Why does a dome form on a coin when you pipette water on
it drop by drop?
Water is a polar molecule-that is it has a negatively charged end and a
positively charged end. The negative end of one water is attracted to the
positive end of another and they stick together tightly. So when you drop
water on a coin the molecules of water in the new drop stick to the water
droplets in the old drops until gravity overcomes the electric forces. How
many drops can YOU pile on a coin before it spills over?