Final answer:
Wind is the element of weather that is caused by a difference in air pressure between two air masses, often depicted as high (H) and low (L) pressure areas on weather maps with isobars. Low-pressure systems can lead to a variety of weather events, including severe storms and tornadoes.
Step-by-step explanation:
The element of weather that is caused by a difference in air pressure between two air masses is wind. This is because the atmosphere's pressure plays a crucial role in shaping weather patterns. For instance, when the barometric pressure is high, the air will naturally move towards areas of lower pressure. The greater this difference in pressure is, the more intense the winds that will develop. Such winds can sometimes lead to the formation of severe weather phenomena, including tornadoes, which are violent rotating columns of air that reach from a thunderstorm down to the ground.
In weather systems, low-pressure systems are often associated with more tumultuous weather. These occur when the earth's surface atmospheric pressure is lower than its surroundings, leading to the rise of moist air, which condenses to form clouds and instigate weather events. Meteorologists often monitor these pressure differences using weather maps, which depict regions of high (H) and low (L) pressure with isobars—lines representing places of constant pressure.