Lesson 8 of 8 · Thermodynamics
Experiment⭐ 30 XPEntropy and the Direction of Change
Thermodynamics.
🎯 Your mission
Predict it first. Then prove yourself right (or wrong).
⚡ The twist
Nature loves to surprise the careful watcher.
Mind = Blown
🔬 The more you look, the more nature shows you.
Make a hypothesis first
Before you start: write down what you think will happen, and why.
What You'll Learn
Energy spontaneously spreads out. The second law says total entropy — a measure of how dispersed energy is — never decreases in a closed system. That is why a hot drink cools to room temperature but a room-temperature drink never spontaneously heats up.
Key Words
Tap a word to see its definition.
Materials Needed
- ink or food colouring
- clear glass of still water
- phone camera
Safety First
- Food colouring stains — protect the work surface and clothing.
Steps
Read the explanation above and note the two key terms before you start.
Place a drop of ink in still water and photograph it every 30 s for ten minutes. Describe the sequence, then explain why the reverse film would look obviously wrong even though it breaks no conservation law.
Record what actually happened, including anything that did not match what you expected.
Write a conclusion that answers the question this lesson opened with, and state your uncertainty.
Check Your Understanding
Question 1
1 of 2The second law of thermodynamics says entropy in a closed system:
Where you see this in real life
This shows up in your everyday life more than you'd think.
Stretch Challenge
Try this in real life this week.
Try one experiment in real life this week — even a tiny one.
For the dinner table
“What's the most surprising thing you learned today?”
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Entropy and the Direction of Change
Predict it first. Then prove yourself right (or wrong).
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