A pulley is a simple machine that uses grooved wheels and a rope to raise or lower a load.
Lets try it using a milk jug and a pulley and some rope.
Have students lift a milk jug with some dirt in it just attached to a rope. Have them write in their journal what that was like. Then have the students use a fixed pulley to move the jug. Have them write if that was easier or harder. Then have the students use a movable pulley.