Friday. One planter holds the soil in and is finished on Thursday. Does it solve the problem?

Question 7

A seed planter must hold the soil in when it is carried, and be finished by Friday. One planter holds the soil in and is finished the next Monday. Does it solve the problem?

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