Compare by lookingTaller or shorter
Each pair stands on the same floor. Look at the tops.
Standing two children back to back is the first height comparison anyone makes. These free printable worksheets stand two objects on one floor and ask a child to circle the taller or the shorter, with an answer sheet.
If they get stuck

The answer key prints on a separate page.
The shared floor does the same job here as a start line does for length. Because both things stand on it, only the tops need comparing. Towers, trees, flowers and candles look quite different from each other, and that is useful, because a child has to compare the height and not be distracted by how wide or how bushy a thing is.
Tall and short are also easy words to mix up with big and small. A squat tree can be bigger in every other way and still be shorter than a thin candle. If a child picks the wider one, point at the two tops and ask which is closer to the ceiling.
Circle the taller one.