[Music] hi and welcome back to free science lessons by the end of this video you should be able to describe the physical separation technique simple distillation in the last video we looked at how we can use crystallization to separate a dissolved solid from a liquid in this example we have a solution of sodium chloride in water and remember that a solution in water is called an aquous Solution by gently heating this solution we can evaporate the liquid in this case the water and when the water evaporates we're left with crystals of the solid which in this case is sodium chloride so crystallization is a great way of separating a dissolved solid from a liquid now there is a problem here what if we want to separate a dissolved solid from a liquid but we want to keep the liquid well in this case we use Simple distillation now I should point out that there's another type of distillation called fractional distillation and we're going to be looking at fraction distillation in the next video okay now simple distillation consists of two stages first we evaporate the liquid by heating this turns the liquid into a vapor next we condense the Vaper back to a liquid by cooling I'm showing you here The Operators that we used to carry out simple distillation first we place our solution with the liquid and dissolved solid into the flask the flask is connected to a continuous glass tube which I'm showing you with the yellow arrow the glass tube is surrounded by a jacket called the condenser cold water from the top continuously runs through the condenser so the condenser keeps the internal glass tube cold after running through the condenser the tap water simply goes down the sink we also have a thermometer as part of the apparatus so let's see what happens during simple distillation we we start by heating our solution for example by using a bunson burner as we heat the solution the liquid starts to evaporate turning into a vapor The Vapor now Rises up the glass tube as the vapor passes over the thermometer the thermometer reading increases usually with simple distillation we Heat this solution until it boils next The Vapor passes into the condenser remember that the condenser is cold because we're Circ ating cold tap water around it this causes the vapor to condense turning back to a liquid as it passes through the condenser and we can collect the liquid in the beaker so at the end we're left with crystals of our solid in the flask and our liquid in the beaker now simple distillation can be used to produce drinking water from sea water however a great deal of energy is required for simple distillation so generally it's not used to produce drinking water other techniques are used instead you'll find plenty of questions on this topic in my vision workbook which you can get by clicking on the link [Music] above