1. LookThinkDiscussAgreeShareWrite What do these things have in common ? They all make things look bigger!

2. Learning Intention MICROSCOPES Learning objectives All (must) Understand that microscopes are used to magnify things; be able to use a microscope to view slides. Most (Should) Name the basic parts of a microscope; Calculate microscope magnification; Explain how to prepare a slide; appreciate that stains can make things on a slide stand out. Some (could) describe what happens when a biopsy is taken; estimate the sizes of specimens under a microscope. Saturday, 04 June 2016

3. What do you see?

4. …If you look really carefully …If you look really carefully … Magnification: The power of magnifying The amount of increase in apparent size

5. Why is scale important?

6. Eye Piece Arm Stage Coarse Focus Fine Focus Base Tube Objective lens Stage Clamps Light Diaphragm

7. The microscope The objective lens is the lens nearest the object. The magnifiaction of the microscope can be changed by rotating a different objective lens into place. Magnfication is often x10 or x40. The stage is where the slide with the object is placed. It contains clips that hold the slide. The iris or diaphragm controls how much light goes through the object.

8. Eyepiece Objective lens Mirror Base Stage clip Body Focussing Knob How to use a Microscope As you already know, Micro-Organisms are very small, too small to be seen with the naked eye. In order to be able to see and study Micro-Organisms, Micro-Biologists use a tool called a Microscope that allows us to see very small things. Before you attempt to use the Microscopes, look at the diagram below and make sure you can locate all the parts on your own Microscope. Now follow the instructions below Carefully. Make sure you have selected the low power objective lens (it’s the smallest). Look down the eyepiece and adjust the mirror until it is as light as you can get it. Move the focussing knob until the objective lens is as far down as it will go. Put your slide on the stage and secure it with the stage clips. Using the focussing knob, move the objective lens slowly up. Until you can see something. (You will need to keep looking down the eyepiece as you do this). When you think you can see something, check with the teacher before drawing what you see. When you have finished, remember to remove the slide from the microscope before packing it away.

9. How to work out the magnification Total magnification = magnification of eye piece lens x magnification of objective lens

11. 1 Label the parts using words from the box below. A B D E F C G ABCDABCD EFGEFG mirrorobjective lensslidestage coarse focusing wheel eyepiece lens fine focusing wheel Cross out the incorrect words in the brackets to complete the sentence: We use a microscope to make objects look (bigger/smaller/more interesting).

12. 1 Look carefully at the pictures showing Jackie using a microscope and preparing slides. Explain what she is doing wrong in each case. a b c d 2 Fill in the correct microscope magnifications in the table. 3 What does a stain do? Chose the best answer makes things in a specimen stand out better holds the specimen in place makes the specimen turn a pretty Colour stops the specimen drying out Magnification of eyepiece lens Magnification of objective lens Total magnification 510 540 10150

13. How to prepare a microscope slide Draw out a series of diagrams showing how to prepare a microscope slide. prepare a slide. Lower a coverslip onto the slide. Put the layer of cells on the slide. Put a drop of water on the slide. Take a thin layer of cells. First add few drops of water or solution on the microscope slide to avoid dryness and wilting Take a small piece of onion and using forceps (tweezers), peel off the membrane from the underside (the rough side). Lay the membrane flat on the surface of the slide Using a pin, lower a thin glass cover slip or cover glass onto the slide. Make sure there are no air bubbles (Fig. 1).

14. coverslippipetteslide specimen 7Ab7Ab 1 Fill in the crossword grid by answering the clues. Across 3 Slides and coverslips are made of this. 5 The name of the thing we want to look at under a microscope. 6 What you want to look at under a microscope is put on one of these. Down 1 What a microscope does. 2 Part of a theatre and part of a microscope. 4 A microscope has two types of these. 2 a The drawing shows a coverslip being put in place. Label the parts using the words in the box. b What do we use a coverslip for? Tick two reasons. to squash thick specimens to hold the specimen in place to stain the specimento stop the specimen drying out to magnify the specimento heat up the specimen I CAN... describe what a microscope does and how to use one describe how to prepare a slide. 12 Exploring Scienceedition© Pearson Education Limited 2008 42 3 1 5 6 a b c

15. 1 Each of the following sentences has at least one mistake in it. Rewrite each one, correcting the mistakes. a A coverslip is used to squash the specimen to make it thinner. b To start using a microscope, you should turn the focusing wheel so that the objective lens and the stage are as far apart as possible. c You should aim the mirror of a microscope at the Sun to make sure the specimen is well lit. d A stain is used to turn the specimen a pretty colour. e Microscopes have two lenses, the eye lens and the abject lens. f The magnification of a microscope is worked out by adding the magnifying power of the two lenses together. 2 You are given a microscope which has three objective lenses: ´15, ´20 and ´40. The microscope has four eyepiece lenses: ´2, ´5, ´7.5 and ´10. You need to use magnifications of ´30, ´100, ´300 and ´400. Which combination of lenses would you use to achieve each magnification? Draw a table to show your answer. 3 Jackie has made a slide of some of her hair. She wants to work out its width. She examines her slide under a microscope using a x5 eyepiece lens and a x20 objective lens. This is what she sees: a Work out the diameter of Jackie’s hair in real life. Show your working. b What is the round thing? c How could Jackie avoid getting round things like this in her slides? 14 Exploring Scienceedition© Pearson Education Limited 2008

16. YESI have enjoyed the lesson and learnt a lot and completed my class activity. SOMEI have understood some of the work and haven’t finished it all NOI have found it difficult to learn today and I have done very little work

17. Science Department Marking your work S trength Say what you have done well T arget This is something that you could do to improve your work and/or take the next step forward. E ffort a comment about your overall effort here. Sometimes this will be a number. 1- Excellent 2 – Good effort 3 – Satisfactory 4 - More effort needed P upil comment write your own pupil comment. It should show how well you think that you have understood the work.