Set the bowl in the middle of the tub of seawater and then cover the tub with the plastic sheet. In the middle of the plastic sheet put the coin so the center of the plastic sheet is lower at that point. Be sure the bowl is below the penny! Now set it out in the sun so the sea water can evaporate. When it evaporates the water goes into the air as fresh water. Some of it will condense on the underside of the plastic sheet and flow down to the center, which is lower. As it collects in the center it will drip down into the bowl and you will have a bowl with fresh water in it!