Abstract: A container for holding a liquid having transparent walls and an opening near its upper end, utilizes a heat absorbing insert element within the container comprised of a sheet of flexible black material that can be situated therein so as to expose a relatively large surface area to the sun's rays which pass through the container's transparent walls, thereby increasing the rate of solar heat absorption and rate of heating water within the container.

Abstract: An inflatable solar oven is comprised of two sheets of flexible material which are sealed at their edges to form an enclosure. The top sheet is clear and the bottom sheet has a reflective layer. The two sheets can be inflated to form a spherical enclosure by passing air through an edge opening that is also large enough to access a water or food holding receptacle which can be placed with the inflated enclosure. Extended portions of the sheets that form the opening can be rolled up to form a closure for it. The inflated enclosure can be secured to the ground in an appropriate position to receive the sun's rays which pass through the clear sheet and reflect from the bottom sheet to heat the receptacle therein.