A world under the microscope

It is not easy to observe nature in order to understand it. We have to be very patient, curious and at the same time be educated and possess a corresponding knowledge in different spheres of life. To explore the nature around us we are going to use magnifiers and microscopes. The advantages are obvious - we can discover the unusual world of common things and a have a closer look at nature. We expect to unveil something new which is impossible to do without microscopes and magnifying glasses.

First of all let´s have a look at the gadgets we are going to use.

Magnifying glasses

A magnifying glass is a convex lens that lets the observer see a larger image of the object being observed.

The magnification of a magnifying glass depends upon where it is placed between the user's eye and the object being viewed and upon the total distance between eye and object.

The magnifying power is the ratio of the sizes of the images formed on the user's retina and the lens.

The highest magnifying power is obtained by putting the lens very close to the eye and moving both the eye and the lens together to obtain the best focus.

Picture 1

Microscopes

A microscope (from the Ancient Greek: "small" and "to look" or "see") is an instrument used to see objects that are too small to be seen by the naked eye. Microscopy is the science of investigating small objects and structures using such an instrument. Microscopic means invisible to the eye unless aided by a microscope.

Picture 2

To use a microscope is a bit harder.

Here are some main steps you should follow to operate a microscope in the correct way:

1. Place the microscope slide on the stage and fasten it with the stage clips.2. Look at the objective lens (and the stage from the side and turn the focus

knob so the stage moves upward. Move it up as far as it will go without letting the objective touch the coverslip.

3. Look through the eyepiece and move the focus knob until the image comes into focus.

4. Adjust the condenser and light intensity for the greatest amount of light.5. Move the microscope slide around until the sample is in the centre of the

field of view (what you see).6. Use the focus knob to place the sample into focus and readjust the

condenser and light intensity for the clearest image.7. Do not let the objective lens touch the slide!8. When finished, lower the stage, click the low power lens into position and

remove the slide.

Now when we are acquainted with microscope and magnifying glass we can start our exploration. To begin with we have chosen some flowers in blossom. Blossoms come in such a bewildering variety of shapes, sizes, and basic structures that to keep from getting befuddled it helps to have some kind of "anchor." Our anchor is the "Standard Blossom," the flower drawn below.

Picture 3

Now let´s have a look at the bloom under the magnifying glass:

picture 4

Here the list of the main parts of the bloom and their descriptions:

Peduncle: The stalk of a flower.

Receptacle: The part of a flower stalk where the parts of the flower are attached.

Sepal: The outer parts of the flower (often green and leaf-like) that enclose a developing bud.

Petal: The parts of a flower that are often conspicuously colored.

Stamen: The pollen producing part of a flower, usually with a slender filament supporting the anther.

Anther: The part of the stamen where pollen is produced.

Pistil: The ovule producing part of a flower. The ovary often supports a long style, topped by a stigma. The mature ovary is a fruit, and the mature ovule is a seed.

Stigma: The part of the pistil where pollen germinates.

Ovary: The enlarged basal portion of the pistil where ovules are produced.

Assignments:

1. Look at picture 4 and label the parts of the bloom

2. Find the Czech equivalents for the following words:

reduncle -

receptacle -

sepal -

petal -

stamen -

anthern -

pistil -

stigma -

ovary -

3. Match these parts of a flower with their description:

a) Petal, b) Bract, c) Receptacle, d) Stigma.

__ The generally enlarged top of the footstalk, which supports the other parts of the flower. Some "fruits" are enlarged receptacles rather than ovaries.

__ A leaf-like element below a flower or on an inflorescence. Bracts are typically shaped differently than other leaves on the plant. They are usually green, but occasionally are brightly colored and petal-like.

__ The upper part of the pistil which receives the pollen. The stigma is often sticky, or covered with fine hairs or grooves, or other anatomical features that help the pollen to adhere. It may be cleft into several parts.

__ A division or lobe of the corolla or inner perianth of a flower.

4. Make a sketch of a male and female bloom

Complete the criss-cross puzzle with the following words:

Across Down2. stonek 1. nástroj4. neviditelný 3. pozorovat6. čočka 5. květ7. zkoumat 8. okvětní lístek10. samčí 9. plod12. lupa 11. list15. pyl 13. samičí16. květ (stromu) 14. semeno

17. tyčinka