PHYSICS PROBLEM SOLVING

Why do Some Groups Use Alternate Claims?
Turning to the five groups that do use Alternate Claims, I looked at the
elaboration that leads up to the Alternate Claim and noticed a pattern (Figure 4-3). In
two out of seven of the prototypes (4B2, 4C) a Modified Claim precedes the Alternate
Claim. In five prototypes (2A, 2B, 4B1, 5B1, 5B2), there is little or no elaboration before
the Alternate Claim, and no Modified Claim precedes the Alternate Claim.

2A,2B,4Use More ACB1,4B2,4C,5B1,5^ B2

(5 Groups)

7

No MC C --> Abefore C AC

2A,2B,4B1,5B1,5B2

C --> MC --> AC^5

MC be4Bfore 2,4CAC

2

UsUse Few AC e MC

2D,3A,3B,4A7A,4D,5A,5C,6B

(9 Groups)

9

Prototype Patterns^16

Figure 4-3. Elaboration of an Alternate Claim.
Consider first an example from Group 4C (Table 4-1, page 138) where student
SV’s Modified Claim (line 58) elicits a Challenge and Alternate Claim from EW. (Direct
challenges are rare and the “No” in Line 59 could be interpreted as being a part of the
Alternate Claim and not actually a separate challenge.) Although SV’s Modified Claim
is correct, EW is responding to here on the basis of what he said in 57. In the next
example (Table 4-2, page 138) from Group 4B, one Alternate Claim immediately follows
another (lines 24 and 25).