Dating & Stratigraphy
📋 What it is
Deeper layers are usually older; scientists also use methods like carbon dating to find how old a find really is.
🗣️ Coach says
How do we know something is 5,000 years old? Two clues: layers (stratigraphy) — deeper usually means older — and lab tests like carbon dating that measure how long something has been decaying. Together they build a timeline you can trust.
🧠 Memory hook
Deeper = older (usually). Carbon dating checks the number.
😂 Giggle
The radiocarbon dating lab is the only place where having chemistry determines your age.
😲 Whoa!
Radiocarbon dating works because living things absorb carbon that slowly “ticks down” after death — like a natural stopwatch.
🗺️ Choose your path through the dig. There’s no way to lose — a wrong turn just sends you back to try again.
You find two objects in an undisturbed dig — one deep, one near the surface. Which is likely OLDER?
Dead end — in undisturbed ground, layers pile up over time, so the DEEPER layer was laid down earlier (it’s usually older).
To be sure of the actual age, you send a sample to the lab.
Careful — looks can fool you. Carbon dating measures how long something has been decaying, like a natural stopwatch, to check the real age.
Layers give you the ORDER (deeper = older) and carbon dating gives you the NUMBER — together, a timeline you can trust.
🧠 Say it back: In an undisturbed dig a deeper layer is usually older because layers pile up over time — lower layers were laid down earlier (the law of superposition).
🧪 Try it! (2 minutes)
Stack three books and explain which “layer” was placed first — the same logic archaeologists use.