What is the working distance for a 4x objective lens?
Table 1 – Objective Specifications by Magnification
| Achromat Correction | ||
|---|---|---|
| Magnification | Numerical Aperture | Working Distance (mm) |
| 4x | 0.10 | 30.00 |
| 10x | 0.25 | 6.10 |
| 20x | 0.40 | 2.10 |
What is the working distance of a lens?
The working distance defines the free space between the object and the leading edge of the lens. Standard lenses are generally designed to focus objects ranging from infinity to a minimum object distance (MOD) in front of the lens. If the distance between lens and camera sensor is increased, the MOD can be reduced.
What happens if you use oil immersion lens without oil?
Without oil, light waves reflect off the slide specimen through the glass cover slip, through the air, and into the microscope lens (see the colored figure to the right). Unless a wave comes out at a 90-degree angle, it twists when it hits a new substance, the amount of twist depending on the angle.
Can broth tubes be used to observe motility?
Motility in living cultures can be observed by the Hanging Drop Technique. Use a loopful of an isolate either from a broth culture or from a tube of water into which a small amount of growth on solid medium has been transferred. A hanging drop slide is a quick way to examine motility.
What is the value of a hanging drop preparation?
What is the value of a hanging-drop preparation? Hanging drop preparation allows for the observation of living organisms; it is a more complex method than wet mount that allow for longer term observation of living organisms and more reliable observation of motility.
How do you observe bacterial motility?
Method
- Touch a straight needle to a colony of a young (18- to 24-hour) culture growing on agar medium.
- Stab once to a depth of only 1/3 to ½ inch in the middle of the tube.
- Incubate at 35°-37°C and examine daily for up to 7 days.
- Observe for a diffuse zone of growth flaring out from the line of inoculation.
What methods can be used to determine motility?
- Techniques to examine Motility.
- Soft Agar Deep Test for motility.
- Hanging Drop and motility.
- Flagella stain.
What reagents do you need for the motility test?
Small amounts of agar and gelatin are added to provide a semi-solid medium which allows macroscopic examination of bacterial motility. Organisms are stabbed into the medium which is then incubated for a 24 hour period. Motile organisms extend from the stab line and produce turbidity or cloudiness throughout the medium.
What is the magnification using observe bacterial motility?
A final magnification of 100x, should be sufficient with which to observe motility. For cell structures such as spores, parasporal crystals, etc., you will want to go to 400x. To view at 400x, move the condenser turret to the “DF” position and rotate the 40x objective into place. Focus and center.