: cardboard, matboard (for insulation—black on one side and white on the other aide), masking tape, clear plastic wrap, thermometer, one small can painted black and filled with water (storage mass).
A. Cut out 3 rectangular sizes from cardboard: 8”x12”, 10”x12”. 4”x12”.
B. Cut out 2 identical right triangles, size 8’x 10 .
C. Assemble as shown in Figure 8. Use rubber cement on all parts except 10 x12 rectangle. Attach the 10 x12 rectangle with tape across bottom so it can open and close.
D. Use tape to attach plastic wrap.
E. Cut out 8”x12” matboard for insulation (black on one aide and white on the other aide).