United States or Czechia ? Vote for the TOP Country of the Week !
Similarly, a burette used for the titration of the 50 cc. of solution removed should be calibrated under the same conditions as the measuring flasks or pipettes employed with it. The student should also keep constantly in mind the fact that all volumetric operations, to be exact, should be carried out as nearly at a constant temperature as is practicable.
Wide-mouthed jars, empty or holding dirty water, stood on other tables ranged up and down the middle of the room, and there was a litter of porcelain-lined trays, test tubes, pipettes, glass stirring-rods and racks for microscope slides.
They took small, sealed packets of dehydrated food in through their chest airlocks, unsleeved their arms, emptied the packets into plastic squeeze bottles from the utensil racks before them, injected water from the pipettes which led to their shoulder tanks, closed the bottles and let the powdered gruel swell as it reabsorbed moisture. The gruel turned out hot all by itself.
Then he opened a drawer and from a number of capillary pipettes selected a plain capillary tube of glass. He held it in the flame of a burner until it was red hot. Then carefully he drew out one end of the tube until it was hair fine. Again he heated the other end, but this time he let the end alone, except that he allowed it to bend by gravity, then cool. It now had a siphon curve.
Again he peeked through the glowing bull's-eye. Then, his face slightly pale, his bulging eyes blinking nervously, he took two small flint glass bottles, set them under a couple of pipettes, and deftly made connections.
It is plain that any temperature which is deemed most convenient might be chosen for a particular laboratory, but it cannot be too strongly emphasized that all measuring instruments, including burettes, pipettes, and flasks, should be calibrated at that temperature in order that the contents of each burette, pipette, etc., shall be comparable with that of every other instrument, thus permitting general interchange and substitution.
While Nadia controlled her impatience as best she could, Stevens manipulated the bulbs and pipettes of the gas apparatus. "Pressure, fifty-two centimeters more than I dared hope for and analysis all x, I believe. Oxygen concentration a little high, but not much." "We won't have to wear the space-suits, then?" "Not unless I missed something in the analysis.
Balloons, tubes, pipettes, pneumatic vats, receivers, cupels, lamps, bell-glasses, blow-pipes, and mortars, he passed in review to assure himself that during his absence nothing had been damaged. He carefully dusted his jars, examined the labels, made sure that none of his treasures were cracked, that his gauges were not out of order.
There, grouped picturesquely round a quantity of large tanks, stood the Wenuses, blowing assiduously through pellucid pipettes and simultaneously chanting in tones of unearthly gravity a strain poignantly suggestive of baffled hopes, thwarted aspirations and impending departure. So absorbed were they in their strange preparations, that they were entirely unconscious of my presence.
Pipettes are usually already graduated when purchased, but they require calibration for accurate work. PROCEDURE. Clean the pipette. Draw distilled water into it by sucking at the upper end until the water is well above the graduation mark. Quickly place the forefinger over the top of the tube, thus preventing the entrance of air and holding the water in the pipette.
Word Of The Day