OFFICIAL50 Why does the professor say this:

[00:01.00]NARRATOR: Listen to part of a lecture in an ancient history class.[00:06.29]FEMALE PROFESSOR: OK, last time we were discussing trade and commerce during the Bronze Age …[00:11.62] And I said a little over 3,000 years ago there was quite a lively trade among the countries along the Mediterranean Sea—[00:21.15]people were making objects out of bronze, and they were using bronze tools to make other goods, [00:26.70] and they developed trade networks to trade these goods with other countries around the Mediterranean … [00:32.11]One of the things they traded was glass …
[00:35.98] And recently there was an archeological excavation in Egypt—on the Nile River, around where it enters the Mediterranean Sea—where they discovered an ancient glass factory. [00:47.26]Robert?[00:48.19]MALE STUDENT: I thought our textbook said that the Egyptians imported their glass from other countries.[00:53.28]FEMALE PROFESSOR: Well, until now that's what the evidence seemed to suggest. [00:56.90] I mean, we had some evidence that suggested that the Egyptians were making glass objects, uh, but not glass.[01:03.60]MALE STUDENT: OK, am-am I missing something? [01:05.95]They're making glass, but they're not making glass.
[01:09.22]FEMALE PROFESSOR: I said they were making glass objects, right? [01:12.66] You see, it was previously thought that they weren't actually making the raw glass itself, that they were importing unfinished glass from Mesopotamia—um, which today is a region consisting of Iraq, and parts of Syria, Turkey, and Iran—and simply reworking it. [01:30.33] Most archeologists believed that the glass factories were in Mesopotamia because that's where the oldest known glass remains come from. [01:39.77] You see, there were two stages of glassmaking: [01:42.38] the primary production stage, where they made disks of raw glass…[01:47.63] Uh, an- and then there was the secondary stage, where they melted the raw glass, the glass disks, and created decorative objects or whatever.[01:58.44]And from this new Egyptian site we've learned that the primary production stage had several steps. [02:05.02] First, they took quartz—a colorless, transparent mineral—and crushed it. [02:11.59] Then they took that crushed quartz and mixed it with plant ash; [02:16.30] uh, “plant ash” is just what it sounds like—the ash that's left after you've burned plant material. [02:22.25] They slowly heated this mixture, at a relatively low temperature, in small vessels, um containers, like jars, made out of clay. Uh, [02:31.32] and that yielded a kind of glassy material…
[02:35.52] They took this glassy material and ground it up into a powder, and then they used metallic dye to color it…[02:43.99] After that, they poured the colored powder out into disk-shaped molds and heated it up to very high temperatures, [02:53.35] so that it melted. [02:54.70]After it cooled, they'd break the molds, and inside…there were the glass disks. [03:02.38] These disks were shipped off to other sites within Egypt and places around the Mediterranean. [03:08.09] Then, in the secondary phase, the disks were reheated and shaped into decorative objects. [03:14.62] Susan?[03:16.30]FEMALE STUDENT: So what kind of objects were people making back then?[03:19.37]FEMALE PROFESSOR: Well, the most common objects we’ve found—mostly in Egypt and Mesopotamia—uh, the most common objects were beads; [03:27.74]one thing Egyptians were very, very good at was imitating precious stones; [03:33.22]they created some beads that looked so much like emeralds and pearls that it was very difficult to distinguish them from the real thing. [03:41.47] Uh, and-and also beautiful vessels, uh, with narrow necks; [03:48.10] they were probably really valuable, so they wouldn't have been used to hold cooking oil or common food items; [03:54.26] they were most likely used for expensive liquids like perfume.[03:58.06] Now the glass made at this factory was mostly red; to get this red color, they used copper; in a sophisticated process. [04:07.22]Of course, any kind of glass was very valuable, so these red bottles would only have been owned by wealthy people. [04:13.42]In fact, because it was so difficult to make, and sort of mysterious and complicated, it was probably a product produced for the royal family, 04:22.13]and they probably used glass to show their power. [04:25.32] Also, beautiful, expensive objects make great gifts if you're looking to establish or strengthen political alliances…[04:33.41]and it's quite possible that ancient Egyptians were actually exporting glass, not just making it or importing it. [04:39.84] The trade with Mesopotamia was probably a friendly, mutual trade…because, uh, Mesopotamian glass was usually white or yellow, [04:47.64] so Mesopotamians might have said something like, “We'll give you two white disks for two red disks.” [04:54.31]There’s no proof of that, uh—at least not yet…