9781422282908

6

S T E M I N C U R R E N T E V E N T S

INTRODUCTION Finding Energy

W hen coldweather comes,you’re probably able tomake yourself comfortable indoors by turning up the thermostat. Within seconds, the furnace kicks into action, burning a fuel such as natural gas or heating oil. Energy stored in the atoms of the fuel is released and turned into heat, which soon reaches you and takes the bite off that cold day. Energy exists in different forms all around us, and for hundreds of thousands of years, humans and their ancestors have sought to use that energy to make life easier for themselves.Energy provides warmth, fuel for cooking, and electricity to power our smartphones and other gadgets.Energy also propels vehicles, from scooters to mammoth ships to spacecraft that explore the planets. Modern life as we know it would not be possible if humans hadn’t discover ways to convert the energy all around them into forms that they can use. One of the first great human inventionswasmaking controlledfires to provide heat, cook food, and keep

away dangerous animals. Fires occur naturally, of course, as when lightning strikes spark forest fires. Even heat from the sun can cause a wildfire.But building controlled fires,with grasses and then wood for fuel, led to great improvements for people. Energy fromthe sun (solar power) was another natural force humans learned touse to their advantage.They positioned their homes so that inwin- ter they could get as much heat from the sun as possible.Animalswere also a source of energy, whether used to pull a cart or turn the wheels of mill that ground wheat into grain. The energy sources of today’s world can be more complex, thanks tothedevelopmentsmade intheSTEM fields over the last several hundred years. During the 19th century, the creation of an engine powered by burning gasoline, and the discovery of vast amounts of petroleum, led to the dominance of the car as a source of transportation. Today, more than one billion cars travel the world’s streets, along with trucks, buses, and