01:30Can you see the grey box? Sensory adaptation explained by Kit Yates #sciencedemo #optical #sensory
The Royal Institution
This is the VOA Special English Agriculture Report, from http://voaspecialenglish.com Florida, in the southeastern United States, is called the Sunshine State. It grows more oranges than anyplace except Brazil. But in January, extremely cold air damaged some Florida oranges and strawberries and killed fish at tropical fish farms. The unusually long period of cold weather has shown how even warm climates can sometimes freeze over. But protecting plants and trees in the garden may not be too difficult if you follow a few suggestions. Sudden cold can be the biggest threat, especially after a warm period. Plants have not had a chance to harden their defenses. Those that are actively growing or flowering are at high risk. Try to choose plants that live best with cold weather, and plant them in areas that face west and south. Being near other growth may also provide warmth. Most frost damage takes place at night. Ice crystals form on the leaf surface. They pull moisture from the leaves and keep plant tissues from getting water. Cold weather is most likely to damage or kill plants that do not have enough moisture. So keep the garden watered. Moist soil absorbs more heat than loose, dry soil covered with mulch or vegetation. University of Arizona extension experts say covering plants and small trees with cloth or paper can help prevent frost damage. A one-hundred watt light bulb designed for outdoor use can also provide warmth. Some people place Chris
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