Workshop on slide making inspired by Robert Hooke
Saturday 9th November 2019
Chris Thomas started this workshop with an introduction to Robert Hooke, and then surprised us by telling us that we had to construct our own microscopes (with a 6-inch tube length and a movable stage for focusing) and illuminators (for reflected light), and then devise a way of measuring specimens, before moving on to examining some of the specimens that Hooke investigated. No instructions were provided, and marks would be given for each stage.
Chris Thomas introducing the workshop
The materials that Chris provided were eyepieces and objectives (from Barry Ellam’s bargain boxes at the East of England Meeting), some scored pieces of cardboard, sheets of white, black and decorative paper, rulers, specimen bottles with a hole in the top, clear sticky tape, Blu Tack and LED torches.
Materials for making microscopes
Chris brought enough parts for 6 microscopes, so we worked in pairs. Nigel Ashby agreed to be the judge and to mark the efforts of other members.
Jacky McPherson and Mark Shephard
John Tolliday and Joan Bingley
Pam Hamer and Danny Ferri
Paul Smith and Lisa Ashby
Tristram Martyn and Irma Irsara
Four cardboard microscopes
Cardboard microscope assembled by Chris Thomas
The way to make a movable stage for focusing was to space the ruler a little away from the stand (using blobs of Blu Tack, for example) and then wrap a strip of cardboard around the ruler, loose enough that it can be slid up and down but firmly enough that it does not slip. A roll of paper provided the body tube, with the black paper inside to reduce flare. The top of the specimen bottle provided a holder for the objective.
To show that their microscopes worked, some members held their their mobile phones just above the eyepieces to take photomicrographs.
Point of a pin [by Pam Hamer]
Blu Tack label [by Paul Smith]
Blu Tack label [by Lisa Ashby]
1p coin [by Joan Bingley]
1p coin [by John Tolliday]
The second stage was to devise a way to measure specimens using only the items on their tables. Some members devised their own systems of measurement, while others used screen dots and other parts of printed matter to measure in millimetres or micrometres.
The third stage was to examine and draw items similar to those that Robert Hooke observed, including cork, willow stems, charcoal, woven fabrics, razor blades, pins and cat fleas (Ctenocephalides felis, obtained from a veterinary surgeon by Lisa and Nigel Ashby). Members could use either the microscopes they had constructed, or the conventional compound and stereomicroscopes provided. Extra points were awarded for comparisons.
Specimens to be examined
Jacky McPherson drawing
Drawings of 2 fabrics by Jacky McPherson, comparing the weave patterns and spacing
Joan Bingley drawing
Drawings of linen and papyrus by Joan Bingley
Photomicrograph of linen fabric (4× objective, field width 3.7 mm)
Drawing of edge of razor blade by Joan Bingley
Mark Shephard and John Tolliday (foreground) drawing
Mark Shephard compared the weave patterns and spacing of 2 fabrics:
Drawing of blue flower fabric by Mark Shephard
Photomicrograph of blue flower fabric (4× objective, field width 3.7 mm)
Drawing of green tartan fabric by Mark Shephard
Photomicrograph of green tartan fabric (2.5× objective, field width 5.3 mm)
John Tolliday drawing
Drawings of cork and charcoal by John Tolliday, comparing the residual cell structure
Tristram Martyn drawing
Drawing of cat flea by Tristram Martyn
Paul Smith and Irma Irsara drawing
Irma told us that at home she uses an eyepiece fitted with a reticle that has grid of squares to help with her drawings.
Drawing of fabric fibres by Irma Irsara
Drawing of fabric fibres by Irma Irsara
Drawing of cat flea by Paul Smith
Pam Hamer drawing
Drawing of cut surface of cork by Pam Hamer
Drawing of edge of razor blade by Pam Hamer
Drawing of point of pin by Pam Hamer
Drawings by Lisa Ashby
While everyone else was busy drawing, Chris had a chance to relax before Nigel Ashby announced the winners.
Chris Thomas relaxing
Nigel Ashby announced the winners of the closely-fought competition.
Nigel Ashby announcing the winners
After the winners were announced, Chris Thomas requested feedback on the workshop and received some encouraging comments.
Some of the specimens were displayed on the Club’s large television, with images from a Chinese inspection camera.
Blue and white fabric
Report and most photographs by Alan Wood