Natural Sciences and Technology Grade 6 Term 2: Matter and Materials Dissolving

The difference between melting and dissolving Topic 4 Dissolving The difference between melting and dissolving Gr 6 Natural Sciences and Technology – Term 2, Topic 4

What is melting? [1] In science: melting involves one substance; the liquid and the solid are the same material; and heat is required for a solid to melt. Gr 6 Natural Sciences and Technology – Term 2, Topic 4

What is melting? [2] When heated: the particles of the solid material are freed up; the forces holding the particles are not so strong; and the solid material becomes liquid. Gr 6 Natural Sciences and Technology – Term 2, Topic 4

What is melting? [3] When cooled: the particles of the liquid move closer together; the forces between the particles become very strong; and the material reforms into a different, solid shape. Gr 6 Natural Sciences and Technology – Term 2, Topic 4

What is dissolving? [1] In science: dissolving involves two substances; the substances are called the solute and the solvent; the solute is the substance which will be dissolved (e.g. sugar); the solvent is the substance doing the dissolving (e.g. water). Gr 6 Natural Sciences and Technology – Term 2, Topic 4

What is dissolving? The solute and the solvent are evenly mixed together; and the particles of the solute move into the solvent to form a solution. Gr 6 Natural Sciences and Technology – Term 2, Topic 4

Important scientific facts In science: although we can no longer see the sugar (solute) once it has dissolved in water, IT IS STILL PRESENT.  many people think that the sugar (solute) has disappeared because it is not visible in the water,  BUT, THIS IS NOT TRUE. the sugar is still present in a sugar water solution. It has just been broken down by the water molecules.  Gr 6 Natural Sciences and Technology – Term 2, Topic 4

What is the difference between melting and dissolving? Can you explain in your own words what the difference is between melting and dissolving? Melting is ... Dissolving is ... Ask learners if they remember the differences between melting and dissolving Gr 6 Natural Sciences and Technology – Term 2, Topic 4