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When objects collide or are separated, aren't we really just witnessing tiny chemical reactions, all involving the absorption and/or release of energy?

by Andys 2y ago

LorenPechtel 2y ago
No. "Gamma rays" in modern scientific usage has a specific meaning: radiation coming from the nucleus or from annihilation reactions (electron + positron is considered a gamma source despite not involving a nucleus), not from the electrons. The energy bands actually overlap, you can't always tell whether a given photon is without understanding it's source. (The lowest energy gamma rays actually fall in the UV part of the spectrum.) And what they're saying is the energy of the lightning is acting as a particle accelerator. aka atom smasher. And there's a surprising level of atom smashing going on in the big thunderclouds.
vanderZwan 2y ago
I think that's a reasonable question, but no, I wouldn't say that that is the case. A chemical reactions is by definition the kind that involves changing the chemical composition of the molecules involved (yes, that's a bit handwavy, I'm not a chemist). The process that causes tape to produce to x-rays when peeled in a vacuum in this example does involve a change of energy states, but not in a way that we'd consider a change in chemical composition.
- Andys 2y ago
  What is holding the tape to itself, what is making it sticky, if not chemistry?
  - mgsouth 2y ago
    For pressure-sensitive-adhesive tape (cellophane tape) it's mainly fuzzy static cling--wetting and van Der Waal's forces [1]. Wetting is when two substances (even solids) intermingle at their interface. van Der Waal's force is when a negatively-charged area of one molecule lines up the a postively-charged area of another. [1] https://science.howstuffworks.com/innovation/everyday-innovations/adhesive-tape.htm https://science.howstuffworks.com/innovation/everyday-innova...
    - Andys 2y ago
      I see, so you're saying static cling "at a distance" is different to the interaction of positive and negative charges in a chemical reaction?
      - mgsouth 2y ago
        IANAChemist, but to extend the cheesy analogies chemical bonds are like joint custody in a divorce; two atoms share one or more electrons. If it's split more or less evenly then it's called a covalent bond. If it's stacked in one atom's favor then it's called ionic. If it's kind of in a gray area in the middle then its called a polar covalent bond. [1] Adhesion, even due to electrostatic or van Der Waal's forces, doesn't cause an electron to be shared [2]. To switch up the analogy (again, IANAC): as I understand it chemical bonds are like a couples thing; if you invite one you have to invite the other, and if you are interested in replacing a chemical bond with one of the atoms you need to first tear the couple apart. That's because chemical bonds share an electron; to share a particular electron with a new atom you need to stop sharing with the first one. (Sort of. I believe it's a lot more complicated than that, with group marriages and such.) Adhesion is more like a friendship thing. You might hang out together, but there's no intimiate involvement. The electronic bonds are still available, so each each substance can do its normal chemical reaction thing with other atoms. [1] https://en.wikipedia.org/wiki/Ionic_bonding https://en.wikipedia.org/wiki/Ionic_bonding [2] Despite my previous cheesy analogy, electrostatic adhesion is the real static-cling force, not van Der Waal's. (But electrostatic adhesion isn't what makes sticky tape sticky, van Der Waals is.) The former is between entire molecules or groups of molecules, one group having a total positive charge compared to the other. van Der Waal's is pin-point attraction between local differences in molecular charge distribution, and each molecule in total might be electrically neutral. For example, a neutral water molecule has two highly-positive areas near the Hydrogen atoms and a highly-negative region away from them.

When objects collide or are separated, aren't we really just witnessing tiny chemical reactions, all involving the absorption and/or release of energy?

by Andys 2y ago

When objects collide or are separated, aren't we really just witnessing tiny chemical reactions, all involving the absorption and/or release of energy?

LorenPechtel 2y ago

No. "Gamma rays" in modern scientific usage has a specific meaning: radiation coming from the nucleus or from annihilation reactions (electron + positron is considered a gamma source despite not involving a nucleus), not from the electrons. The energy bands actually overlap, you can't always tell whether a given photon is without understanding it's source. (The lowest energy gamma rays actually fall in the UV part of the spectrum.) And what they're saying is the energy of the lightning is acting as a particle accelerator. aka atom smasher. And there's a surprising level of atom smashing going on in the big thunderclouds.

vanderZwan 2y ago

I think that's a reasonable question, but no, I wouldn't say that that is the case. A chemical reactions is by definition the kind that involves changing the chemical composition of the molecules involved (yes, that's a bit handwavy, I'm not a chemist). The process that causes tape to produce to x-rays when peeled in a vacuum in this example does involve a change of energy states, but not in a way that we'd consider a change in chemical composition.

Andys 2y ago
What is holding the tape to itself, what is making it sticky, if not chemistry?
- mgsouth 2y ago
  For pressure-sensitive-adhesive tape (cellophane tape) it's mainly fuzzy static cling--wetting and van Der Waal's forces [1]. Wetting is when two substances (even solids) intermingle at their interface. van Der Waal's force is when a negatively-charged area of one molecule lines up the a postively-charged area of another. [1] https://science.howstuffworks.com/innovation/everyday-innovations/adhesive-tape.htm https://science.howstuffworks.com/innovation/everyday-innova...
  - Andys 2y ago
    I see, so you're saying static cling "at a distance" is different to the interaction of positive and negative charges in a chemical reaction?
    - mgsouth 2y ago
      IANAChemist, but to extend the cheesy analogies chemical bonds are like joint custody in a divorce; two atoms share one or more electrons. If it's split more or less evenly then it's called a covalent bond. If it's stacked in one atom's favor then it's called ionic. If it's kind of in a gray area in the middle then its called a polar covalent bond. [1] Adhesion, even due to electrostatic or van Der Waal's forces, doesn't cause an electron to be shared [2]. To switch up the analogy (again, IANAC): as I understand it chemical bonds are like a couples thing; if you invite one you have to invite the other, and if you are interested in replacing a chemical bond with one of the atoms you need to first tear the couple apart. That's because chemical bonds share an electron; to share a particular electron with a new atom you need to stop sharing with the first one. (Sort of. I believe it's a lot more complicated than that, with group marriages and such.) Adhesion is more like a friendship thing. You might hang out together, but there's no intimiate involvement. The electronic bonds are still available, so each each substance can do its normal chemical reaction thing with other atoms. [1] https://en.wikipedia.org/wiki/Ionic_bonding https://en.wikipedia.org/wiki/Ionic_bonding [2] Despite my previous cheesy analogy, electrostatic adhesion is the real static-cling force, not van Der Waal's. (But electrostatic adhesion isn't what makes sticky tape sticky, van Der Waals is.) The former is between entire molecules or groups of molecules, one group having a total positive charge compared to the other. van Der Waal's is pin-point attraction between local differences in molecular charge distribution, and each molecule in total might be electrically neutral. For example, a neutral water molecule has two highly-positive areas near the Hydrogen atoms and a highly-negative region away from them.