Place a pyrex glass funnel with its mouth down in a saucepan full of water, in such a way that the stem tube of the funnel is above the water or pointing upwards into air. Rest the edge of the bottom portion of the funnel on a nail or a coin so that water can get under it. Place the pan on the stove and heat it till it began to boil. Where do the bubble form first?. Why?



It form inside of pyrex glass tube