Beacuse you need something to support the rim. If you didn't have spokes, you'd have to have a solid disc. (well, maybe with some cutouts, like an alloy car wheel) and that'd be a lot heavier and more sensitive to side winds.
Spokes are found as part of wheels, for instance on a bicycle. They connect the hub to the rim.
Without spokes, wheels would have to be made from solid discs.
The wheels
"Spokes" are the things that branch out from the centre of wheels to the outside edge of the wheel, to stabilise them. So wagon spokes are the things that branch out of wagon wheel centres (usually wooden, in this case). Bicycle wheels also have spokes.
360 / 15 = 24 spokes
A hub is the center piece on your wheels that the spokes are connected to. it spins your wheels. if you dont know what spokes are they are the stick looking parts on your wheel.
"Spokes" are the things that branch out from the centre of wheels to the outside edge of the wheel, to stabilise them. So wagon spokes are the things that branch out of wagon wheel centres (usually wooden, in this case). Bicycle wheels also have spokes.
Bicycles need a reflector on the spokes of the wheels.
There are mainly two types of spokes used in bicycle wheels: straight-gauge spokes and butted spokes. Straight-gauge spokes are uniform in thickness throughout, while butted spokes are thicker at the hub and thinner at the rim. Butted spokes are lighter and more flexible, providing a smoother ride and better shock absorption. They also tend to be more durable and less likely to break compared to straight-gauge spokes. The choice of spokes can affect the overall performance of the bicycle in terms of weight, strength, and ride quality.
This completely depends on the wheel. The most common number of spokes per wheel is 36. Some better wheels have 32. Higher performance wheels have even less.
That would differ from one bike to another. A really small bike with maybe 12" wheels will have fewer spokes than a bike with 20" wheels. Say between 24 and 36.
There are mainly three types of spokes used in bike wheels: straight gauge, butted, and bladed. Straight gauge spokes are the most basic and durable, but heavier. Butted spokes are lighter and more flexible, providing a smoother ride. Bladed spokes are aerodynamic and reduce wind resistance, improving speed. The type of spoke used can affect the overall performance of the bike in terms of weight, flexibility, aerodynamics, and durability.