Save the discussions of why the Arctic Circle has a midnight sun and such for the dialectic stage. It is enough that grammar stage children know that it does. A map skills workbook can be used later in the grammar stage to practice and solidify any map work concepts that might be lacking. Memorizing Geographical Facts Even though a child's understanding of how space, distance, and places are represented two-dimensionally will take time to fully mature, there is plenty of geographic information that children can master in the grammar stage. Children can learn by rote the capitals of states and countries of the world before they even have a clear idea of what exactly a capital is.
Children can learn to identify the names of countries that are pointed out on a map.
Keep in mind that a child has roughly six years to acquire this information. This could be easily included with the regular world history study taking place in the grammar stage, without requiring separate study time.