Measure 5 tablespoons of water into a heat-proof liquid measuring cup. Heat in a microwave until the water is very hot to the touch.
Add 1 gram of benzoic acid to the hot water. Stir to dissolve the benzoic acid. Set this solution aside to cool. The slower it cools, the more the resulting benzoic acid flakes will resemble snowflakes.
Clean and dry a jar that holds approximately 4 oz. Make sure the toy you've chosen fits in the jar. If not, you'll need to find another toy or plastic figurine to use as the central decoration in your snow globe.
Place a bead of hot glue on the inside of the jar's lid, right in the center, and then position the plastic toy on it. Use tweezers if you need to to get the toy in the right position. Allow the glue to dry completely.
Check the benzoic acid solution. If it's at room temperature, it's ready to pour into the jar. Add enough room-temperature water as you need to make the jar as full as possible.
Screw the lid onto the jar. To make a permanent snow globe, run a bead of glue around the edge of the lid. For a less permanent snow globe, tape the lid to the jar with electrical tape.