Drought is a universally understood phenomenon — especially here in the arid Southwest. But what does drought really mean? To help define the term, and the concept, scientists use several commonly used drought indices. Each summarizes thousands of data points on rainfall and other information into a single handy number.
In 1986, after a statewide vote by thousands of school children, the Arizona Tree Frog became Arizona’s official state amphibian. Beating out better-known rivals like the spadefoot toad by a wide margin, this small and seldom-seen frog might seem an unlikely candidate for top spot. But it makes sense when you realize how much they love to climb.
Rarely more than two inches long, with smooth green skin and a dark stripe running from eye to rear, these amphibians live mostly above 5,000 feet in the forests of central-northern Arizona, close to streams and wet meadows.
This week Earth Notes concludes its series on the sun with a look at how to use a backyard solar oven. You can use one anywhere there’s a few square feet of sunny exposure on a backyard or balcony.
And yes, you can use a solar oven on some winter days. Even when it’s cold and the ground is covering with snow, a cooker will work if you have enough sunshine and your solar oven is well insulated. But you’ll need to use the midday hours when the sun is at least 45 degrees above the horizon—that means your shadow is shorter than your height.
This week Earth Notes continues its series on the sun, with a look at turning your backyard into a kitchen
Just as the inside of a parked car heats up on a sunny day, a solar cooker traps the sun’s rays in its enclosed interior, causing water, fat and protein molecules in the food to heat up. The molecules vibrate vigorously, and the food cooks.