A commercial or DIY smoke cell for microscopy?

[Hobbyst46]

Hi All

Brownian motion is a fascinating phenomenon to observe and to demonstrate to kids. It can be viewed microscopically in milk (the fat particles) and other aqueous suspensions (pollen etc.), but also in smoke particles under strong illumination.
There was a commercial (?) smoke chamber, the Whitley Bay type, for microscopy. It requires a 12V source. And some other DIY descriptions on the web.
I anyone familiar with a good, reliable and inexpensive smoke cell for microscopy, using a compound microscope, not a stereo one?

[MicroBob]

Hi Hobbyst46,

you might look into catalogues for school science courses. In Germany this would be Phywe or Conatec (and probably some more). I have a lightweight microtome from Japan that is made by a japanese school supplier, Uchida. There are probably comparable companies in most bigger countries.

Bob

[Hobbyst46]

Thanks MicroBob,

keywords - smoke, brownian

Searched in Phywe but did not find anything,
searched Conatec but could not locate a site by this name that sells school lab devices,
Searched Uchida, but did not find anything (could not find a microtom either! perhaps it did not sell well),

The Whitley Bay cell still exists, but is slightly pricey for me, considering the handling and shipping, postage etc
Searched the Google space, and found a cell that appears to be a modified copy of the Whitley Bay, but was given a single negative review

I will keep trying. It ought to be a very simple and inexpensive gadget, but perhaps there is no demand for it nowadays...

[MicroBob]

Sorry, it is Conatex

With individual made small series school equipment "inexpensive" is relative. Usually the maker is not happy with his profits on it and for the buyer it is still very expensive. I think you will get a DIY solution running quicker and cheaper than a commercially made chamber, even if you have to pay for the making of some parts. It would be an interesting experiment for the pupils but you always have to have motivated teachers to actually use it in their classes.
Would it be possible to use disco fog instead of smoke?
This is the simple school microtome I bought for about 25€: https://us.vwr.com/store/product/888765 ... -microtome or http://www.neobits.com/uchida_yoko_162_ ... 84170.html I haven't used it so far but it seems ok for softer plant material.

[Hobbyst46]

Thanks MicroBob
Disco fog can perhaps preplace smoke since the particles scatter visible light.

[Suphot]

I would like to share easy DIY small “Smoke Cell” to observe Brownian Motion under microscope at 100X as follow;
1. Cut a cardboard strip about 3mm x 84mm to use it as a wall of Smoke Cell as show in the picture. This size will fit with 22mm cover slip. If the cardboard is quite thick and you need a higher cell, you may cut the cardboard about 5mm x 80mm strip.

[Suphot]

2. fold the strip to form a rectangle cell wall, join the strip together with scotch tape.

[Suphot]

3. This Cell wall should fit under 22mm cover slip, apply paper glue on top of this cell wall and put the clean 22mm cover slip on top of it.

[Suphot]

4. When we put this Smoke Cell over a microscope slide, it will be a small Smoke Cell that can be used to observe Brownian Motion.

5. To use this Smoke Cell, I setup microscope with Dark Field mode (if you have not a Dark Field patch, build one of it first). Adjust microscope brightness to about 80% to make sure that it is bright enough. Put some prepared slide under microscope and focus it with 10X Objective to make sure that Dark Field mode and the microscope focus properly. Remove the prepared slide and fill the Smoke Cell with smoke as show in the picture.

[Suphot]

Then carefully move this slide under microscope to observe Brownian Motion. Focus the microscope objective a little bit higher to see the smoke particles moving around. It will be easier to use Joss Stick as a source of smoke.

The smoke in the cell will last about 1 or 2 minutes, then we have to fill the smoke in the Smoke Cell again.

[Suphot]

This video capture Brownian Motion in Smoke Cell in the picture at 100X



https://www.youtube.com/watch?v=CMTPVus3LvU

[Hobbyst46]

Wow, Suphot!

Actually, I initially bought my microscope to look at Brownian motion, but was swept away from it by other microscopic charms and neglected it. In the past weeks I have been straining my mind to invent a smoke cell that can be easily fabricated from common stuff like microscope slides and coverslips and a matchbox. Planned to use drinking straws as smoke conduits in and out of the cell, and place a lens-capped 5mm bright LED sideways to as to shine a horizontal beam of light on the particles, etc... and became tired and changed the subject...

Now you just put forward this simple idea.

My problem would be darkfield at 100x. Did you mean a 100x objective? or a 10x objective plus 10x ocular? I get beautiful darkfield with my 6.3-10x-16x objectives, acceptable DF with the 25x0.45 objective but not at higher NAs.

Nice to know that someone else on the planet is interested in such gadgets!

Thanks!

[Suphot]

Hi Hobbyst46,

Sorry that I forgot to explain that 100X was 10X Objective with 10X Eyepieces.

You can try higher magnification Objective with your Dark Field setup, I have only 10X and 40X Objective, I am not try the 40X Objective yet, may be sometime later.

The Video clip that I show on Youtube was dimmer than what I saw from the eyepieces. Because when my smart phone capture video clip, it is not very good in low light, especially smoke particles in Dark Field like this.

You may start with 5mm x 80mm cardboard strip, the 3mm x 84mm that I use is a little bit too short. 5mm strip will easier to hold and more room for capture smoke inside it.

I hope you enjoy this experiment and share some video clip to other members


Suphot