Two countries used different methods to produce their energy. Albania used fossil fuels, while Croatia used Nuclear fission. Which country used fewer radioactive elements? Hint: In the U.S., the majority of electricity is produced by burning coal or other fossil fuels. This causes air pollution, acid rain, and global warming. Fossil fuels are also limited and may eventually run out. Like fossil fuels, radioactive elements are limited. In fact, they are relatively rare, so they could run out sooner rather than later. On the other hand, nuclear fission does not release air pollution or cause the other environmental problems associated with burning fossil fuels. This is the major advantage of using nuclear fission as a source of energy.
Ans: Albania

Joe is at a party and carrying around a can of beer that he has had in his hand for awhile. He bumps into Sally, and they begin chatting. During their conversation, Sally notices the beer in Joe's hand, and remarks that a beer sounds like a good idea. She heads over to the refrigerator and grabs a nice cold one and pops it open. She takes a sip while the two continue their chat. The molecules in whose can of beer are moving faster? Hint: Liquid water is a fluid. The hydrogen bonds in liquid water constantly break and reform as the water molecules tumble past one another. As water cools, its molecular motion slows and the molecules move gradually closer to one another. The density of any liquid increases as its temperature decreases. For most liquids, this continues as the liquid freezes and the solid state is denser than the liquid state. However, water behaves differently. It actually reaches its highest density at about 4C.
Ans: Joe

Two researches studied the Earth's mantle. Clint studied mantle melting, and his pal Uri decided to study other mantle related phenomena. Which researcher read less about lowering the mantle's melting point? Hint: Mantle melting can come about three ways: (1) when the temperature rises, (2) if the pressure lowers (which lowers the melting point), and (3) if water is added, which lowers the melting point. Two of these (1 and 3) might explain why there are volcanoes at convergent plate boundaries: the temperature of the subducting plate increases as it sinks into the hot mantle (1). Sediments lying on top of the subducting plate contain water. As the sediments subduct, the water rises into the overlying mantle material. This lowers the melting temperature of the mantle (3). When the mantle above the subducting plate melts, volcanoes form above it. This leads to volcanoes in an island arc or continental arc.
Ans: Uri

Pam and Mary were two gardener friends. They both had some aphid infestations, but Mary had more aphids on her farm, so she used every method and insecticide available to get rid of them, with limited success. Which farmer sprayed plants thoroughly with a strong water jet? Hint: Insecticide control of aphids is difficult, as they breed rapidly, so even small areas missed may enable the population to recover promptly. Aphids may occupy the undersides of leaves where spray misses them, while systemic insecticides do not move satisfactorily into flower petals. Finally, some aphid species are resistant to common insecticide classes including carbamates, organophosphates, and pyrethroids.For small backyard infestations, spraying plants thoroughly with a strong water jet every few days may be sufficient protection. An insecticidal soap solution can be an effective household remedy to control aphids, but it only kills aphids on contact and has no residual effect. Soap spray may damage plants, especially at higher concentrations or at temperatures above 32 C (90 F); some plant species are sensitive to soap sprays.
Ans: Mary