Plasma is one of the four fundamental states of matter (the others being solid, liquid, and gas). Heating a gas may ionize its molecules or atoms (reducing or increasing the number of electrons in them), thus turning it into a plasma, which contains charged particles: positive ions and negative electrons or ions.

A rule change was enacted before the 1974 National Football League (NFL) season to add one sudden death overtime period (15 minutes) to all preseason and regular season games. If no team scored in this period, the game would result in a tie. This rule was enacted to decrease the number of tie games. The first ever regular season overtime, a September 22 game between the Pittsburgh Steelers and the Denver Broncos, ended in a 35-35 draw. It was not until November 10, when the New York Jets defeated the New York Giants, 26-20, that an overtime game would produce a winner.

Water polo, or water ball, is a team water sport. The playing team consists of six field players and one goalkeeper. The winner of the game is the team that scores the most goals. Game play involves swimming, treading water (using a sort of kicking motion known as "eggbeater kick"), players passing the ball while being defended by opponents, and scoring by throwing the ball into a net defended by a goalie. "Man-up" (or "power play") situations occur frequently. Water polo, therefore, has strong similarities to the land-based game of team handball.

The Doppler effect (or Doppler shift), named after the Austrian physicist Christian Doppler, who proposed it in 1842 in Prague, is the change in frequency of a wave (or other periodic event) for an observer moving relative to its source. It is commonly heard when a vehicle sounding a siren or horn approaches, passes, and recedes from an observer. The received frequency is higher (compared to the emitted frequency) during the approach, it is identical at the instant of passing by, and it is lower during the recession.

The Urnero (Leptodactylus latinasus) is a species of frog in the Leptodactylidae family. It is found in Argentina, Bolivia, Brazil, Paraguay, and Uruguay. Its natural habitats are subtropical or tropical moist shrub land, subtropical or tropical dry lowland grassland, subtropical or tropical seasonally wet or flooded lowland grassland, freshwater marshes, intermittent freshwater marshes, pastureland, rural gardens, and ponds.