Structure and Properties of Matter
Materials around us
Group materials by whether you can see through them, whether they dissolve in water, and whether they shine — and say what makes something matter.
Everything you can pick up is made of something: paper, wood, cloth, glass, metal, plastic, clay. Any substance used to make an object is called a material. Sorting objects into groups by a property they share has its own name — classification — and it is how the whole of this chapter works.
Seeing through things
Materials you can see through clearly are transparent, like window glass and air. Materials you can see through, but not clearly, are translucent, like butter paper and frosted glass. Materials you cannot see through are opaque, like wood and cardboard.
Disappearing into water
Stir sugar or salt into water and it vanishes: those are soluble in water. Stir in chalk powder, sand or sawdust and it is still sitting there however long you keep going: those are insoluble. Gases can dissolve too — oxygen dissolves in water, which is what fish depend on.
Have a play
How much of the shape behind each pane gets through.
Tap any part of the picture.
Worked example
A spoonful of sugar and a spoonful of chalk powder are each stirred into a tumbler of water. What happens, and what do we call it?
Stir the sugar and keep watching. The grains get smaller and then there is nothing left to see.
The sugar has not left the tumbler — taste the water and it is there. It has spread through the water so finely that you cannot pick it out.
Try it together
Now work out what "matter" means, starting from a school bag on a chair.
Madam Vidya asks the class to put their bags on their seats, then to sit down. They cannot.
1.The children cannot sit because the bag has taken up something the child needs. What has it taken up?
Have a go
Have a go on your own. The space that matter occupies has a one-word name, measured in liters and milliliters. What is it?
Ready to practice?
Eight questions on what you have just read. Nothing is timed, and you can play as many times as you like.