Ice skates ACTION 4Which simple machine helps skates grip the ice Ice hockey is an extremely fast-moving sport
The skaters move across the ice at lightning pace They are ice hockey players and the skates they wear allow them to move very quickly over the slippery surface and to grip the ice so they can turn and stop Special skates are used for different sports The blades of ice hockey skates are slightly curved to help players twist and turn Speed skaters wear skates with extra long blades to give them more pace Figure skaters use skates with a jagged front to the blade called a toepick that digs into the ice and helps jumping and footwork 5 Ice skating blades are a kind of wedge A wedge is a cutting machine Wedges are used to push and spread things apart The blades of a pair of scissors are wedges When they are closed tightly on a piece of paper they drive into the paper and tear it apart This is the cutting action Axes knives and saws are all wedges A saw is made up of a row of wedges called teeth The row of blades on the plough is formed from sharp wedges that cut and turn the soil ANSWER WEDGE (cid:2) (cid:2)
Sailboat ACTION 6What force powers a sailing boat Sailing boats use the power of wind to move through the water The wind pushes against a canvas sail that can be moved from side to side of the mast This movement allows the sail to catch the wind even if it isn’t coming directly from behind
7 The movement of our atmosphere powers sailing boats We call this movement wind and it can be very powerful When the wind pushes on sails it creates enough force to drive the boat forward Wind is created when air warmed by the Sun starts to rise from the land and sea It cools as it moves higher into the atmosphere Cold air is heavier than warm air so once cool it drops downwards again towards the ground This circular movement of warming and cooling air creates wind ANSWER WIND POWER WORKING PARTS Sailing boats have a streamlined hull That’s the part of the boat that cuts through the water The front or bow is shaped like a V which helps it push against the current Some boats called catamarans have two hulls side by side Attached underwater to the length of the hull is a fin-like centerboard or keel This makes the boat more stable and helps push it forward when the wind blows from the side sail mast rudder sternrising warm air falling cool air sea land position of keel
