Shape
Beakers are often graduated, that is, marked on the side with lines indicating the volume contained. For instance, a 250 mL beaker might be marked with lines to indicate 50, 100, 150, 200, and 250 mL of volume. These marks are not intended for obtaining a precise measurement of volume (a graduated cylinder or a volumetric flask would be a more appropriate instrument for such a task), but rather an estimation.
The presence of a lip means that the beaker cannot have a lid. However, when in use, beakers may be covered by a watch glass to prevent contamination or loss of the contents, but allowing venting via the spout. Alternatively, a beaker may be covered with another larger beaker that has been inverted, though a watch glass is preferable.
Read more about this topic: Beaker (glassware)
Famous quotes containing the word shape:
“somewhere in sands of the desert
A shape with lion body and the head of a man,
A gaze blank and pitiless as the sun,
Is moving its slow thighs, while all about it
Reel shadows of the indignant desert birds.”
—William Butler Yeats (1865–1939)
“What man dare, I dare.
Approach thou like the rugged Russian bear,
The armed rhinoceros, or the Hyrcan tiger;
Take any shape but that, and my firm nerves
Shall never tremble. Or be alive again
And dare me to the desert with thy sword.”
—William Shakespeare (1564–1616)
“This whole day have I followed in the rocks,
And you have changed and flowed from shape to shape,
First as a raven on whose ancient wings
Scarcely a feather lingered, then you seemed
A weasel moving on from stone to stone....”
—William Butler Yeats (1865–1939)