Bone marrow. The inside of your bones are filled with a soft tissue called marrow. There are two types of bone marrow: red and yellow. Red bone marrow is where all new red blood cells, white blood cells, and platelets are made.
Mine is 8m x 7m (3m is 10 feet, so around 27 x 23 feet). This is normal for an Australian classroom, although there's a fair bit of variation.
The Museum has a limited number of lockers available. The dimensions are: Small- Height 16, Width of door 8.5, Width of interior 12, Depth 16. Medium- Height 22, Width of door 8.5, Width of interior 12, Depth 16. Large- Height 34, Width of door 8.5, Width of interior 12, Depth 16.