Is the Cat Awake or Asleep... or Both?
In 1935, a scientist named Erwin Schrödinger imagined a cat inside a closed box. Until someone opens the box, is the cat one thing, the other, or somehow both? It sounds silly, and that was exactly his point! In this unit, you'll explore one of the most famous thought experiments ever, ask big questions about what's real, and design a thought experiment of your own.
This is a philosophy unit, just like the Allegory of the Cave. Plato and Schrödinger lived 2,300 years apart, but they both used imagined stories to ask: How do we know what's real?
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Meet Schrödinger
Who was Erwin Schrödinger?
Erwin Schrödinger (say it: SHROH-ding-er) was a physicist born in 1887 in Vienna, Austria. He was one of the scientists who invented quantum physics, the science of the tiniest things in the universe, like atoms. In 1933, he won the Nobel Prize in Physics, one of the biggest awards a scientist can win.
Quantum physics has some very strange rules. Some scientists said that tiny particles don't "decide" what they are doing until someone measures them. Schrödinger thought that idea sounded weird. So in 1935, he imagined a cat in a box to show how strange it would be if those rules applied to big, everyday things. His friend Albert Einstein loved the idea!
No real cat was ever put in a box! It was a thought experiment: an experiment you do only in your imagination.
Words to Know
Tap each card to flip it.
Word match
Choose the word that matches each meaning.
Try It: Turn and Teach
Quick check
The Experiment
Schrödinger's thought experiment, in four parts.
A note about the real version
In Schrödinger's original thought experiment, the bottle held poison instead of sleepy gas, which is why people often say the cat is "alive and dead." We're using a gentler sleepy version here. Remember: no real cat was ever used. The cat only ever existed in Schrödinger's imagination.
Probability lab: open the box 20 times
The atom has a 50/50 chance: like flipping a coin. Before you start, predict: if you open the box 20 times, how many times will the cat be awake?
0 of 20 openings
Spinning coin: a helpful comparison
While a coin spins in the air, is it heads or tails? Some people say a spinning coin is a little like superposition: it only "lands" on one side when it stops. (It's not a perfect comparison, since a real coin always has one side up, but it helps us imagine the idea!)
Watch the video
Schrödinger's cat: A thought experiment in quantum mechanics, by Chad Orzel (TED-Ed).
Video not showing? Open it on YouTube.
Put the experiment in order
Check your understanding
The Cat Box
Click the box to find out if Schrödinger's cat is okay!
What's inside?
There are 24 different cats hiding in this box. Every time you open it, a different one might pop out. Can you find them all?
Cats found: 0 of 24
Big Questions
Let's think about it.
Philosophy isn't about finding the one "right" answer. It's about thinking carefully and being able to explain why you think what you think. Even the smartest scientists in the world still disagree about this one!
Writing Task: Type your response to each question. Write at least 2 sentences for each. You may be asked to share your responses. We will discuss this as a class.
Activities
Show what you know.
1. Thought experiment or real experiment?
A real experiment is done with real materials. A thought experiment happens only in your imagination. Sort each one.
2. Cave or Cat?
Does each idea fit Plato's Allegory of the Cave, Schrödinger's Cat, or both?
3. The Cat's Diary
Write a diary entry from the cat's point of view, sitting in the closed box, waiting for someone to open it. How does it feel to be "both" things at once? What happens when the lid finally opens?
4. Class Debate: What is the cat before we look?
Discuss with a classmate, then pick a side. Be ready to explain your reasoning in our class discussion.
Choose the ideas that support your side:
5. Design Your Own Thought Experiment
Now it's your turn to be a philosopher-scientist! Invent an imaginary experiment that makes people think about a big question.
Reflection
Wrapping Up: Final Response
Write a thoughtful response that answers the questions below. Do not simply answer each question separately. Connect your ideas into one strong piece of writing.
Your response should:
Push Your Thinking
My final response
Writing Expectations
Turn it in with Google Docs
This puts everything you wrote in this unit into a Google Doc: your Big Questions, diary, debate, thought experiment, and final response.