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Science and Technology, Class 8
The Radiation Method of Heat Transfer
No medium needed · Travels as waves · Colour matters
What We Will Learn Today
☀️
What radiation is and why it needs no medium
〰️
What a wave is and what it carries
🔊
The difference between mechanical and electromagnetic waves
🎨
How colour changes absorption and emission
🍵
How a thermos blocks all three methods
Think it through
How Did the Sun's Heat Arrive?
CONDUCTION
No matter joins the Sun to us, so this cannot be the answer.
CONVECTION
Heated air rises upward, it does not come down to us.
RADIATION
The heat still arrives, so it came with no medium at all.
Presenter notes: Today we find out how the Sun's heat crosses empty space to reach us.