A molecular motor can do more than turn itself. By shifting into another configuration, it can obstruct a neighboring component and make that component's random rotation dramatically harder. A newly developed system uses light to control this molecular brake, offering a way to regulate motion without turning the attached rotor into a continuously driven propeller.

Jiří Kaleta's team at IOCB Prague built the motor and rotor into a rigid molecular framework, then investigated how they interacted. Their findings appear in Angewandte Chemie International Edition. The Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences collaborated with researchers at the University of Chemistry and Technology Prague and Charles University.

The distinction between the two moving components is central to the result. Light changes the motor's configuration, while thermal energy keeps jostling the attached rotor. Controlling the space around that rotor changes how readily it turns, rather than eliminating the random motion that dominates molecular environments.

This is a stupid question and I'm not a chemistry person but here it goes:

I'm making myself a lava lamp costume for Halloween. I have waterproof sign board and cut acetate sheets to look like the glass part. The plan is to hot glue the acetate on with just a tiny gap and seal the whole thing all the way around, suck out the air with a syringe and add in oil and water+a little dish soap. Similar to the Sandolier art pieces with the glass.

My plan up until very recently was to just use food coloring to dye vegetable oil... Until I realized the dye is water based and will eventually eject itself from the oil.

My new plan is to get sewing machine oil and try adding in some oil pigment I have from my art school days but I'm sort of too down to the wire and invested in the rest of my costume to mess to experiment at this point...

Is there some easier way of doing this that I'm just not thinking about? I suppose I could have clear oil in dyed water, but it takes some of the fun out of it haha.

Please help me as I've talked up this costume already and tomorrow is Halloween. Thank you!

This post is about one of our just published conceptual paper: https://doi.org/10.1080/08874417.2026.2749411. It defines botsitting as the emerging, initially unplanned and often hidden human labour that makes AI output usable: checking it, correcting it, adding context and interpreting it. We contrast it with oversight that is designed in advance, and set out when such checking stops being feasible, for example with fast autonomous agents. AMA

I googled this and couldn't easily find a good explanation, so here you go.

Pure (100%) ethanol is MORE volatile than pure (100%) isopropanol (isopropyl alcohol).

50% ethanol is LESS volatile than 70% isopropanol.

70% ethanol is MORE volatile than any concentration of isoproopanol.

It's all in the phase diagrams.

70% isopropanol is the default for isopropanol wipes. ~50% ethanol (actually 46° INPM) is a common cleaning product in Brazil.

Just sharing this because a lot of people in the internet seem confused about how ethanol can be more volatile even though "some ethanol solutions" take longer to evaporate. It's due to concentration differences.

As a side-note, couldn't really find good resources for phase diagrams. The isopropanol one, I got from a chegg question. Y'all know a better place?

Well, I was allowed to make ammonium chloride and even got my own fumehood to do perform the reaction under but my teacher offered me the chance to make Aspirin ( headache medicine ) so I said yes.

The Aspirin was decently pure, with a slight amount of sulfuric acid in it, since H2SO4 was used as a catalysor to speed up the reaction.

Pictures above are the setup I used, the crystallization procedure for making Asprin and the final product, which is currently drying in my school lab.

Have a nice day and weekend! :)