The Word Family That Split the Class
Mr. Delgado's Grade 3 class is building "word families" on the board. A family is a set of pairs that all show the same relationship. Three pairs are already in place: glove–hand, boot–foot, hat–head. Ana adds scarf–neck without hesitating. Then Mr. Delgado holds up a fourth card with a blank: belt–?. The choices are waist, buckle, leather, and trousers.
Ben votes for waist: "A belt goes around a waist, just like a hat goes on a head." Ana votes for buckle: "A buckle is part of a belt, and a scarf has a fringe." The class splits, and both students can defend an answer. Mr. Delgado does not say who is right. Instead he asks for a test the whole class can run on every card, so the family is judged as a set rather than one pair at a time. He also writes pilot–airplane on the board and asks whether it belongs in the same family as glove–hand.
1. Which choice completes belt–? so that it matches the family? Show the sentence you read each pair as, and use that sentence to rule out the other three choices.
Read the worked answer
Answer: waist.
Read every pair as one sentence: a ___ goes on a ___.
- A glove goes on a hand. ✔
- A boot goes on a foot. ✔
- A hat goes on a head. ✔
- A scarf goes on a neck. ✔
- A belt goes on a waist. ✔
Now test the others in the same sentence:
- "A belt goes on a buckle" - no. A buckle goes on a belt. That reverses the pair, so the relationship is part-to-whole, not worn-on.
- "A belt goes on leather" - no. Leather is what a belt is made of, a material clue.
- "A belt goes on trousers" - weak. A belt is worn with trousers, but trousers are not a body part, and every second word in the family (hand, foot, head, neck) is a body part.
Waist wins on two separate tests: the sentence still makes sense, and the second word keeps the same kind of meaning as the rest of the family.
2. Ana says pilot–airplane is the same family as glove–hand, because "a pilot is to an airplane as a glove is to a hand - both are things people use." Evaluate her reasoning.
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Ana's sentence test breaks in two places.
The sentence does not survive substitution. "A pilot goes on an airplane" is false. The glove–hand sentence is goes on. The pilot–airplane sentence is operates or flies.
The pair is built from different kinds of words. Glove–hand links a thing worn to a body part. Pilot–airplane links a person to a vehicle. Ana's phrase "things people use" is loose enough to cover almost anything, which is a warning sign: a good relationship is narrow enough to predict the next pair.
Pilot–airplane belongs with driver–car and captain–ship. If the class added it to glove–hand, the family would have no single rule, and the belt question could no longer be answered by the sentence test.
3. A new card arrives: finger–hand. One student says it fits the belt–buckle family because "a finger is on a hand." Decide, and state a tie-breaking rule for cards that seem to fit two families at once.
Read the worked answer
finger–hand is a part-and-whole pair, like buckle–belt. A finger is one piece of a hand; a buckle is one piece of a belt. Those two belong together in their own family.
It is not a worn-on pair, because nobody wears a finger on a hand the way a glove is worn on a hand. Direction matters here: finger → hand goes part → whole, while glove → hand goes worn item → body part.
Tie-breaking rule for the class:
- Write the full sentence for the card, then check whether the sentence already used for the family still holds without changing any words.
- Prefer the family that keeps all pairs in one direction and one relation type.
- If a card could fit two families, it belongs to the one where the relation is narrower and more specific. Moving one card is cheaper than rewriting the whole family.