⚛️ Atoms: The Tiny Everything!

What you’ll learn

1. Everything Is Made of AtomsUnderstand that atoms are the tiny building blocks of everything, how incredibly small they are, and that they get recycled over and over.Atoms are the tiniest building blocks that make up everything there is, from rocks and water to your own body. They are far too small to see — it takes a few hundred thousand of them lined up to cross a single human hair — so anything big enough to notice is a crowd of trillions. Your body holds about seven billion billion billion of them. Atoms never wear out, either. They get taken apart and rebuilt over and over, so an atom in your apple may once have been part of a dinosaur, a raindrop or a flower.
2. The Parts of an AtomLearn that atoms are made of protons, neutrons, and electrons, where each lives, and what makes each one special.Every atom is built from three kinds of piece. Protons and neutrons huddle together in the middle, in a clump called the nucleus, which holds almost all of the atom’s weight. Electrons stay out at the edges, moving too fast to pin down. Protons carry a positive charge, and how many of them an atom has is what decides which element it is. Neutrons carry no charge at all, which is where the word neutral comes from, and they help hold the nucleus together. Electrons carry a negative charge and are 1,836 times lighter than a proton — and pushing them from place to place is what electricity is.
3. Elements and MoleculesUnderstand that each kind of atom is an element, that atoms join into molecules, and that rearranging atoms makes new things, like water.Each kind of atom is called an element, and there are about a hundred of them. Nearly every atom in your body is one of only three: hydrogen, oxygen and carbon. Just like a box of LEGO bricks, a few kinds of atom snap together in endless ways to build everything else. When atoms join up, the group is called a molecule — some are two atoms, some run to thousands. Water is the famous one: two hydrogen atoms and one oxygen, written H2O. And rearranging the very same atoms, as carbon does, gives you soft pencil lead or hard diamond.
4. Empty Space and StardustUnderstand how Rutherford’s gold-foil experiment showed that an atom is mostly empty space, picture that emptiness with the stadium comparison, and learn that your hydrogen came from the Big Bang while almost everything else in you was made inside stars.Solid things are made of atoms, and yet each atom is mostly empty space, with a tiny nucleus in the middle and electrons far out around the edges. In 1909, Geiger and Marsden fired particles at gold foil and about one in twenty thousand was knocked off course, which is how Rutherford worked it out. If an atom were as big as a stadium, the nucleus would be a pea on the centre spot. Things feel solid because electrons push back against electrons. As for where the atoms came from: the hydrogen in you was made minutes after the Big Bang, and almost everything else was forged inside stars and scattered when they exploded.

Questions this course answers

Grounded in trusted sources

• Ernest Rutherford, "The Scattering of α and β Particles by Matter and the Structure of the Atom", Philosophical Magazine 21 (1911) — the 1-in-20,000 figure for GOLD foil is his, in his own words: https://www.chemteam.info/Chem-History/Rutherford-1911/Rutherford-1911.html
• NASA Imagine the Universe, "What is Your Cosmic Connection to the Elements?" — hydrogen from the Big Bang, carbon and nitrogen from small stars, calcium and oxygen from large stars, iron from supernovae: https://imagine.gsfc.nasa.gov/Images/teachers/posters/elements/elements2005_back.pdf
• Geiger and Marsden (1909) and the nuclear atom — Lawrence Berkeley National Laboratory, ABC’s of Nuclear Science: https://www2.lbl.gov/abc/wallchart/chapters/02/1.html
• BioNumbers (Harvard Medical School) BNID 105403, percentage of atoms in the human body — C, O, H and N are 99% of every atom in you: https://bionumbers.hms.harvard.edu/bionumber.aspx?id=105403
• NIST CODATA, proton-electron mass ratio = 1836.152673426: https://physics.nist.gov/cgi-bin/cuu/Value?mpsme
• USGS Water Science School, "Water, the Universal Solvent" — a water molecule is two hydrogen atoms and one oxygen: https://www.usgs.gov/special-topics/water-science-school/science/water-universal-solvent
• File:Atomic_resolution_Au100.JPG, Wikimedia Commons — the opening picture is a scanning tunnelling microscope image of a gold surface, public domain: https://commons.wikimedia.org/wiki/File:Atomic_resolution_Au100.JPG

Every Wunder lesson is built from real, reputable sources — never invented.

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