How much resolution do I need for a microscope?

Scott Coutts scott.coutts at med.monash.edu.au
Tue Jun 10 01:07:54 EST 2003

JEDilworth wrote:
> If you want to see cells in a blood sample clearly and closely, then you
> might want to consider a scope with a 50X or 100X oil immersion
> objective.
> http://tinyurl.com/dwqy  (some information about when to use oil
> immersion)
> However, this will increase your expense. You can also use a 100X oil
> immersion objective to see those "boring" bacteria. You won't be able to
> see bacteria with anything lower than 100X oil. You will need to buy
> immersion oil also to put on your slides, and this can get messy. How
> old a child will be doing this?
> http://www.greatscopes.com/glossary.htm  This page explains microscopic
> terms and has a section on how to buy a microscope. It looks like a
> great page and you will probably want to look at this along with what
> we're telling you in these groups.
> I know everyone will jump on me now and tell me that it is not necessary
> that this child see these things, but if he's more interested in medical
> slides vs. slides made from nature, then this would be a worthwhile
> investment. 

Well, I wont! I think it's great getting kids involved in all of this stuff.

> I personally thought slides of onion skin (yawn) and pond
> water very ho-hum, but LOVED to look at blood smears and bacteria, etc.
> Maybe that's why I'm in microbiology and medical laboratory work.

Yep, onion skin is pretty boring, but pond things I reckon are great to 
look at! Not water, but sediment from the bottom and water plant roots 
etc - live ones, I mean, not fixed ones. THe roots I used to like to 
look at not because of the cells, but because you could see whole 
community of different organisms all living in, on and around the root 
hairs. I loved to look at all the different paramecia and motile algal 
cells buzzing around, with lots of different colours.  as well as 
insects at low power. The main reason I suggested the pond water is 
because it has lots of moving things to keep kids amused (since the 
youngest one that Harry mentioned was 6 y.o.). I didnt find most 
bacteria interesting... just coloured 'spots' (: I did find them more 
interesting to look at once I discovered phase contrast, dark field and EM.

I have to confess that I'm a bacterial molecular biologist, actually, 
rather than a microbiologist (: and I work on spirochaetes, so most 
other bactera are boring compared to them (:

> You may want to contact a medical school, if there are any near you, and
> see if any of the graduating students are selling their microscopes. It
> used to be required of med students to buy a microscope before their
> freshman year, and many only keep them during their four years at med
> school. Ebay might be another place to look.
> You also don't need to buy a new scope. Heck, most of the scopes I've
> used in my 29 years as a microbiology tech have been at LEAST 10 years
> old and some much much older than that (like 40-50 at one lab). As long
> as the lenses are not scratched and the scope has been well maintained,
> a used scope is fine.

Yep, I agree! In fact, I'd rather buy a good quality old microscope than 
a mediocre new scope.

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