Where to buy ice cube trays & periodic tables

In our summer, teachers camp, we compare the workability of various metals based on their crystal structure, particularly the number of slip planes and amount of empty space ('gappiness') within the crystal.

I won't go all spoiler on you, but I do want to point out where we can get three of the tools that we use in the teaching of that topic.

First, there's the Sargent Welch student periodic table. The reason we particularly like this periodic table is that each square on the table shows the crystal structure (body centered cubic, BCC; face centered cubic, FCC; hexagonal close packed, HCP; etc) that each element takes in its solid form. I like to ask the students (or teachers if it's summer) which metals they already know are workable (usually gold, silver, aluminum, copper). We then check those metals' crystal structures to find them all FCC. From there, it's to the opposite end of the spectrum, to the least workable metals (titanium, cobalt, sometimes magnesium) which turn out to be HCP. (Check out the table in a large, printable form.)

Those periodic tables are available from Sargent Welch in all sorts of formats (8.5" x 11", 11" x 17" - even in French if that's what you need) or as a 50" x 38" poster.

While teaching that same topic, we also use a couple of types of ice cube trays for water bottle ice cubes. The first type of tray has very little empty space between the individual water reservoirs. This relates to the crystals with very little 'gappiness'. These trays can be found from time to time in the summer (sometimes on endcaps at WalMart in the summer, garden section). They can also be found reliably on Amazon, though, and the best deal I've found is a rainbow set of four, two-part trays for $9.99 (as of June 2015, anyway).

The other type of trays have more empty space between the water reservoirs, so they allow us to demonstrate the fact that crystals with more empty space within the slip planes. These tend to be more rigid, more fragile, and less easily found in stores. I don't know if that's because they require more plastic to produce or what, but I do know I haven't been able to find them anywhere in person for a few years. Amazon, however, has a bunch of options to buy them, the best of which gets you four, white plastic trays for $7.99 (again, as of June, 2015).