There are four important warning signs that should prompt you to talk to a health care provider. 1  Pain. Pain from arthritis can be constant or it may come and go. 2  Swelling. Some types of arthritis cause the skin over the affected joint to become red and swollen, feeling warm to the touch. 3  Stiffness.
There's a whole lot of water on Earth! Something like 326,000,000,000,000,000,000 gallons (326 million trillion gallons) of the stuff (roughly 1,260,000,000,000,000,000,000 liters) can be found on our planet. This water is in a constant cycle -- it evaporates from the ocean, travels through the air, rains down on the land and then flows back to the ocean.
Oceans cover approximately 70.8% or 361 million square kilometers (139 million square miles) of Earthâs surface (Table 8o-1) with a volume of about 1370 million cubic kilometers (329 million cubic miles). The average depth of these extensive bodies of sea water is about 3.8 kilometers (2.4 miles). Maximum depths can exceed 10 kilometers (6.2 miles) in a number of areas known as ocean trenches. The oceans contain 97% of our planet's available water.