Download Grade 7 Science(The Microscope) and more Exercises Environmental science in PDF only on Docsity!
Hi! Have a great day! Welcome to the nature of Biology, where you will learn the
diversity of life. Do you know that living things of unique classes, big or small consist of
cells? Yes, some organisms are single- celled while others are made up of billions of cells
like our body or have trillions like the elephants.
Most cells are so small that they cannot be seen by our naked eye. But, how can
we examine these cells? We are grateful and lucky enough that our scientists and
inventors in their times built the microscope, a special equipment or tool to make small
objects like cells look bigger. In this module, you will learn the brief history and types
of microscope. You will also study the parts of the microscope and how does each part
function. Knowing this lesson is very essential in your future use especially in viewing
different internal structures of living things under the microscope.
The module is divided into two lessons, specifically:
- Activity 1: Brief History of Microscope
- Activity 2: Parts and Functions of a Microscope
After going through this module, you are expected to:
- Define Microscope;
- state the function of a microscope;
- identify the various type of microscope;
- label the parts of the microscope; and
- describe the functions of each part of the microscope.
Directions: Read each item carefully. Write only the letter of the correct answer for
each question. Write your answer on your activity notebook.
- What tool is used to help you see tiny objects and living organisms?
A. Goggles B. Microscope C. Stethoscope D. Telescope
- Who invented the first compound microscope? A. Isaac Newton B. Robert Hooke C. Alexander Graham Bell D. Hans & Zacharias Janssen
What I Need to Know
What I Know
- Which two parts of the light microscope magnify the image of an object?
A. Eyepiece & mirror B. Eyepiece & objective C. Objectives & mirror D. Objectives & diaphragm
For items 4 to 6, use the letters in the figure to answer the questions.
- What part moves the body tube and objectives up and down?
A. Part A B. Part B C. Part H D. Part I
- Which part makes possible the changing of the objectives?
A. Part I B. Part J C. Part L D. Part H
- Which part will you adjust if the onion cell you are observing under HPO is not
clear? A. Part B B. Part C C. Part G D. Part J
- What makes a microscope determine how clearly a small object can be viewed?
A. Mirror & eyepiece B. Mirror & magnification C. Magnification & resolution D. eyepiece & resolution
J
L
- A plant cell is viewed using a 10x eyepiece and 43x HPO. How much will the cell be
magnified?
A. 10x B. 43x C. 143x D. 430x
- How does a mirror help in studying the specimen in a microscope?
A. It cleans the cover slip. B. It cleans the glass slide. C. It gives light directly to the eyes of the user. D. It reflects light to illuminate the specimen.
- Why is it necessary for the specimen to be observed under the microscope must be
thin?
A. So that the image will be clearer. B. So that the image would be larger. C. So that light could pass through the specimen. D. So that the high magnification objective can be used.
Hello students. In the previous grades, you learned that the basic unit of
structure and function of all living things is the cell. Living things may have trillions of
cells and are called multicellular organisms or may contain one cell and ARE called unicellular organisms.
We cannot see the cells using the naked eye because they are too tiny. Have you
imagined how the structure of the cells appear when they were discovered? It’s even
more difficult to identify the smaller cell organelles inside. What other tools can we use
to make things appear bigger? Can you name some of them? How are they used? Write
your answer in a separate sheet of paper.
TOOL/S USE/S
What’s In
Hand lens/
magnifying glass
Used to produce a magnified image
of an object.
Periscope
Used for looking over the surface
of the sea from submarine.
Telescope
Used to look through distant
objects look closer and larger.
Binoculars Used to look through to see distant
objects more clearly.
Opera glasses
Used to look through so that the actors on a stage can be seen more clearly.
As we go along with our lesson, activities will be more exciting and thrilling. Are
you ready? Let’s get started.
It is fascinating to know the process by which many designers and inventors
conceptualize an innovation. Through this activity, you will discover the different
scientists who contributed to the invention of microscope.
ACTIVITY 1: MATCHY! MATCHY!
What to Do:
- Read the paragraphs below.
- Trace the history of the microscope by copying and filling in the boxes.
- The first item is done for you.
- Write your answer in your paper.
