Not So Obvious Science Trick I Learned in Some Obscure Program as a Kid

This is an addendum to Catra's latest video related to fun science tricks:

(related image attached below)

I have a very hazy memory of being driven to some after-school science program in some remote school from where I normally attended. I think I was in middle school at the time. I remember my neighbor also went, and she was the only other person I know personally who also went to that random ass event; although, I am not sure whether she remembers it. The other students were from other schools.

It was just a day of science experiments, but I don't recall why I was there -- if I was chosen -- nor do I remember its purpose or official name; I don't even remember signing up for anything. Although, I'd bet it, at least, had something to do with that G.A.T.E. (Gifted and Talented Education) program. Parents just seemed to drop off their kid here to spend the day (and, spend the day we did; I recall leaving when the sun was setting and the brightness was partially blinding me with its red and orange).

Anyway, one specific experiment stood out to me and has continued to stick with me after all these years (I have graduated university, for reference): filling a rigid container with water while the container is upside down and partially submerged.

We were placed into a typical high school science classroom equipped with that smooth, matte-like table countertops and faucets (the faucets always stick out to me). The classroom had a distinct black and greyness colour to it with its walls and furniture. If it wasn't those two colours, it was glass or a silver metal, like the faucets or the rods of chairs and stools or the handles of cabinets.

We were placed into groups of two and given the following devices in the attached image below. We were asked to do our best to figure out whether we can fill up the rigid container using the displayed setup -- there was much less water than I drew. The palette was a black plastic and the water, the tiny bottle, and the syringe were clear. A tube was attached at the end of the syringe.

Looking back on it, it seems pretty obvious that there were only like 4 actions: suck water, push water, suck air, push air. But, my babey brain only thought of using the syringe solely for transporting water. The plan seemed to work if not for that infernal tube disrupting the seemingly fragile setup; the water was shallow enough that when the container was tilted due to the tube's insertion, the entry point could stop being fully submerged. Therefore, the setup seemed to me like it needed patience and precision, so you could partially reveal the mouth to air to pump tiny amounts of water to fill the container (otherwise, the water wouldn't go in due to air pressure (they needed to switch places somehow)).

This didn't work, of course, because natural forces work faster than I can pump water inside (i.e., water just flowed back out the moment air could flow in). I tried honing my precision over the course of the allotted time, and the teachers/adults gave us enough time that the students reached a point of exhaustion where they stopped trying and were just sitting around from the flatness of their results. I didn't stop, though, because I was super convinced my plan would eventually work -- I just had to be faster and more precise.

THE SOLUTION:

I just hinted at the solution. It's air! It's PV = nRT (probably idk it makes sense to me tho). Everyone knows PV = nRT :D (which I pronounce 'pivnurt') (oh, I just Googled it and it's actually called the Ideal Gas Law... of course >_>). Anyway, you were supposed to suck the air out of the container. Because the container is rigid, it won't crumple as you reduce the air pressure within it. To balance the reduction in air pressure and constant volume, water flows in. Yippie!

I was so flabbergasted at the solution, I had to try it for myself before the adults herded us into a different room for the next activity. Lo and behold, it does what they said it would do. Can you believe it?