This project is interesting in its own right, and links to a cool tool by the same author

http://blog.jgc.org/2012/01/international-object-sizing-tool...

for showing the size of photographs, which I just told my Facebook friends about and printed out for my children, who are practicing photography.

The heavy-duty version of a periodic table table is that made by Theodore Gray,

http://www.theodoregray.com/periodictable/

who is quite a fan of the periodic table.

http://periodictable.com/

Recommended reading: his tale about the construction of that table: http://theodoregray.com/PeriodicTable/History.html

Cool project! A few easy ideas:

Zn: outside of a zinc/carbon battery

He: balloons

Ni: welding rods

Am: smoke detector sensor

Pt/Ir: spark plug central electrodes (your mechanic's more likely to give you an old spark plug than a whole cat converter ;)

Hg: thermometer

Trying to think up easy/cheap ways to get elements is quite fun

Very neat idea. Reminds me of birding (finding and recording birds seen). If he were to find a radioactive item, presumably the bottles (glass, with polypropylene and polyvinyl tops) wouldn't work. Wonder what he'd use then. Also calls to mind the Elements exhibit at the Griffith Observatory in Los Angeles (http://www.griffithobservatory.org/exhibits/bhallofsky.html).

What do you think is hardest to obtain element with a relatively low atomic number?

Group I metals are highly reactive and get more so as you increase atomic number, so if potassium counts as "low" that would be my bet... of course it would depend what the rules are.

What's low? Need it be pure? What tools do you get? Can you spend money?

For DIY, I'd guess helium.

Get it from a party balloon?

May be hard to keep for longer than a day or two though.

Scandium?

I'd say fluor because it's damn reactive (and thus, dangerous).

Nice project. I really like the book you used the poster from. My boys devour it. The quirky little elements remind me of OS-tans.

I wanted to make something similar with my boys. How did you choose to attach the vials? Glue?

Great project!

Loops of copper wire just under the lid.