# Magnification

After looking at cells under a microscope you may be asked to do a few calculations. These can be tricky but there is a great way to remember how to these calculations.

Below is the triangle you can use to help you learn and remember with the **3** equations needed. Simply remember it as **AIM!! **

Using the triangle is just as easy. Simply cover the one you want to work out and if they are next to each-other then you multiply and if they are on top/below each together then you need to divide to get your answer.

**Actual image** is the real size of the “thing” you are looking at (sometimes called **The Object**).

**Image Size **is the measurement, length/height/width, of the image you are looking at.

**Magnification **is how many times bigger something is being observed compared to its actual size.

When looking at cells we are looking at very small things so you may see some new measurements that you need to understand.

The common one to remember is that **1mm = 1000µm**

**Top Tip** – For any questions you get it usually helps to convert all your units to the same unit first.

## Example - Magnification

You are given an image of a cell and you measure the width to be **2mm**. You are told that the **Actual Image size** is **0.02mm** so you can now easily work out the magnification using the equation below.

Since they are already both in the same units you don’t need to convert them and just put them straight into the equation so you have.

**Magnification = 2/0.02 = 100**

This means the diagram has been **magnified 100 times **

## Example - Image Size

This time you have been told that the actual size of what you are looking at is 400**µ**m wide and that the magnification is x50.

We have we need to wok it out and can just substitute into the equation.

**Image Size = 0.4 x 50 = 2,000**

So the image size is **20,000****µm **or **20mm**

## Example - Actual Size

Here we have an image of a cell. It **measures 15mm wide** and the **magnification is x400.**

Using the equation we can work out what the real size of the cell is.

**Actual Image = 15/400 = 0.0375**

So the real cell is **0.0375mm wide.** You will want to convert this into **µm **so just times it by **1000** giving us a **width of 37.5****µm**

Once you can use the equations and convert units with ease you can also use the same process to measure sub-cellular structures in the cells and estimate the surface area etc…