Hand inside vacuum chamber experiment - GIF

[bruce.desertrat]

My 7th grade science teacher taught us the rule about "Add Acid To Water" quite graphically. He had a large Pyrex beaker (5 or 6 liter) with about a liter of Sulfuric Acid into which he poured about 250ml of water. The contents immediately started boiling vigorously. He took the beaker to the back of the class and stuck it in the big heavy sink, then came back up front and started talking about more of the subject. At the end of the class he said "I want to show you something"

He went back and picked up the beaker.

Still steaming .

That firmly fixed that rule in my head!

[mklotz]

My 7th grade science teacher taught us the rule about "Add Acid To Water" quite graphically. He had a large Pyrex beaker (5 or 6 liter) with about a liter of Sulfuric Acid into which he poured about 250ml of water. The contents immediately started boiling vigorously. He took the beaker to the back of the class and stuck it in the big heavy sink, then came back up front and started talking about more of the subject. At the end of the class he said "I want to show you something"

He went back and picked up the beaker.

Still steaming .

That firmly fixed that rule in my head!

The mnemonic helps me to remember

Add acid to water
Like a fellow oughter

[odd one]

Unfortunately, so many of these hands on real life demonstrations have been removed from the class rooms these days. It was the explosions, smoke and electrical arcs that kept my attention and got me thinking. I am so thankful I had teachers that were able/allowed to do those kinds of demonstrations back then. There is a huge difference between watching a video and seeing it first hand. Kids these days are missing out.

As to the original video and body experiments (though that video was a demonstration) - I remember when Col. (at the time) John Stapp came and spoke at our school. He was the first man to ride a rocket sled out at Holloman AFB. This is a man that gave his body for science, experiencing more than 40g's to help advance ejection seat technology. https://www.popsci.com/blog-network/...cket-sled-man/

[bruce.desertrat]

Unfortunately, so many of these hands on real life demonstrations have been removed from the class rooms these days. It was the explosions, smoke and electrical arcs that kept my attention and got me thinking. I am so thankful I had teachers that were able/allowed to do those kinds of demonstrations back then. There is a huge difference between watching a video and seeing it first hand. Kids these days are missing out.

As to the original video and body experiments (though that video was a demonstration) - I remember when Col. (at the time) John Stapp came and spoke at our school. He was the first man to ride a rocket sled out at Holloman AFB. This is a man that gave his body for science, experiencing more than 40g's to help advance ejection seat technology. https://www.popsci.com/blog-network/...cket-sled-man/

That reminds me of another demonstration in the same class, this time by a school resource firefighter, showing us the dangers of screwing around with gasoline. He had a steel container (from my dim memory of 7th grade) roughly the size of a insulated coffee cup. He pulled out a eye dropper, put one drop of gasoline, covered it and shook it up. Pulled off the cover and dropped a match in window-rattlin BANG!

This is much the same way our welding shop teacher taught us the difference between oxy, acetlylene and oxy-acetylene.

Filled a baloon up with oxy, touched it with a hot welding rod: POP!
Filled one up with Acetylene, touched it : FOOMP. Big yellow fireball, acetylene soot floating everywhere.
Filled one up with Ocy-Acetylene, then told us to pay close attention so we cold tell the difference...

He gave us a few minutes to regain our hearing and told us "THIS IS NOT SOMETHING TO PLAY AROUND WITH!"

(other lessons, like absently picking up a no-longer-red-hot piece of steel I'd been working on in the forge with my bare hand, because 16YO brain said "It's not red anymore, so it's not hot" he left for us to discover on our own... )

[Elizabeth Greene]

I remember many years ago talking to G. Harry Stine (author, etc.) about a skin suit that was NOT airtight. Seems as long as you support the skin with something like a compression sock it can handle vacuum.

This is an active area of research. The magic search keyword is "Mechanical counterpressure suit". Here's the state of the art as of ~2017.


The problem with them is they have to be super snug. That makes them a serious pain to put on. If your suit fits too loose anywhere where they aren't tight enough, you get a big Hickey. Mr. Jar guy above is an extreme case of that. He got the arm Hickey and, since there was no support preventing the jar from moving up, the Earth's atmosphere tried to squeeze his entire body into that jar like squeezing a tube of toothpaste. The only thing preventing that from happening (or more of his arm getting sucked in) was his (rather fragile) arm and wrist bones.

[odd one]

So they were on to something with the uniforms in Star Trek the Next Generation!

[Elizabeth Greene]

They were on something all right. Imagine being a starship mechanic and not having pockets. I'd literally die. In that case I mean literally in the literal sense. Someone would shove me out an airlock the 500th time I misplaced the little widget that realigns isolinear chips.