By 200 million years after the Big Bang, the Universe had become a very dark and cold place. Then things started to change. First, dust and gas formed. Then stars emerged from these clouds of dust and gas. Those early stars led short lives and produced many of the chemical elements of the periodic table in their deaths. Today you’ll learn how stars first formed and how their deaths provided the chemical diversity necessary for even more complex things.
Driving Question: How were stars formed and what happens when they die?
- In the years following the Big Bang, there was a whole lot of nothing in the Universe. On the rare occasion there was a clump of something, gravity got to work! Little pockets of crowded hydrogen atoms eventually lit up into the Universe’s first stars. Burning all that hydrogen created helium, which created carbon... and neon, oxygen, silicon, and iron. But once those stars started running out of fuel, things got interesting! They died dramatically in a massive explosion that released all those atoms out into the Universe. You have dying stars to thank for all the elements on the periodic table.
Word of the Day: Chemical Element
- Definition: A fundamental type of atom, distinguished by varying numbers of protons and electrons and having unique physical properties.
- Many chemical elements are formed as products of dying stars. Hydrogen, helium, and carbon are abundant in the Universe, but the heavier elements are rarer, like gold, silver, platinum, and uranium. These rare elements come from extremely energetic and rare events, like the collision of two large stars!
Lesson
- Go to Khan Academy and watch the video Crash Course Big History: Stars & Galaxies.
- John and Hank Green explain the process by which stars are formed, including our own star, the Sun. They’ll also describe the death of stars—these explosions that release new chemical elements into the Universe. Keep track of the key ingredients necessary for star formation and the creation of complex elements.
Historian’s Journal Prompt
- Why do hospitals today fight infections with equipment embedded with silver?
- For hundreds of years, physicians have written about the healing properties of silver. I’m sure you’ve heard the phrase “born with a silver spoon in your mouth.” Did you know it’s not necessarily about being rich, but about being healthy?! In the 18th century, babies fed with silver spoons were thought to be healthier than those fed with spoons made of wood and other materials.
- Go investigate the kinds of medical equipment being used to fight the coronavirus... and see if you can find the silver! However, don’t forget to continue to use your claim testing skills. Think critically about any claims about silver’s “magic” properties!
