One partner sorts the blocks into two or more sets and challenges the other partner to determine the sorting rule. Partners work together to place a sticky dot on each flat face of a geoblock, then transfers the dots from the geoblock to a piece of paper to be kept with that geoblock. Challenge students to organize the data by ordering the geoblocks according to the number of flat faces each one has. Partners test their estimate by pouring a cup of water into the jar and marking the resulting level of water on the jar. Partners continue to pour water into the jar and mark each new water level, changing their estimates as desires.
Students compare capacities of other containers.
Partners discuss the outcome of their test and make conjectures about what they could do to improve the strength of their building. If time allows, partners test their new conjectures. The other partner will select all the geoblocks from the set that fit that attribute. The first partner names another attribute of the geoblock so that second partner can identify which of the smaller set of blocks chosen in the first round also fit the new clue. This continues until only one block is left, the secret block.