On the early 13th^ century, spectacle makers were producing lenses for glasses. The early simple “microscopes” were known as “flea glasses” because they were used to study small insects. A father- son duo, Zacharias and Hans Janssen, created the first microscope in the 1590s. In the year 1625, Galileo Galilei perfects the principle of microscope. In 1665, an English physicist, Robert Hooke looked at a sliver of cork through a microscope lens and notice some “pores” or “cells” in it. Anton van Leeuwenhoek built a simple microscope in 1674 with only one lens to examine blood, yeast, insects and many other tiny objects. In year 1925, Richard Zsigmondy developed the ultra-microscope that could study objects below the wavelength of light and won a Nobel Prize in Chemistry in 1925. The phase- contrast microscope was invented by Frits Zernike in 1932, allows the study of colorless and transparent biological materials. Little was done to improve the microscope until the middle of the 19 th^ century when great strides were made and quality instruments like today’s microscope emerged.
What’s New
Hans and Zacharias Janssen produced the first compound microscope in the
1590s. They were Dutch eyeglass makers. They began experimenting with ways to use
different lenses. When they put a lens at the end of a small tube, they discovered that
the objects near the end were magnified more than the lens by itself could achieve.
Galileo Galilei was credited with inventing one of the first compound microscope
in the year 1625. It is called compound microscope because it has more than one lens.
He added a focusing device to his microscope and of course went on to explore the
heavens with his telescopes.
In 1665, Robert Hooke had access to many microscopes available in Royal Society
of London. He examined everything he could get his hands on. When he examined a
very thin slice of cork, he thought the close- up views resembled small, empty rooms. It
reminded him of small rooms found in monastery; thus he named these rooms’ cells.
This gives way to the discovery of cell.
In 1674, Anton van Leeuwenhoek, Dutch scientist, worked to create stronger
lenses that result to more powerful microscope. He was one of the first scientists able
to observe bacteria movement in a single drop of pond water.
The prototype for the compound microscope was credited to Joseph Jackson Lister
in 1830, which reduces spherical aberration or the “chromatic effect” by showing that
several weak lenses used together at certain distances gave good magnification without
blurring the image.
Ernst Abbe, research director of the Zeiss Optical Works, wrote a mathematical
formula called the “Abbe Sine Condition”. His formula provided calculations that allowed
for the maximum resolution in microscopes possible in 1872.
In 1903, Richard Zsigmondy developed the ultra- microscope that could study
objects below the wavelength of light and he won the Nobel Prize for Chemistry in 1925.
Frits Zernike invented the phase- contrast microscope in 1932 that allowed for the
study of colorless and transparent biological materials for which he won the Nobel Prize
in Physics in 1953.
In 19th^ century, companies in Germany like Zeiss and an American company
founded by Charles Spencer began producing fine optical microscope.
What is It
Are you getting familiar with the inventors and their contribution to the
development of the microscope? Let us have another activity focusing on the timeline of
the development of the microscope.
Make a brief timeline about the development of the microscope. You will call it
“TIMEZONE TRAVEL FROM THE PAST TO THE PRESENT”. The first one is done for
you to serve as guide.
Today 1950
Now that you’ve learned about the history of the development of the microscope,
let us find out how far you have understand by answering the activity below. Are you
ready? Let’s start.
Directions : Describe the following scientists below and tell something about their
contribution to the development of the microscope. Write your answer on your activity notebook.
SCIENTISTS CONTRIBUTIONS
- Robert Hooke
- Hans & Zacharias Janssen
- Anton van Leeuwenhoek
- Richard Zsigmondy
What’s More
1590 Father- and- son duo, Zacahrias & Hans Janssen, invented the first compound microscope.
What I Have Learned
Coined the term cell. Produced the first compound microscope. Described a living cell from a single drop of water. Developed the ultra-microscope that could study objects below wavelength of light.
1625 Galileo Galilei was credited with inventing one of the first compound microscope
1665 Robert Hooke coined the term 'cells'.
1674 Anton van Leeuwenhoek, first scientists able to observe bacteria movement in a single drop of pond water.
1830 prototype for the compound microscope was credited to Joseph Jackson Lister. (^) Ernst Abbe^1872 wrote a mathematical formula called the “Abbe Sine Condition”. It provided calculations that allowed for the maximum resolution in microscopes possible. 1903 Richard Zsigmondy developed the ultra- microscope that could study objects below the wavelength of light.
1932 Frits Zernike invented the phase- contrast microscope that allowed for the study of colorless and transparent 19th century biological materials Companies in Germany like Zeiss and an American company founded by Charles Spencer began producing fine optical microscope.
What is a microscope? What are functions of the different parts of a microscope?
What are the types of microscopes?
A microscope comes from the Ancient Greek micros meaning “small” and
skopein , which means “to look”, is a tool which can help you see tiny objects and living
organism. It makes them look bigger. The science of investigating small objects and
structures using such an instrument is called microscopy.
