Gramps
Harmless
Posts: 2
Registered: 25-9-2025
Member Is Offline
|
|
New Member
Thankyou for the invitation to your forum!
While still in high school, we ran across a book titled, "The Amateur Scientist".
In it were described some incredible experiments! Thus began a life of adventure into the hard sciences.
Years ago I acquired a 2000 ml filter flask with the intention of someday constructing a Crookes Tube.
Perhaps the time has arrived.
The first question that comes to mind is how to clean the flask in preparation to use as a vacuum vessel?
Solvents, baking or a combination?
Secondly, how to acquire AND APPLY phosphors that will register electrons?
I want to coat the bottom of the flask and also create a angled scale, perhaps on a microscope slide, to attempt to measure the charge-to-mass ratio.
I did find an online post from this forum about phosphors but could not locate it using the search command.
Appreciate any help! Thanks, Gramps
|
|
|
bnull
National Hazard
Posts: 886
Registered: 15-1-2024
Location: East Woods
Member Is Offline
Mood: 403 forbidden
|
|
Welcome to the forum.
Do not use the forum's search engine unless the search term is an uncommon word. Add "site:sciencemadness.org" to your search terms in Google or Bing
or whatever; that's the only way to see relevant results.
Flat-bottomed flasks are not the best to subject to low pressure. If your filter flask has thick walls or is appropriate to use at low pressure, which
amounts to the same thing, then you can make a Crookes tube with it. Sort of.
Is the flask bought new and never used or is it second hand? If new, wash it with some dish detergent to remove the usual finger grease (wear gloves)
and rinse a couple of times with distilled, deionized, demineralized or whatever pure water to remove the remaining surfactant and salts. If used, you
probably need to give it an acid bath to remove inorganic crud (citric or oxalic acid for rust stains, HCl for white crusts) or an alkaline bath to
remove grease and proteins, rinsing with water, then the detergent cleaning as usual.
Edit: Typos. Autocorrect is at it again.
V. Dulin (Electron Devices, p.162 or thereabouts) says that green phosphors are less tiring for the eyes while blue phosphors give better (analog)
photographs.
[Edited on 25-9-2025 by bnull]
|
|
|
Sir_Gawain
National Hazard
Posts: 523
Registered: 12-10-2022
Location: southeast
Member Is Offline
|
|
For the phosphor, some people have had success with the phosphor found inside fluorescent light bulbs. Simply brush the powder off the inside walls
and mix it with acetone. Then coat the bottom of your flask with this solution and let it dry.
|
|
|
Gramps
Harmless
Posts: 2
Registered: 25-9-2025
Member Is Offline
|
|
bnull,
Thanks for the directions to access the library.
The flask is heavy duty with thick walls and has a sidearm for vacuum separations. I bought it in an antique shop ($30 ) and, other then being a little dusty, appears to have never been used.
Sir_Gawain,
At least one u-tube clip I viewed used the florescent tube phosphor but they didn't explain how to transfer it to the bottom of the flask. Thanks for
the tip!
I wonder, will the phosphor dissolve in the acetone?
Do you think it will remain in place after the acetone has evaporated?
I haven't priced other phosphors but that's probably the cheapest way to phosphor the flask.
P.S. sorry, not sure how to correctly post a quote and make a reply. When I highlighted a portion and hit "quote" the entire post was quoted. Then I
didn't see a place to reply.
Gramps
|
|
|
bnull
National Hazard
Posts: 886
Registered: 15-1-2024
Location: East Woods
Member Is Offline
Mood: 403 forbidden
|
|
Quote: Originally posted by Gramps  | | P.S. sorry, not sure how to correctly post a quote and make a reply. When I highlighted a portion and hit "quote" the entire post was quoted. Then I
didn't see a place to reply. |
The "quote" button is actually "rquote", which includes the whole text of and a link to the original post.
If you want to write a quick reply, simply copy the portion of the post you want to reply to, write quote inside square brackets on that box at the bottom of the page, paste the text, then write /quote inside square brackets and write your reply after it. I use this to
reply to the last post (not a forum rule, it's just my preference), especially when there are no files to be attached.
| Code: | [quote]Welcome to the forum.[/quote] |
| Quote: | | Welcome to the forum. |
"rquote" is good when the original post is farther away, when there is a chance of confusion or ambiguity as to where the original post came from or
who wrote it, as it includes a link to said post. Just hit the quote button on the corner of the post, edit the text using the tools of the reply
page, then write your reply after /rquote.
| Code: | [rquote=703396&tid=161305&author=bnull]Welcome to the forum.[/rquote] |
Edit: By the way, you have 24 hours to edit your own post after publishing. After that, it will stay as it is. It helps when you have afterthoughts,
forgot to attach a file, or simply missed some typos.
[Edited on 30-9-2025 by bnull]
|
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
