Year 5 have had great fun in Science this week whilst investigating how they can separate a mixture of a liquid and different solid particles. As part of their topic about the properties and changes of materials, the children have learnt about the properties of solids, liquids and gases, and the process of dissolving. This week they were presented with a rather unappetising concoction known as ‘Alien soup’. The recipe specified that it contained gravel, sand, split pins, water and salt. The chef, however, could not be sure whether or not they had used sugar instead of salt by mistake. The childrens’ task was to separate all the individual ingredients so that they could identify if salt or sugar had been added. Firstly, they sieved the mixture to separate the gravel, then used a magnet to separate the split pins. Next, they used filter paper in a funnel to separate the sand. All that remained was the water and dissolved salt or sugar. Using their knowledge of dissolving, the children worked out that if they evaporated the water, the dissolved solid would be left behind for them to identify. Finally, the water evaporated leaving behind large crystals of what turned out to be salt – much to their disgust!