What makes a microscope determine how clearly a small object can be viewed?
- Magnification- describes how much larger an object appears when viewed
The magnification is written on the side of the lens. The value could be 4x, 10x,
40x or 100x. To calculate the total magnification of the compound light microscope,
multiply the magnification power of the ocular lens by the power of the objective lens.
For example, a 10x ocular lens and a 40x objective would have a 400x total
magnification.
2. Resolution or resolving power- the capacity of a microscope to distinguish finer details of an image.
What is It
Revolving Nosepiece
Objective Lens
Coarse Adjustment
Fine Adjustments
Body Tube
Stage
Diaphragm
There are different types of microscopes which differ in their magnification and
their resolving power, namely,
1. Optical microscope- uses visible light to form an image. It uses glass lenses to magnify
and resolve images. The image that was formed can be viewed from an eyepiece. It has
two types:
A. Compound- uses two or more double convex lenses to magnify the object; it can magnify object up to 1200x
B. Stereomicroscope- also known as dissecting microscope; it magnifies the object 100x and gives three- dimensional image
2. Electron microscope- uses high energy electron beams to form an image. The image
that was formed can only be viewed from a photographic plate or from a computer screen; the image magnified can reach up to 2 000 000x.
A. Transmission electron microscope (TEM)- electron beam passes through an ultra- thin sample; the image magnified and focused onto an imaging device such as fluorescent screen, to be examined in fine detail
B. Scanning electron microscope (SEM)- electron beam bounces off from the surface of the sample; thus, the image provided is three- dimensional
Parts and Function of a Microscope
- Eyepiece or Ocular lens , this is the part used to look through the microscope.
- Body tube or Lens tube is connected with the eyepiece and its main task is to hold it.
- Revolving nosepiece , it holds the objective lenses. It is movable and it can revolve
the objective lenses depending on the magnification power of the lens.
- Arm , this is the part connecting the base and to the head and the eyepiece tube to
the base of the microscope. It gives support to the head of the microscope and it is also
used when carrying the microscope.
- Objectives/ objective lenses , are the major lenses used for specimen visualization.
Most schools have light microscope with three objectives and others have four. Usually,
the shortest one marked 3x, 4x or 5x is called scanner. The lower power objective
(LPO) is marked 10x or 12x, while the high power objective (HPO) is marked 40x, 43x
or 60x. The objectives magnify the object to be observed to a certain size as indicated by
the 3x, 10x or 40x, etc. marks.
- Stage is the platform that holds the specimen or sample for viewing.
- Stage clips hold the specimen slides in place.
ACROSS
2 - a tool which can help you see tiny objects and living organism
4 - it supports the microscope
5 - controls the amount of light that passes through the specimen
7 - provides a space where the slide can be examined
9 - provides light for the specimen
10 - magnify the specimens
DOWN
1 - focuses images under the high- power and oil- immersion objectives
3 - holds the slide in place
6 - used to carry the microscope
8 - part where the viewer views the sample
Good job! It truly shows how much you enjoyed and learned our lesson. Are you
ready to have some more? Let’s start the ball rolling.
Directions : Match the function of the microscope in Column A with its part in Column
B. Write the letter of your answer in your activity notebook.
COLUMN A COLUMN B
- It holds the slide in place. A. fine adjustment
- It holds the objectives. B. stage clips
- Provides light for the specimen. C. revolving nosepiece
- This focuses the images under the D. light source
HPO and oil immersion objectives. E. arm
- This part allows you to carry F. coarse adjustment
the microscope. G. base
- This supports the microscope. H. diaphragm
- Focuses the images under the I. ocular lens
scanner and the LPO. J. body tube
- It provides a space where the K. stage
slide can be examined. L. rack stop
- It is connected with the eyepiece.
10.This is the part used to look
through the microscope.
What I Have Learned
Congratulations! You’re fantastic and really enjoyed your exploration in the world
of microscopy. Here is your final challenge to prove what you got. Write your answer in
your activity notebook.
In this time of CoVID19 Pandemic, how useful is the microscope in detecting the viruses? What kind of microscope is being used in studying this kind of virus? Here are your criteria to follow in answering this task in order for you to be
guided and lead to an appropriate answer.
