KS3 Science (All)

• friction


  occurs between 2 objects when one or both are moving
• gravity


  a pull towards the earth
• magnetic


  act over short distances
• what is friction


  a contact force, a force that slows moving objects
• friction useful for


  writing, walking
• friction not useful for


  reduces speed, causes wear and tear
• contact force


  acts on a point of an object by direct contact
• non-contact

  applied by another body that's not in direct contact
• calculation of pressure


  force/area
• lubricants can...


  reduce friction, reduces noise
• type of lubricant


  oil
• word equation for photosynthesis

  carbon dioxide + water -> glucose +oxygen
• a plant needs to grow where there is ....

  sun and water
• cell membrane


  controls what goes in and out of the cell
• cytoplasm


  jelly-like substance where chemical reactions happen
• nucleus


  controls what happens inside the cell
• chloroplast


  where photosynthesis happens
• vacuole


  contains a liquid called cell sap, keeps the cell firm
• cell wall


  made up of a substance called cellulose, supports the cell
• the skeletal system has 4 functions

  support, protection, movement, blood cells
• muscles can only...


  pull
• a muscle is made up of tiny strand called...

  fibres
• a pair of muscles

  antagonistic muscles
• types of rocks


  sedimentary, igneous, metamorphic
• igneous rocks


  basalt, granite
• sedimentary


  chalk, limestone
• metamorphic


  slate, marble
• fossils


  preserved remains of a dead organism