Campfires burn trees, and a new publication from NASA explains how kids can save trees by using the sun to cook s’mores.

A lengthy set of instructions on the NASA “Climate Kids” website details how children can use a cardboard box, aluminum foil, sticks, glue and tape to create their own “solar oven” to cook their S’mores.

It’s a fun experiment I guess, but children who are anxious to get eating might be discouraged that it takes up to an hour and a half before the S’more is ready to eat.

The instructions point out that after propping up your solar flaps, you have to wait at least 30 minutes for the “oven” to “preheat.”

Once the marshmallows are in the oven, the instructions note that it might take up to a full hour for them to melt, plus an additional period of time to melt the chocolate.