Saw dust is nothing but wooden material and wood is a bad conductor.

Hence heat transfer between ice and atmosphere is reduced and ice will remain as ice without becoming water for a longer period

Iron is a good conductor of heat and expansion takes place when temperature is increased and contracts when temperature is reduced.

There must be provision to take care of this expansion and contraction and the same is obtained by having rollers.

Box type solar cooker consists of a shallow box coated black. A flat glass cover covers the shallow box.Items which are to be heated are kept in different boxes which are covered with black colour coating.

In addition there will be a foldable cover with a mirror and this cover can be placed at different inclinations so that maximum amount of sun rays can be reflected on to the glass cover and further to the shallow box.The heat of the sun rays are trapped inside this box and the heat is transferred to the items that are kept inside.

Thus we can utilize the sun energy.

Area of the square is 2304sq.m The side of the square becomes 48m. The sides of the rectangle will be 48m & 48*4=192m The area of rectangle will be 48*192 sq.m The difference of the areas will be 48*192 - 48*48=6912sq.m

15 days

16 poles