FEATURES 4 3 2 1
Quality of Writing
- Piece was written in an extraordinary style
- Very informative and well organized - Piece was written in an interesting style - Somewhat informative and organized - Piece had little style - Gives some new information but poorly organized - Piece had
no style
new
information
and very
poorly
organized
Grammar, Usage & Mechanics
- No incorrect spelling, punctuation or grammatical errors
- Few spelling and punctuations, errors, minor grammatical errors
- A number of spelling, punctuation or grammatical errors
- So many spelling, punctuation and grammatical errors that it interferes with the meaning
What I Can Do
- Edgar needs to raise the stage to focus the specimen he is studying using the low
power objective. Which part should he manipulate? A. Part A B. Part B C. Part C D. Part E
- You are to transfer the microscope to the next room. What parts should you hold to
carry the microscope properly? A. Part C & E B. Part B & C C. Part A & F D. Part E & J
- Which part will you adjust if the object you are observing under the HPO is NOT
clear? A. Coarse adjustment B. Inclination joint C. fine adjustment D. Diaphragm
- Which of the following describes the function of the mirror?
A. It facilitates the changing of the objectives. B. It reflects light up to the diaphragm and to the specimen to be observed. C. It allows one to tilt the microscope, so viewing is possible while seated.
D. Regulates the amount of light reflected to the object to be viewed.
- Which of the following describes the function of diaphragm?
A. It facilitates the changing of the objectives. B. It reflects light up to the diaphragm and the specimen to be observed.
C. Regulates the amount of light reflected to the object to be viewed.
D. It allows one to tilt the microscope, so viewing is possible while seated.
- What is the correct way of carrying a microscope?
A. Hold the arm by grasping with one hand. B. Hold the base by grasping with two hands. C. Hold the arm by grasping with one hand and the stage with the other hand. D. Hold the arm by grasping with one hand and the base with the other hand.
- Total magnification is obtained by ______________.
A. magnifying power of eyepiece. B. magnifying power of condenser lens. C. magnifying power of the objective lens. D. magnifying power of both the objective lens and eyepiece.
- Which should be used to observe bacteria?
A. 2 0x obj. and 1 0 x eyepiece B. 3 0 x obj. and 10x eyepiece C. 100 x oil immersion objective and 10 x eyepiece D. 10 0x oil immersion objective and 5 x eyepiece
- Why does a microscope stage have a hole in it?
A. To hold the specimen in place. B. To make the specimen visible. C. To secure the slide to the stage. D. To allow the light to pass through.
- A student wants to see the parts of a plant cell in detail using high power objective.
What part of the microscope will be manipulated?
A. Eyepiece B. Objective lenses C. Fine adjustment knob D. Coarse adjustment knob
- It is the ability of a microscope to distinguish the finer details in an image.
A. microscopy B. scanning ability C. magnification D. Resolving power
References
Books
Alvie J. Asuncion et.al. K to 12 Science Grade & Leraners Material. Pasig City: Bureau
of Learning Resources (DepEd- BLR), 2017.
Laurente, Jomar Aries T., Ryan John G. Garcia, Faith Celeste B. Ole, Von Anthony G. Torio, and Arnie C. Osabel. Science for the 21st Century Learner 7. 2015.
Websites
biologyonline.com. n.d. https://www.biologyonline.com (accessed June 5, 2020).
Google.com. n.d. https://sites.google.com/a/amschool.org/7th-grade-math/grade-
2/march23-26 (accessed June 1, 2020).
micro.magnet. n.d. https://micro.magnet.fsu.edu/primer.primergal.html (accessed
June 2, 2020).
MicroscopeWorld. n.d. www.MicroscopeWorld.com (accessed June 2, 2020).
Peñol, Joevanie S. slideshare.net. n.d.
https://www.slideshare.net/mobile/joevani_007-parts-and-functions (accessed June 6, 2020).
Pinterest.ph. n.d. https://www.pinterest.ph/pin/93449761002851047/ (accessed
June 1, 2020).
sciencing.com. n.d. https://sciencing.com (accessed June 5, 2020).
tes.com. n.d. https://www.tes.com/teaching-resource/history-of-microscopes-
comprehension-task-6377321 (accessed June 5, 2020).
Viau, Francois. teach-nology.com. n.d. https://www/teach-nology.com (accessed June
6, 2020).
For inquiries or feedback, please write or call:
Department of Education - Bureau of Learning Resources (DepEd-BLR)
Ground Floor, Bonifacio Bldg., DepEd Complex
Meralco Avenue, Pasig City, Philippines 1600
Telefax: (632) 8634-1072; 8634-1054; 8631- 4985
Email Address: [email protected] * [email protected]
