Simple machines for grade 4

Simple machines for grade 4

• 3.
  Lever  It isa long rod that can be used to cut things, move heavy objects, or open tins.  for example :hammer, bottle-opener, a pair of Scissors etc.
• 4.
   A pulleyis made up of a grooved wheel and a rope. It is used to lift loads. Machines such as cranes and sailboats make use of pulleys.
• 5.
  Wheel and Axle Wheeland axle is made up of a wheel through which a rod is called axle passes. Such a combination helps to move objects or change their direction.  Machines such as cars, roller skates and door knobs make use of wheel and axle.
• 6.
  Inclined Plane Inclined planeis used to lift heavy loads to a height easily. An inclined plane makes movement easier. Some examples are ramp , slanted road , path up a hill , slide etc.
• 7.
  WEDGE A wedge isa simple machine used to push two objects apart. A wedge is made up of two inclined planes . These planes meet and form a sharp edge. This edge can spilt things apart. Some examples are knives, axes, forks, nail ,etc.
• 8.
  Screw A screw hasridges and is not smooth like a nail . Screws are also used to hold objects together. They are used in key rings , bottle caps , fountain pen caps, etc.
• 9.
  Whenever you pickup anything heavy, your elbow acts as the fulcrum of the lever, and your arm bone acts as the lever itself.  Natural body levers first developed in fish around 440 million years ago.  people used the lever in some form, for moving heavy stones or as digging sticks for land cultivation.
• 11.
  Questions
• 12.
  Fill in theblanks. ----------------- is a wheel and axle.  A well is a --------------. A ---------------- is made up of a grooved wheel and a rope. Ramp is a example of --------------- Roller skates are example of --------------- Wheel barrow is an example of ------------