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How to use the microscope

We recommend a small usb type microscope with the highest possible resolution with a 5mp camera, or better if available.

You will have collected the sample of plankton and plastic which are now on the 50mm diameter filter paper. The filter paper is transferred to a 90mm petri plate, and sits on top of a 5mm squared plastic 50mm disc.

You can now lower the camera down to within a few mm of the sample, try not to touch the sample with the microscope.  Now use the focus dial, it might be marked ZOOM, rotate until the image comes into focus.

If you move the petri plate slightly back and forward as you focus the microscope, it can make this task easier.  You want to focus in on surface objects.  The 5mm square grid lines below the filter paper will allways be out of focus,  but they are still clear enough to be visible.

The 5mm square grid allows you to do two things;

1. Using the software provided you can set the scale

2. You will know where you are on the filter paper, so it can be covered without missing a section, or counting the same part twice

Once everything is set up, and the microscope is in focus,  the vertical field of view as displayed on your computer display, should be almost 5mm.  This dimension is equal to 5000 um. The line thickness is about 150 um, and once you have focused in, you will be able to see objects down to 20um.  Below 20um the resolution is not sufficient to distinguish any objects.

You can now start to scan along the grid, and video the process.  At the same time manually record what you see.


Life on earth depends upon healthy Oceans, we have 10 years to stop toxic chemical pollution, or life on earth may become impossible

Dr. Howard Dryden, CSO

Goes Foundation

Roslin Innovation Centre
The University of Edinburgh
Easter Bush Campus
Midlothian EH25 9RG