This causes high pressure. Therefore, high pressure areas are areas of descending air , air moving downward, because it is denser and heavier. This is what creates the area of high pressure. Fluids tend to move from areas of abundance to areas of deficits - think of siphoning gas from a car. The difference in pressure between two locations is called a pressure gradient , and a pressure gradient force will cause air to move from high pressure to low pressure.
Wind direction is measured with a wind vane.
Remember, winds are always named after the direction from which they are coming . Hence, an southeasterly wind describes winds coming from the southeast. Speed is measured with an anemometer , a device with cups that turn during a wind. The faster the rotation the more electric current is generated, which is then converted to mph. Land and Sea Breezes These are excellent, simple examples of the effects of unequal heating.