Question 29
What Makes It Muggy? Like the heat index, muggy is a “feels-like” condition, except it has to do more with how “breathable” the air feels than how hot it feels. The muggier the weather, the less chance you’ll feel cool because of decreased evaporation rates, which is why the following weather conditions are notoriously linked to the muggiest of days and nights: Warm air temperatures, generally of 70°F or above (the warmer the air, the more moisture it’s able to hold); High moisture (the more moisture there is in the air, the “heavier” it feels); and Low winds (the less wind there is, the fewer air molecules there are passing over your skin evaporating and cooling you off). Since mugginess expresses how moist the air feels, you might think that relative humidity would be a good indicator of how muggy it feels outside. However, dewpoint temperature is a better measure of mugginess. Why? Dew point not only gives you an indication of how moist air is, but how warm it is as well (since dew point temperature can go as high as, but never higher than the actual air temperature). So if the dew point is high, it means both air moisture and temperature probably are, too.
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Question 30
The area that is now South Africa has been inhabited by humans for millennia. The San, the original inhabitants of this land, were migratory people who lived in small groups of about 15 to 20 people. They survived by fishing and hunting and by gathering roots and other wild foods. They did not build permanent dwellings but used rock shelters as temporary dwellings. Around 2,000 years ago Khoikhoi pastoralists migrated to the coast. In the eastern part of present-day South Africa, iron-working societies date from about 300 AD. The Sotho-Tswana and Nguni peoples arrived in this region around 1,200 AD. They lived by agriculture and stock farming, mined gold, copper, and tin and hunted for ivory, and built stone-walled towns. Over the centuries, these societies had diverse contacts with the Khoisan. Strife between the San and the Khoikhoi developed over the game competition; eventually, the Khoikhoi became dominant. These peoples lived in the western part of present-day South Africa and are known collectively as the Khoisan.
