Magnifying sheet from dollar store 3x magnification listed Stainless steel bowl from dollar store Paperclip sand filled bowl to magnifying sheet. —-x see note at end Sunlight. The sand can heat to over 250 C+ in the sun with magnification. This is free energy that can be used for heating and cooking. Handle metal with oven mittens, beware of flammable items in area. Theoretically with enought sun and time, it should work marvellously!
Tell me why the heated sand won't melt and burn the plastic lens?
it will eventually, needs space between it and the magnifier