Class N° 3

Hello! It’s good to contact you again. In this opportunity we are practising the Simple Present Tense. And the topic of this class is THE MISCROCOPE, something you use every day in your profession.

Reading Activity: “THE MICROSCOPE”:

                The development of the microscope has greatly affected human life. Before it was invented, scientists knew very Little about those objects too small to be seen by the human eye, such as tiny creatures, bacteria, and viruses.

                Today, the microscope is used in many activities. Modern microbiologists use the microscope to study cell structures and the cell processes that are responsable for life itself. Specialised low-power microscopes are used in the assembly of small electronic circuts and for detailed surgical operations. As industrial tool, the microscope assists in detection of food spoilage, medicine adulteration, and minute structural defects in metals.

                There are different types of microscopes. The simple and compound ones are called optical microscopes. That is, they use a beam of light and lenses to magnify objects. Another type is the monocular microscope. It is used fro viewing with one eye. Magnification depends on the objective lens and the eyepiece. There are usually three objectives in a monocular microscope, typically with magnifications of 10, 40, and 100. These magnifications change by rotating the objectives, which are fitted into a disk, called the nosepiece.

                If you want to study coloidal particles, which are larger tan atoms, you will need and ultramicroscope because you cannot see them with an ordinary optical microscope. Finally, we can mention the electrons instead of light through a specimen that finally goes to the image-recording system. Thanks to the devices, researchers have made the most incredible discoveries in science. And there are still more to come…!

Comprehension activities:

a)      Re-read the text and complete the sentences with your own words:

·         We use specialised low-power microscope to……………………………………………

……………………………………………………………………………………………

·         Optical microscopes are used to……………………………………………………………

……………………………………………………………………………………………

·         The monocular microscope………………………………………………………………

……………………………………………………………………………………………

·         To study coloidal particles………………………………………………………………

……………………………………………………………………………………………

·         The electron microscope is used …………………………………………………………

……………………………………………………………………………………………

b)      Choose the correct option:

·         Thanks to the microscope, we can see………..

BACTERIA                 VIRUSES             BOTH

·         Magnifications change by…………

MAKING THE OBJECTS ROTATE      

  ROTATING THE OBJECTIVES AND THE DISK           CREATING A ROTATION IN NOSEPIECE

·         Nowadays, microscopes have many uses such as……….

DETECTION OF DEFECTS IN MEDICINES                CELL STRUCTURE AND PROCESS STUDY

                                       DEFECTS IN MINERALS

·         Optical microscopes are……………..

PREPARED TO SEE WITH ONE EYE         DIVIDED INTO COMPOUND AND SIMPLE

                                     USED TO MAGNIFY OBJECTS WITH A LENS

·         Ultramicroscopes ……….

ARE USED TO STUDY ATOMS           CANNOT SEE AS ORDINARY MISCROSCOPES

                                  ARE ABLE TO STUDY COLLOIDAL ON PARTICLES

·         The electron microscope……….

SENDS A BEAM OF LIGHT THROUGH THE SPECIMEN 

 WORKS WITH ELECTRON BEAMS

DIRECTS A BEAM OF ELECTRIC LIGHT

C) Simple Present tense: write the correct form of the verbs in brackets:

1- Scientis ………………………..(see) viruses and bacteria through microscopes.

2- Doctors………………….(not-perform) very detailed surgical operations without a microscope.

3- ………………….a microbiologist …………………………..(detect) food spoilage without a microscope?   No, ………………….    ……………………………

4- A microbiologist……………………(study) cell structures and processes with the microscope.

5- A monocular microscope……………..(have) three types of magnifications.

6- The low-power microscope…………………….(be) used for industrial purposes.

7- Magnifications………………………..(change) according to the size of the objectives.

8- ……………….researchers…………………….(use) microscopes in their investigations?

     Yes, ……………….   ………………….

9- A scientist ……………………….(not-analyse) coloidal particles without the ultramicroscope.

10- Microscopes …………..(be) very useful devises.