Top 10 Structurally Amazing Bridges

Bridges have been around ever since humans began to move themselves -- and their goods -- from one place to another. Early bridge engineers had to do little more than fell a tree across a ravine or stream, but they soon discovered that they could span greater distances and haul heavier loads by putting more time and energy into their structures. Roman engineers perfected the stone arch and used it to buildaqueducts -- bridges that conveyed fresh water great distances -- and similar structures to carry traffic across streams and rivers. But the Industrial Revolution took bridge building to new heights and even greater lengths. By the end of the 19th century, record-breaking bridges seemed to come fast and furious. The Brooklyn Bridge, completed in 1883, was the longest spanning bridge in the world -- until Scottish engineers completed the Firth of Forth Bridge just seven years later. A new century brought longer, more amazing bridges. In 1937, the Golden Gate Bridge stretched its 8,981-foot (2,737-meter) back over the treacherous waters of the San Francisco Bay. Today, engineers continue to test the limits of science and imagination. They experiment with innovative materials, designs and methods of construction. Their finished products move cars and trains. They also move people's souls. What follows is a survey of some of the most breathtaking bridges of the modern era. We've limited ourselves to just 10 bridges, but not to any particular region of the world.

5 Ways Modern Car Engines Differ from Older Car Engines

Compared to other technologies we use every day, it seems like car engines haven't really changed much. The engine in an old Ford Model T has plenty in common with the engine in a 2011 Ford Fusion, but it's doubtful Alexander Graham Bell would know what to do with an iPhone. While communications technology has changed drastically, car engines use the same basic principle: The combustion of air and fuel to create rotational force and move a car.

But while the same basic principles that drove the first car engines are still used today, modern car engines have evolved to meet the power and efficiency needs of today's drivers. Think of older car engines as wolves and modern car engines as dogs. They're share the same heritage and have similar characteristics, but one does just fine in everyday modern situations, while the other just couldn't adapt to living in a city or suburb.
Before we talk about how modern car engines are different from older ones, you need to understand the basics of how a car engine works. Basically, gasoline and air are ignited in a chamber called a cylinder. In the cylinder is a piston that gets moved up and down by the gasoline/air explosion. The piston is attached to the crankshaft. As the piston moves up and down, it makes the crankshaft rotate. The crankshaft goes out to the transmission, which transmits that power to the car's wheels. Sounds simple, right? With modern engines the basics still apply, but there's a lot more to think about.