## Wednesday, February 17, 2016

### Polishing a ... (trying to fix a textbook lesson)

Graham Fletcher called out a bad textbook in his recent post, Placing a hit on Pseudo-Context.

He was inspired to create a related lesson. Here is another, super low effort attempt to salvage something from the original textbook. What do you think?

1. What is our scenario?

Okay, obviously, this sets us up to make boxes to hold DVDs. What do the kids think? Why is Mike doing this? What should he consider?

Seems natural that the teacher should have on-hand a bunch of DVDs and construction material.

2. So, Mike made some progress constructing his box:

Some questions for the kids to debate:
• What shape did Mike choose?
• What dimensions?
3. Here are the choices Mike made:

• What do you notice?
• How do his choices compare with the ones you made?
• What do you wonder ?
*UPDATE* I talked through this post with J1, my 8 year old. Here are some of the things he explored and talked about:

• How would the DVDs inside the box be arranged? Stacked on top of each other, multiple stacks, with some type of dividers between them or not?
• How big are DVDs? He measured the diameter of one, then stacked 10 (in protective covers) to measure thickness.
• How many DVDs does Mike have? How does the desired structure of the box change if there are 5, 20, 100, 1000 DVDs? This also linked to practical considerations around finding and extracting a particular DVD from the box and what would be suitable materials for the box (paper, cardboard, wood).
• Since he measured our discs in cm and the book had inches, we had a conversation about conversions.
• As I'd guessed, getting him to think about the dimensions of his own box before seeing the textbook dimensions made him wonder about symmetry.
• Note: this prompt really didn't get him to think much about the volume of the box. I think this is because there isn't really a natural trade-off between the dimensions for DVDs, so it is natural to think of the base area compared with a single DVD and the height based on the number of DVDs. Graham's sugar cubes was much more direct for engaging the concept V = L x W x H.

#### 1 comment:

1. I really like how you've drawn this out Joshua. The focus here shifts from quantities to context, and that's where we want student thinking to be. I appreciate how you taken a bad problem and made it better with simple fixes that teachers can do on a regular basis. Sweet!