After building towers made of blocks or Lego© building blocks, children will contrast heights to determine which buildings are taller.
Explain to your child that he will build two towers out of blocks and then determine which is taller and which is shorter. Allow time to build, and then set the two structures side-by-side. Next, say, “Now we can contrast our two buildings. To contrast means to look at the two towers to see how they are different.” By holding an arm or ruler over the two towers, the difference in height of the towers can be observed. You can say, “See how this tower touches my arm, and this other one does not?”
Together, you can also count the number of wooden blocks or Legos© that were used. For example, “We counted 7 blocks in my tower and 11 blocks in your tower. 11 blocks is taller than 7 blocks.”
Next, you can add and remove blocks from each tower and contrast them again. Talk about how you arrived at the new results, for example: “You added three more blocks to this tower and now it’s taller than the other one!” or “You removed one Lego© from this tower and now both towers are the same height.”