According to UCAR, Center for Science Education, to make a tornado model you need an 8-ounce jar with a lid, water, vinegar, clear liquid dish soap and a pinch of glitter. UCAR provides instructions for constructing the model.
First, fill the jar three-quarters full of water. Next, add in 1 teaspoon of vinegar and 1 teaspoon of clear liquid dish soap. Then, add a pinch of glitter. Lastly, close the lid and twist the jar to swirl the contents. A vortex like the swirling winds of a tornado forms in the center of the jar. Due to the water's friction against the glass wall, when the jar is being twisted, the water inside against the glass is pulled along while the fluid on the inside takes longer to move. Eventually, both the glass jar and the contents spin as you rotate the jar. However, when you stop rotating the jar, the contents inside continue to spin. A small tornado can be seen for a few seconds when the outer fluid slows down and the inner fluid continues to spin rapidly. While real tornadoes happen in the air, this vortex is made in water. However, both air and water are fluids and move in similar ways, as stated by UCAR.