1. 1  Sometimes, gimbal. a contrivance, consisting of a ring or base on an axis, that permits an object, as a ship's compass, mounted in or on it to tilt freely in any direction, in effect suspending the object so that it will remain horizontal even when its support is tipped.
Phage typing is a method used for detecting single strains of bacteria. It is used to trace the source of outbreaks of infections. The viruses that infect bacteria are called bacteriophages (phages for short) and some of these can only infect a single strain of bacteria. These phages are used to identify different strains of bacteria within a single species. A culture of the strain is grown in the agar and dried. A grid is drawn on the base of the petri dish to mark out different regions. Inoculation of each square of the grid is done by a different phage.
Measuring pH can be done simply and quickly using pH test paper, pH indicator sticks, or a pH meter. pH test paper and indicator sticks are pieces of paper or stiffer sticks that contain pH indicators (chemicals that change color depending on how acidic or basic a solution is). To measure pH, a piece of pH test paper or an indicator stick is dipped into the liquid. The color of the dipped paper/stick is then matched to a color key that comes with the container of pH test paper or indicator sticks. Each color on the key represents a different pH. An example of a used pH indicator stick and the corresponding color key is shown below in Figure 1. pH meters are electronic devices that used to measure pH. They consist of a probe that is dipped in a solution, and a digital readout. pH meters are even more precise than pH test paper or indicator sticks.