Session Four (1.1.4): Sizes of Specimen and the Microscope

 Introduction

You need to be able to create a biological drawing of a cell and calculate its magnification or size in micrometres. Microscopes enable us to see things that are not visible or clear to the human eye.

Reading

Read through and make notes on pages 4 and 10 of your coursebook.

Note that these pages cover the parts of the microscope and how to calculate sizes of specimen using an equation.

 Links

Now work through the following resources:

WATCH – What is Microscopy? (YouTube) Links to an external site.

WATCH – Magnify (Twig) [Not available with sample course]

WATCH – Calculating magnification of drawings (YouTube) Links to an external site.

Activity

Answer the questions on page 10.

Skills

Ensure that you can draw a biological specimen following all of the following rules: clear and continuous lines, use of a sharp pencil, no shading, ruled label lines touching the specimen.

You must also be able to calculate magnification, using this formula:

Magnification = size of image/size of actual object

Note: millimetres are converted to micrometres by multiplying the value in mm by 1000.

WATCH – Paper 6 Tips & Tricks – Drawings full explanation (YouTube) Links to an external site.

Review

Complete Questions 4 and 5 on page 13. Check your answers.

Complete the self-evaluation checklist on pages 14 and 15. Go back and review any topics that you feel you need to study further.

Update your notes/flash cards as necessary.