3 Raft Pogo Zorb Roller coaster Glossary Index Credits 36 38 40 42 44 46 48 lever piston gravity Momentum Lots of different kinds of machines are used for sport Usually sport machines are designed for just one or two people to use We use machines for sport on land on the water and in the air Some are simple machines such as the blade of a skate Others such as a skidoo are more complicated but all our sport machines need energy and power The energy these machines use may be chemical energy from fossil fuels such as gasoline or human energy in our body It can be energy from the movement of air in sails or that produced in an engine Now let’s look at some of the machines that allow us to enjoy sport and the science that makes this possible
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)
