Marriage in NISA essays

Marriage in NISA essays Marriage in Nisa: The Life and Words of a !Kung Woman Marriage is something that is sacred in all cultures. Everyone gets married in some way or another. In American culture, a man marries one woman, and together, they eventually raise a family. In some places, marriages are arranged. There are other places where people marry their cousins and others where men marry more then one woman. All of these types of marriages are discussed in Anthropology: An Applied Perspective. Many different cultures have many different ways to go about marrying and having families. In Nisa: The Life and Words of a !Kung Woman, Nisa speaks of her many marriages and how they worked out and why they turned out that way. Nisa was married for the first time at a very young age. She had not even menstruated yet. That is the way that it is in her culture. A woman marries an older man when she is very young. Often, the girl is frightened to stay in their new home alone together right away, so a nurse comes and stays with them for a short period of time. Nisas marriage ceremony was very different from a marriage ceremony that we would have here in America. The women wear beads and decorations, like we do, but that is only part of the ceremony. A main part of the marriage is that the husbands family and the wifes family band together and make a marriage hut for the new couple. Here is where the two are supposed to live and sleep together. Very rarely does a young girl actually stay in the hut at night though. Nisa ran back to her parents hut everytime that her husband would fall asleep. Nisa also had many husbands. Which is normal in her culture. Polygamy is also normal. Men are aloud to marry more then one woman, but often it does not work out. Nisa was going to marry a man that had another wife, but it did not feel right to her so she did not do it. The !Kung people call their multiple wives, co-wives. In many instances, the first ...

How the Drinking Bird Science Toy Works

How the Drinking Bird Science Toy Works The drinking bird or sippy bird is a popular science toy that features a glass bird that repeatedly dips its beak into ​the water. Heres the explanation for how this science toy works. What Is a Drinking Bird? Depending on where you live, you may see this toy called a drinking bird, sipping bird, sippy bird, dippy bird or insatiable birdie. The earliest version of the device appears to have produced in China circa 1910-1930. All versions of the toy are based on a heat engine in order to function. Evaporation of a liquid from the birds beak lowers the temperature of the head of the toy. The change in temperature creates a pressure differential inside the body of the bird, which causes it to perform mechanical work (dip its head). A bird that dips its head into water will keep dipping or bobbing as long as water is present. In fact, the bird works as long as its beak is damp, so the toy continues to function for a span of time even if it is removed from the water. Is the drinking bird a perpetual motion machine? Sometimes the drinking bird is called a perpetual motion machine, but there is no such thing as perpetual motion, which would violate the laws of thermodynamics. The bird only works as long as water is evaporating from its beak, producing an energy change in the system. What Is Inside a Drinking Bird? The bird consists of two glass bulbs (head and body) that are connected by a glass tube (neck). The tube extends into the bottom bulb almost to its base, but the tube does not extend into the top bulb. The fluid in the bird usually is colored dichloromethane (methylene chloride), although older versions of the device may contain trichloromonofluoromethane (not used in modern birds because it is a CFC). When the drinking bird is manufactured the air inside the bulb is removed so that the body will fill with fluid vapor. The head bulb has a beak that is covered with felt or a similar material. The felt is important for the functioning of the device. Decorative items, such as eyes, feathers or a hat may be added to the bird. The bird is set to pivot on an adjustable crosspiece fixed to the neck tube. Educational Value The drinking bird is used to illustrate many principles in chemistry and physics: boiling and condensation [dichloromethane has a low boiling point of 39.6 Â °C (103.28 Â °F)]combined gas law (​the proportional relationship between the pressure and temperature of a gas in a constant volume)ideal gas law (​the proportional relationship between the number of particles of a gas and the pressure in a constant volume)torquethe center of masscapillary action (wicking of water into the felt)wet-bulb temperature (temperature difference between head and body bulbs depends on the relative humidity of the air)the Maxwell-Boltzmann distributionheat of vaporization/heat of condensationfunctioning of a heat engine Safety The sealed drinking bird is perfectly safe, but the fluid inside the toy is not non-toxic. Older birds were filled with a flammable fluid. The dichloromethane in the modern version is not flammable, but if the bird breaks, it is best to avoid the liquid. Contact with dichloromethane can cause skin irritation. Inhalation or ingestion should be avoided because the chemical is a mutagen, teratogen and possibly a carcinogen. The vapor quickly evaporates and disperses, so the best way to deal with a broken toy is to ventilate the area and allow the fluid to disperse.