Help me with teaching, please!

[Jalapeñomel]

I’m doing a demo, and I need to think about questions or thoughts students may present.

So please answer these questions, no judgements if you don’t know, your thoughts or ideas are what I need, and they don’t have to be correct!

1) Do you know how a vacuum bag for clothes or food work?
2) What do you think it means to vacuum seal clothes or food?
3) How do you think that relates to chemistry or things we’ve studied in class thus far?

[ProfessorArtNerd]

1) I think I do
2) vacuum sealing means to suck the air out of the bag
3) by eliminating the air, you prevent certain chemical reactions from happening, like spoiling or oxidizing. Maybe?

[wildfloweragain]

I have no thoughts except "it sucks."

You teach high school, right? I can ask my middle schooler and the high schooler who is home right now and see what they might say.

[erbear]

I think vacuums suck the air out, so to vacuum seal something means to remove the oxygen. No idea how it relates to chemistry, lol, but I assume you do

[VillainV]

1. Yes
2. Suck the air out of a bag or container, then seal it so air won’t get back in
3. I guess I think of it more in terms of physics. If you remove the air from a fixed-volume vessel (like a glass jar) the other stuff expands to fill the empty space (so something like a marshmallow will puff way up).

[wildfloweragain]

High Schooler: take out the air, make it so air won't get in.

relates to chemistry: "...something about gas"

unfortunately, that is the high schooler, who is currently in honors chemistry. And his first answer was "I don't know, you're the teacher. Isnt that your job to tell me?"

Accurate high schooler response, I guess.

[wildfloweragain]

Middle schooler: use the vacuum to take the air out. no idea how the seal works.

how relates to chemistry: it moves atoms.

[wildfloweragain]

Both kids were confused about the difference between the first 2 questions.

My oldest is way more into chemistry and wants to be a chemical engineer/astronaut. But they aren't home.

Robotics build season...

[Jalapeñomel]

Mar 5, 2023 12:59:55 GMT -5 VillainV said:

1. Yes
2. Suck the air out of a bag or container, then seal it so air won’t get back in
3. I guess I think of it more in terms of physics. If you remove the air from a fixed-volume vessel (like a glass jar) the other stuff expands to fill the empty space (so something like a marshmallow will puff way up).

Chemistry and physics are best friends!

[Jalapeñomel]

Mar 5, 2023 13:00:09 GMT -5 wildfloweragain said:

High Schooler: take out the air, make it so air won't get in.

relates to chemistry: "...something about gas"

unfortunately, that is the high schooler, who is currently in honors chemistry. And his first answer was "I don't know, you're the teacher. Isnt that your job to tell me?"

Accurate high schooler response, I guess.

Hah! I get this all the time, and my answer: “my job is to help you find the answer, not to tell you. Because I could tell you a hundred times, and you’d still not know!”

[sonrisa]

Mar 5, 2023 12:45:53 GMT -5 Jalapeñomel said:

I’m doing a demo, and I need to think about questions or thoughts students may present.

So please answer these questions, no judgements if you don’t know, your thoughts or ideas are what I need, and they don’t have to be correct!

1) Do you know how a vacuum bag for clothes or food work?
2) What do you think it means to vacuum seal clothes or food?
3) How do you think that relates to chemistry or things we’ve studied in class thus far?

1 + 2) Maybe, I guess? I personally have never used one, but I'd think something about negative pressure to remove the air from around the item (leaving the plastic in contact with the item), then the two layers of plastic are melted at fused together to seal it. 

3) (a) Oxidation plays a big role in decay so removing oxygen should slow that process.

(b) I'm guessing if you vacuum seal the wrong things, contact between the plastic container and the item could either effect the item (as plastic leeches in) or the container (if, say, an acid in the food reacts with the plastic and breaks it down).

(c) Oxygen is also necessary for all living things, so while the standard way to stop mold/mildew growth in packaged goods is to include one of those desicant (sp?) packages (again - chemistry) I would think removing oxygen slows the grow of microbes like mold as well. And respiration is a kind of chemistry

[Jalapeñomel]

Thank you everyone!

[sporklemotion]

Thoughts and prayers for all of the “suck” jokes headed your way (or is that just my students?)