TECHGUIDANCES

Doesn’t the east coast of South America fit exactly against the west coast of Africa, as if they had once been joined? This is an idea I’ll have to pursue.” – Alfred Wegener said to his future wife, in December 1910. We can’t really get into Alfred Wegener’s head, but …

During World War II, battleships and submarines carried echo sounders to locate enemy submarines (Figure below). Echo sounders produce sound waves that travel outward in all directions, bounce off the nearest object, and then return to the ship. By knowing the speed of sound in seawater, scientists calculate the distance …

How Plates Movem : If seafloor spreading drives the plates, what drives seafloor spreading? Picture two convection cells side-by-side in the mantle, similar to the illustration in Figure below.  Hot mantle from the two adjacent cells rises at the ridge axis, creating a new ocean crust.  The top limb of …

Introduction Why is Earth the only planet in the solar system known to have a life? The main reason is Earth’s atmosphere. The atmosphere is a mixture of gases that surrounds the planet. We also call it air. The gases in the air include nitrogen, oxygen, and carbon dioxide. Along …

The sun is always up, even in the middle of the night in Antarctica during the summer. The photo on the left is Antarctica during the night in the summer. The photo on the right is of Antarctica during the day in summer. Similarly, in the winter Antarctica is mostly …

When Columbus sailed the ocean blue, and for centuries before and after, ocean travel depended on the wind. Mariners knew how to get where they were going and at what time of the year based on experience with the winds. Winds were named for their usefulness to sailors, such as …

Children in Punta Arenas, Chile, the world’s most southern city, look forward to spring as much as anyone who lives through a frigid, dark winter. But some years, the children are instructed not to go outside because the ozone hole has moved north and the UV radiation is too high. …

No one can predict exactly when a volcanic eruption will take place. There are clues, but no one knows exactly when. Sometimes a volcano will erupt when scientists are studying it. Volcanologists have a high fatality rate among scientists because forecasting eruptions is so difficult. Predicting Volcanic Eruptions Volcanic eruptions …

Weather forecasts are better than they ever have been. According to the World Meteorological Organization (WMO), a 5-day weather forecast today is as reliable as a 2-day forecast was 20 years ago. Now there’s no excuse to be rained out on a picnic! The most accurate weather forecasts are made …

After the sun’s energy enters the Earth’s atmosphere the heat is either absorbed—(taken in, reflected—hitting a barrier and bouncing off), or scattered—(hitting a barrier and bouncing off in many different directions). The heat left on Earth is equal to the amount of heat absorbed minus the amount of heat given …