Fill the pan with 1/2 cm of warm water. Make sure that the water is not cold, room temperature or extremely hot or the model will not work properly. Use the ruler to make sure you have the right amount.
Place the eraser in the center of the pan. Use the rectangular type eraser with flat sides and place the eraser so that it is lying flat and the top portion is sticking out of the water. When the eraser is in place, put ten grains of salt on the top portion of the eraser. Do not let any salt fall in the water and spread the grains out rather than making a pile.
Flip the glass upside down and slowly place it over the eraser, being careful not to knock any salt into the water below. Press the glass down through the water and let it sit at the bottom of the pan. Note the time that you did this step as you will need to check back on the project periodically.
Observe the glass after five minutes. You will begin to see some of the water evaporating into the glass and a mist beginning to form. Check back in on the experiment every five minutes to see clouds beginning to form. After 20 minutes, a small cloud will be floating in the top of the glass.