Take an enclosed box that is at least two feet tall. Secure the flaps of the box to ensure it is closed securely.
Cut one side of the box out. Replace the side that was cut out with plastic wrap. This will ensure that the student can see the smoke-formed tornado. Ensure that the wrap is secure and the seams are closed tightly.
Place black construction paper inside of the box. This will make it more visible for students to see the smoke-formed tornado.
Take a small personal fan and cut out a circle in the top of the box. Ensure that the fan circulates backwards to circulate the wind in a counter-clockwise direction to pull the air out of the box.
Place an incense in the bottom of the box on a small plate. Light the incense and smoke should begin to generate in the box. Turn the fan on slow speed to pull and circulate the smoke within the box. As the students look through the clear wrap, they should be able to see a small tornado form.