Lab #1

Question 1

The Scientific Method

Answer 1

1. Observation of a phenomenon​
   
   • Subsequent development of questions.​
   2. Formulation of a hypothesis​
      - A supposition that explains an observed phenomenon, leading to testable predictions
   3. Testing through experimentation​
      Additional controlled observations.​
   4. Development of a conclusion​
      • Evaluation of hypothesis in light of experimental data.

Question 2

Controls

Answer 2

keep untested variables constant.​

Establishing a control​

Reinstall your old battery, check for tight cables, now try to start the car.​

If car still fails to start on old battery, the only variable in this investigation now is the effectiveness of the battery.

Question 3

microscope parts

Answer 3

https://imgur.com/gq1ESX4

Question 4

magnification levels

Answer 4

4x = scanning
10x = low power
40x = high power or high dry
100x = oil immersion

Question 5

ms part: ocular

Answer 5

the lens at the top of the microscope that you look through. They eyepiece is usually 10x or 15x power.

Question 6

ms part: Tube

Answer 6

connects the eyepiece to the objective lenses.

Question 7

ms part: Arm

Answer 7

supports the tube and connects it to the base of the microscope.

Question 8

ms part: Base

Answer 8

the bottom of the microscope, used for support.

Question 9

ms part: light

Answer 9

a steady light source (110v) used in place of a mirror. If your microscope has a mirror, it is used to reflect light from an external light source up through the bottom of the stage.

Question 10

ms part: stage

Answer 10

the flat platform where you place your slides. Stage clips hold the slides in place. If your microscope has a mechanical stage, you will be able to move the slide around by turning two knobs. One moves it left and right, the other moves it forward and back.

Question 11

ms part: revolving nosepiece

Answer 11

this is the part of the microscope that holds two or more objective lenses and can be rotated to easily change power (magnification).

Question 12

ms part: objective lenses

Answer 12

usually you will find 3 or 4 objective lenses on a microscope. They almost always consist of 4x, 10x, 40x and 100x powers. When coupled with a 10x (most common) eyepiece lens, we get total magnification of 40x (4x times 10x), 100x, 400x, and 1000x.

Question 13

ms part: condenser lens

Answer 13

the purpose of the condenser lens is to focus the light onto the specimen. Condenser lenses are most useful at the highest powers (400x and above). Microscopes with a stage condenser lens render a sharper image than those with no lens (at 400x). If your microscope has a maximum power of 400x, you will get the maximum benefit by using a condenser lenses rated at 0.65 NA or greater. 0.65 NA condenser lenses may be mounted in the stage and work quite well. A big advantage to a stage mounted lens is that there is one less focusing item to deal with. If you go to 1000x then you should have a focusable condenser lens with an N.A. of 1.25 or greater. Most 1000x microscopes use 1.25 Abbe condenser lens systems. The Abbe condenser lens can be moved up and down. It is set very close to the slide at 1000x and moved further away at the lower powers.

Question 14

ms part: diaphragm or iris

Answer 14

Many microscopes have a rotating disk under the stage. This diaphragm has different sized holes and is used to vary the intensity and size of the cone of light that is projected upward into the slide. There is no set rule regarding which setting to use for a particular power. Rather, the setting is a function of the transparency of the specimen, the degree of contrast you desire and the particular objective lens in use.

Question 15

Parfocal microscope

Answer 15

objectives stay in focus when magnification is changed; i.e., if the microscope is switched from a higher power objective (e.g., 40×) to a lower power objective (e.g., 10×), the object stays in focus.

Question 16

relationship between light and magnification

Answer 16

As magnification increases, the working distance decreases (there is less space between the lens and the slide). As magnification increases, light intensity decreases. This means that the 10x objective is brighter than the 40x objective.