If we have to touch the dry ice, we put on the glove or oven mitt. old dish towel and hammer This is for breaking up the dry ice if it comes in a large chunk. Use the meter or yard stick to measure and mark each item before you cut. Step 1: Cut the four sides of the simulator chamber.
If the piece of cardboard is big enough, you can make all sides in one piece, then score the corners so that they can be bent to form a 90 degree angle. The slit should begin about 2" up from the bottom, and end about 2" down from the top. It should be positioned about 3/4-1" from the corner. The windows can start 2" to 3" above the bottom and end the same distance from the top. The size of the windows is not critical, but allow enough of a cardboard "frame" so that it will still stay flat and strong. These sides will be adjacent to (next to) one another, not on opposites sides of the chamber. Step 4 Lay the four sides out like the diagram below and tape three corners together with duct tape. Important: note the position of the slits on each side.
Step 5 Paint the inside surfaces with black paint and let them dry thoroughly. You can duct tape them to either the inside or the outside of the simulator. Step 7 Tape the fourth side of the model so it creates a box with no top, no bottom, 4 slits, and two windows. Step 1: If the dry ice is in a big chunk, wrap it in the dish towel placed on a hard but unimportant surface, and tap it with a hammer until you hear it crack. If the dry ice is the cylindrical kind, leave the pieces whole. Place the prepared chunks or dry ice pieces in the cooler. Its temperature is -109.3°F, and if you touch it more than a second or two it will freeze your skin cells. This leaves a burn injury similar to that of touching a hot iron. Parents should supervise their children when dry ice is used, and never leave it unattended if young children are present. Step 2: Place hot plate on a firm surface, plug it in and turn it on high. Step 3: Place a pan of hot water onto the hot plate and bring it to a boil Step 4: Position the simulator chamber over the hot plate with one window facing towards you and one window facing towards the side. In the photo, Aimee is behind a model that is already set up. Important note: if you want cyclonic rotation, position the chamber with the slits on the right side as they face you. Step 5: While the water is heating, position the light source so that it shines through the side window and lights up the interior of the simulator chamber. Step 6: When the water boils it will create water vapor (steam), and the vortex will form. Lift the edge of the chamber, and using the tongs, carefully place a chunk of dry ice into the boiling water. The combination of boiling water and dry ice creates a dense white vapor, making the already-present vortex circulation visible. Refresh the water in the pan with more hot or boiling water and you can keep the vortex going easier--cold water will cool it down too much. When the dry ice has evaporated, replace with another chunk. If you are using the smaller pieces of dry ice, you will need to put about 1/4 cupful at a time. Experiment with the amount of dry ice versus the amount of water in the pan to find the right balance. In our experience, a large pan tends to make the vortex wander around. In the course of wandering, it steams up the plastic windows.
Trying different size pans will let you refine the system. It is actually harder to make a tornado model visible than it is to make the simulator in the first place. You can create the vortex circulation without dry ice, but the dry ice makes it far more visible. A bright light shining directly down into the box can make it easier to see. The light cannot be too close to the top of the box, however, or you will block the rising air. Many more tips and hints will be given in the Secrets of the Tornado video, as well as several more models. You might first experiment with the width of the slits. Start by making them 1 1/2 inches wide, then use masking tape to make the slits 1 inch wide, then 1/2 inch wide, then 1/4 inch wide and see what this does to the shape and speed of the vortex. Another experiment can be done by completely blocking up part of the slit vertically. For instance, try covering up the upper half of the opening, then try covering up the middle third of the opening, then try covering up the bottom third of the opening.
All of these will somehow change the character of the vortex. I can't tell you exactly how, because you may not be using the same brand of hot plate or the same shape pan we are using. Each combination of "variables" affects the outcome.