You can try: “What are those lab containers called? Flasks?” Fewer words make questions easy to understand.

If you're goofing off with friends, you can invent your own words as you speak. You can say "What are those sciency glass thingies called again?" That's not English, but who's listening?

As an informal, joking way of speaking, any of these would be understood. The adjective for "related to science" is "scientific." We may invent words like "sciency" if we don't know the right word, but the right word is "scientific." A straightforward way to ask the question would be "What do you call those glass containers used in laboratories? Flasks?" Or, "what do you call those glass containers scientists use? Flasks?" A "flask" just means a glass container with a narrow neck. To be more precise we could say "lab flask," but if it's clear from context that we are talking about a scientific laboratory we could just say "flask." The kind with the flat bottom are "Erlenmeyer flasks." The kind with the round bottom are "Florence flasks." "Beakers" are another kind of glass container used in laboratories. Beakers are cylindrical in shape. They don't have a narrow neck. They have a little lip for pouring.