How Cars Work · Stopping and Steering
Putting your back into it
In an old car — really old, before about the 1960s — there was no help with steering. The driver had to provide all the muscle to push the front wheels into a turn, especially when the car wasn’t moving. Parallel parking an old car without help is a workout. You are literally pushing two heavy wheels sideways through gravel or asphalt.
Modern cars use power steering, which uses either hydraulic pressure or an electric motor to assist the driver. In a power-steering car, even a kid could turn the wheel of a parked car with one hand. Without it, even an adult has to lean into it.
Many 1960s American cars came with power steering as an option. By the 1980s it was standard on most cars. By the 2010s, almost all of it had switched from hydraulic to electric. We will meet electric power steering in Part 2.
Did You Know? In Formula 1 racing, where cars routinely brake from 200 miles per hour down to 50 in a few seconds, the brake discs glow orange-red after every hard braking — visibly hot at night. Each disc can briefly hit 1,800°F, hotter than lava. Race teams use brake discs made of carbon-ceramic, a special material that can survive temperatures that would melt steel. Even with that material, the discs slowly wear away through a season of racing — the kinetic energy of every braking corner has to go somewhere, and a tiny amount of disc material goes with it as smoke and dust each time the brakes are used.
End of Part 1
That is the entire mechanical car. Engine making power through controlled explosions; carburetor mixing fuel and air; ignition system making the spark; transmission and drivetrain getting the power to the wheels; brakes and steering controlling where the car ends up.
Put all of that together, and you have a 1960s car. The kind your grandparents drove. Every part of it is a piece of metal pushing or pulling another piece of metal, in ways you could see and touch if you took the car apart. No software. No computers. Just physics, levers, gears, and gasoline.
Then, sometime in the 1970s and 1980s, things started to change. The first small computers appeared under the hood, doing one job each. The mechanical parts didn’t go away — they are still there, even in the newest cars on the road today — but they got managers. Sensors watching them. Software adjusting them in real time. And new systems started showing up that the mechanical parts could not do alone: brakes that don’t lock up in a panic stop, fuel mixtures that change with the weather, computers that watch the road and pull the steering wheel for you if you’re about to drift out of your lane.
That is Part 2.
Questions to talk about
No answer key. These are for arguing over, with someone who read the same chapter.
- Kinetic energy depends on speed squared, so doubling your speed quadruples it. Explain to someone why that means a car at 60 needs four times the stopping distance of a car at 30 — not twice.
- Brakes work by deliberately turning useful energy into waste heat. Does that strike you as a clever solution or a crude one? Keep the question in mind — Chapter 11 comes back to it.
- The chapter says energy cannot be created or destroyed, only moved around. Trace the energy in a car from the petrol station to a stop sign. Where does each bit end up?