revision science

when is water said to be hard

• when it lathers redily with soap

• when it turns to ice block

• when it does not lather redily with soap

• when it starts to sing

what is rarefraction

• the change of speed and direction of light

• when it rarefracts

• when it bends

• when blows up

what is the law of gravity

what is the main soure of enrgy

• Sun

• MOON

• PS4

• LIGHTNING

WHICH IS A TYPE OF POLLUTION

• AIR

• LIFE

• MUSICAL

• TEETH