PSLE Science cheat sheet
PSLE Science · Keep the key ideas within reach.
Science
A living thing must show all life processes: it needs air, water and food, moves or grows, responds to changes, and reproduces; a non-living thing lacks at least one of these.
Classification key rule: at each step use one feature with only two possible answers (yes/no). Stop when each group holds a single kind of object.
States of matter: solids keep their own shape, liquids take the shape of the container and keep a level surface, gases fill the whole container and can be compressed.
Melting and boiling are changes caused by heating; freezing and condensation are changes caused by cooling. Water boils at 100 degrees Celsius and freezes at 0 degrees Celsius at sea level.
Condensation explains droplets on a cold glass: water vapour in the air cools and turns back into liquid water.
A force is a push or a pull. Forces can make an object start moving, stop, change speed, change direction, or change shape.
Friction acts opposite to motion; rough surfaces increase it and smooth or lubricated surfaces reduce it. Friction produces heat.
A magnet attracts only magnetic materials (iron, steel, nickel) and has two poles; like poles repel, unlike poles attract, and a freely hanging magnet points north-south.
Light travels in straight lines. Shadows form when an opaque object blocks light; a transparent object lets most light pass, a translucent one lets some through.