A collage is a design created out of found objects, from cut paper to cloth, leaves, string and all sorts of things. To make a sandwich bag collage, start with a plastic sandwich bag. Lay it flat on the table and arrange small, flat, lightweight collage objects inside. Use colored paper snipped and torn into interesting shapes, giftwrap paper and magazine photos, sequins and glitter and tinsel, bits of lace and cloth. Plan your design so it will look good from both sides.
When all your collage items are in place, slip the plastic bag between two pieces of aluminum foil. Have an adult press a warm iron on the foil for 10 or 20 seconds. The plastic will melt together and hold all your collage items in place. If a whole classroom is doing this project and your adult is ironing a lot of collage bags, it is good for them to work on a porch outside or in a room with really good ventilation to minimize any hot plastic smell in the air.
A sandwich bag collage looks great hanging in a window. It looks like a mini stained glass suncatcher!