Yogurt stands in for mayonnaise, and veggies such as celery, onions or bell peppers add a bit of crunch. One serving of egg salad made with two egg whites, 1/2 ounce of plain, fat-free yogurt and 1/4 stalk of celery has 60 calories, less than 1 gram of carbohydrates and 0.5 grams of fat.
The Amazing Inventions of Heron of Alexandria. Heron, also known as Heron of Alexandria, developed many machines and mechanical devices with practical uses, showing that it was possible to take theory and put it into practice. Some of his devices were: 1  A coin operated 'Holy Water Dispenser'. 2  A water organ. 3  The Aeolipile, a steam-powered device.
The most important invention of the Renaissance, and perhaps in the history of the world, was the printing press. It was invented by German Johannes Gutenberg around 1440. By 1500 there were printing presses throughout Europe.any of the great scientific discoveries made during the Renaissance were in the area of astronomy. Great scientists such as Copernicus, Galileo, and Kepler all made major contributions. This was such a big subject that we devoted an entire page to it. Learn more about it at our page on Renaissance Astronomy.