Space criss-cross puzzle

Space vocabulary interlocks better than almost anything else on this site. TELESCOPE, ASTRONAUT and CONSTELLATION are long, vowel-rich and full of the common letters a grid needs for its crossings, so the puzzles come out with the sprawling shape a criss-cross is supposed to have rather than a tight square in the middle of the page.

They are also words children meet far more often than they write. A ten-year-old has heard GRAVITY hundreds of times and may never have spelled it out. Putting it into seven squares, with the R fixed because ROCKET already crosses there, is frequently the first time the spelling has had to be exactly right rather than roughly right.

That makes this a good revision sheet at the end of a topic rather than an introduction to one. The words should be familiar before the puzzle, because a criss-cross gives no clues and no context: the word bank is the whole of the help available. Handed out cold to a class that has not done the topic, it becomes a copying exercise.

The four grids go from ten words to twenty, and the larger two use planet names, which have a useful property: a child who knows the order of the planets can work through them mentally and check each length against the gaps, which is a completely different solving strategy from letter-matching.