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RE: Electric Hula Hoop

Andrew J — Wed, 13 Jan 2021 14:54:27 GMT

The great thing about lockdown is that people have plenty of time on their hands and come up with wacky, brilliant ideas such as this. Awesome.

RE: Laser Microscope Experiment

bonzadog — Fri, 30 Oct 2020 16:36:27 GMT

An interesting experiment. But probably Trump would not believe it...he is anti-science.

RE: TempMeter : Measuring Temperature with a Brass Rod

aspork42 — Fri, 23 Oct 2020 05:35:06 GMT

Cool experiment!

Thermal expansion is one of those things that I’ve often wondered about and not considered “solved”. Things like bridges just are forced to “deal with it” by using expansion joints. But we’ve also learned how to use it to our advantage with things like bi-metallic strips in thermostats...

RE: Electric Hula Hoop

Workshopshed — Tue, 13 Oct 2020 06:40:17 GMT

What a great project, love the smoothness of the motion.

RE: Laser Microscope Experiment

dubbie — Wed, 30 Sep 2020 12:37:20 GMT

Looks a fun experiment. I might have to try this out.

Dubbie

RE: Where Did My Volts Go?

dubbie — Wed, 30 Sep 2020 12:32:20 GMT

Nice experiment. Just shows that when we think we are measuring the real world, many times we are not.

Nice boat too.

Dubbie

RE: Where Did My Volts Go?

hlipka — Mon, 28 Sep 2020 21:23:20 GMT

I'm pretty sure that these multimeters should never ever get connected to live mains... Its a good idea to keep the camera as a shield between the meters and your eyes ;-)

RE: Laser Microscope Experiment

jw0752 — Mon, 28 Sep 2020 18:49:30 GMT

Fascinating simple experiment. I've got to try this. Even if the images aren't perfect it will be neat just to confirm the presence of the little beaties in the water.

John

RE: Laser Microscope Experiment

balearicdynamics — Mon, 28 Sep 2020 18:40:51 GMT

Maybe a video may help. Anyway, the proof of concept is interesting, but I think it is more probable you see the diffraction of the microbes instead of the cells themselves. The reason that probably you see few or nothing, due to a couple of processes that are typical of a microscopist:

1. Take a few grass or hay (better hay) and boil it for some minutes in water. Public water normally had chlorides insides that are dangerous for most of the monocellular life in the water. Then keep the boiled water with the other stuff (also some terrain may help)

2. Leave the infusion for some days, at ambient temperature. Then redo the experiment. Lots of paramecium, amoeba and other things magically appear!

Well then still there are some difficulties due to the light colour and the natural transparency of the microorganisms. You can solve this issue with a couple of products. One is the Eosin disinfectant solution. Put one drop in about 100 ml of infusion; it is an alcoholic solution so too much can damage the ecosystem you have created. The Eosin is an acid colourant that will change the colour of your cells (mostly the nucleus) without damaging them and keeping them alive. Another better alternative is the Methyle blu that can colour also the cells body. As far as I know, Methyle blue is present in some anti-inflammatory pills (your pharmacist can suggest you the cheap medicine that contains the component as the active principle.

Remain the doubt of what can be the contrast level using a laser (normally those keychain lasers are about 430-480 nm). But I think it is worth to try.

Enrico

RE: Radioactivity fun!

Jan Cumps — Fri, 25 Sep 2020 11:19:46 GMT

When I was in the army 2nd half of the 80s and moved to West-Germany, we all had an aluminum tube with a clip in our jacket pocket. To be worn all time when in duty.

If you unscrewed it, there was a valve in there, to collect the radiation level over time. There was nothing else in there except protection to avoid the tube from breaking.

They were not supposed to be used for checking individual soldier's levels. Would be collected for the whole battery together without info on who used a particular pen.

I tried to google for an image but didn't get a result that looked like the thing yet.

edit: this is the closest I could find:

[View:/resized-image/__size/358x498/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-a13cf54f-136c-4ae4-b294-d4214d9a785e/4861.contentimage_5F00_193183.png:358:498] [View:/resized-image/__size/512x497/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-a13cf54f-136c-4ae4-b294-d4214d9a785e/6507.contentimage_5F00_193184.png:512:497]

Edit edit: also had something like this in the same pocket, but also in a aluminum pen-style tube:

[View:/resized-image/__size/620x620/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-a13cf54f-136c-4ae4-b294-d4214d9a785e/4477.contentimage_5F00_193185.png:620:620]

That's for when you become victim of nerve agent.

Because in that case you have no muscle control, you have to hope that someone sees you, finds the pen in your pocket and shoots the antidote in your upper leg through your pants.

Then they have to hang the pen on the outside of your pocket, to indicate you've been antidoted. Because two of these injections aren't good-for-ya.

RE: Radioactivity fun!

jc2048 — Fri, 25 Sep 2020 10:18:28 GMT

That's an interesting looking G-M tube. I've got one that I bought years ago (1970s - they were sold as

'surplus' at the time, so I don't suppose it cost me very much), but I never did anything with it.

[View:/resized-image/__size/450x600/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-a13cf54f-136c-4ae4-b294-d4214d9a785e/contentimage_5F00_193182.jpg:450:600]

This one was intended for use with a piece of British civil defence equipment. It has a rubber boot around

it to give some protection and the base is in the form of a plug with two terminals. That allowed the tubes

to be changed easily [from looking online, it seems that there was also a specialised one that had a tray

for testing drinking water samples].

Helpfully, it has the operating voltage printed on it. Perhaps I should give it a try and see if it works.

RE: DIY OHM-METER & VERIFYING WHEATSTONE BRIDGE CONDITION

jw0752 — Tue, 15 Sep 2020 15:02:48 GMT

Hi Aabhas,

You have done an excellent job with this presentation. Simple and properly explained down to the foundation is always the best approach. We have a wide range of people, interests and abilities on the forum and we appreciate great projects like yours.

John

RE: DIY OHM-METER & VERIFYING WHEATSTONE BRIDGE CONDITION

aabhas — Tue, 15 Sep 2020 06:56:33 GMT

My blog submission for Project14 after a long long time ,a simple Project this time

RE: Radioactivity fun!

jw0752 — Tue, 15 Sep 2020 05:41:04 GMT

This is a great experiment and I enjoyed reading about it. I was wondering if you can give a little more background on how you measured the 68k events over a 38 hour period. When I was younger they were still doing atmospheric testing of nuclear weapons. At the time I bought a Geiger counter so that I could see if I could detect a difference in the background radiation after the tests were performed. I also wanted to see if I could detect any change in the radiation levels in the rain or snow. I kept a pretty consistent log over several months but I never saw a measurable change. I still have the Geiger counter and it still works. For radiation sources I have harvested a little Americium from junk smoke detectors and I have the face of a 1940s watch that had florescent numbers that were laced with radium to make them glow in the dark. The watch face still has a fairly high rate even after 80 years though it no longer glows in the dark.

John

RE: Voltage Drop Bonus Content

jw0752 — Mon, 14 Sep 2020 22:25:20 GMT

Very nice to have an auto ranging Fluke so you don't blow up your meter when the voltage jumps from mV to 119 V. This was a great illustrative addition to your entry.

John