two glass bulbs connected by a narrow neck the bottom bulb generally larger than the top a thin stream of sand or other material flowing through the neck a frame or stand to hold the two bulbs in place a stopper at the neck to control the amount of material flowing through
hourglass which has two glass bulbs connected by a narrow neck hourglass which has the bottom bulb generally larger than the top hourglass which is a thin stream of sand or other material flowing through the neck hourglass which is a frame or stand to hold the two bulbs in place hourglass which is a stopper at the neck to control the amount of material flowing through