Friday, March 02, 2012
Science Friday: Atomic Construction
... She also noticed that the atomic weight was written under each elements' symbol in the Periodic Table. Each box had the atomic number at the top center of the box--so 6 at the top of carbon. Then in the middle of the box was the symbol for the element--so a C for carbon. Then at the bottom middle was the atomic weight.
So the number at the bottom of carbon on the Periodic Table was 12.0107 because almost all the carbon on the earth is carbon 12, with its 6 protons and 6 neutrons. There's much less carbon 14, with 8 neutrons. She remembered that the book also wrote it slightly different some times. Sometimes the C had two numbers written just to its left, the mass number on the top (like 12 for carbon 12) and the atomic number on the bottom (like 6 for carbon).
She got it. It wasn't interesting in the slightest, but she got it. It was certainly enough to earn her a good night's sleep. Hopefully she wouldn't have any dreams about chemistry this time.
No such luck. She didn't actually realize she had fallen asleep. She had laid her head down on the desk in her room and nodded off. When she lifted her head back up, she thought she had re-awoken.
In reality, she was still asleep, her head still laying down on the desk. So it didn't seem unreasonable that she started to shrink, smaller, smaller, smaller. Soon the seat of her chair was a vast brown plain. Then she was seeing what must have been the cells of the trees from which the chair was made.
Down, down, down, she fell into the nucleus of a wood cell, then into its chromosomes and DNA. Then she was just falling. It was a vast empty space until finally she spied a huge ball of some sort directly beneath her. She bounced a couple times and finally was just sitting on top like she was on a bean bag.
"It's a proton," Spruce yelled up at her from a platform off to the side. It didn't occur to her in the dream to ask how he got there.
"Yeah?" she asked.
"Yeah. They're building a hydrogen atom. Want to help?"
"OK," she said. "What'll we do?"
"We need an electron. Hydrogen. Atomic number one. One proton, one electron."
"Any neutrons?" Stefanie asked.
"Nope. Just one and one. Well, there is..."
"Here are some," she interrupted. She had found a set of shelves with small balls in them, and with that, she lobbed one of them toward the big proton ball she had been sitting on. The small electron immediately started swirling in a sphere around the proton nucleus.
"And that's how it's done," she continued. "Hydrogen. Next!"
"OK," Spruce said and looked down at his chemistry book. "Looks like helium is next, atomic number 2."
"Isn't that the stuff you put in balloons for birthday parties, that makes your voice go high and squeaky?"
"Yeah," he answered. "It's two protons, two neutrons, and two electrons."
"I didn't notice that panel before," Stef said. Sure enough, there was a panel with a button for protons and a button for neutrons on it. She pressed the proton button twice, then the neutron button twice and the four particles appeared. "So now we just need two electrons."
Spruce picked two of the small electrons from the shelf and lobbed the one and then the other. Both of them swirled together in a sphere around the four particles in the nucleus...