Perception lesson 2

Empiricism All knowledge is ultimately based on perceptual experience

The subjects you study? Can you list the role perception plays in your different IB subjects? Are there any areas of knowledge where perception plays NO role?

Common-sense realism Perception is passive and gives us an accurate picture of reality Do you think our senses give us an accurate picture of how the world really is?

illusions.com/opticalillusions/impossible_motion/

Perception is a complex process Sensation and interpretation

Interpretation: Context

Interpretation: Expectations

The following four slides will be shown very quickly. Try to remember what the four cards are.

Can you name them?

Illusions from other senses? Can you think of any illusions from our other senses? YouTube - Endless Kaleidocycle and Ever-Rising ScaleYouTube - Endless Kaleidocycle and Ever-Rising Scale

Perceptual illusions Pass the two blocks around. Which one is colder? Put ice cubes on the blocks and watch

Perceptual illusions How did your sense of touch score?!

Extension of the senses

Electromagnetic spectrum

Visible light

λ ≈ 700 nmλ ≈ 420 nm

Ultraviolet waves λ ≈ nm

Ultraviolet waves λ ≈ nmλ ≈ 10 – 100 nm

X-rays λ ≈ nm λ ≈ 10 – 100 nm

X-rays λ ≈ nm λ ≈ 10 – 100 nm λ ≈ 1 – 0.01 nm

Gamma rays λ ≈ nm λ ≈ 10 – 100 nm λ ≈ 1 – 0.01 nm

Gamma rays λ ≈ nm λ ≈ 10 – 100 nm λ ≈ 1 – 0.01 nm λ ≈ – nm

Infrared waves λ ≈ nm λ ≈ 10 – 100 nm λ ≈ 1 – 0.01 nm λ ≈ – nm

Infrared waves λ ≈ nm λ ≈ 10 – 100 nm λ ≈ 1 – 0.01 nm λ ≈ – nm λ ≈ 0.1 to 0.001mm

Microwaves λ ≈ nm λ ≈ 10 – 100 nm λ ≈ 1 – 0.01 nm λ ≈ m λ ≈ 0.1 to 0.001mm

Microwaves λ ≈ nm λ ≈ 10 – 100 nm λ ≈ 1 – 0.01 nm λ ≈ m λ ≈ m λ ≈ 1 to 0.1 cm

Radio waves λ ≈ nm λ ≈ 10 – 100 nm λ ≈ 1 – 0.01 nm λ ≈ m λ ≈ m λ ≈ 1 to 0.1 cm

Radio waves λ ≈ nm λ ≈ 10 – 100 nm λ ≈ 1 – 0.01 nm λ ≈ m λ ≈ m λ ≈ 1 to 0.1 cm λ ≈ m

Electromagnetic spectrum λ ≈ nm λ ≈ 10 – 100 nm λ ≈ 1 – 0.01 nm λ ≈ m λ ≈ m λ ≈ m λ ≈ m

Electromagnetic spectrum Long Wavelength Short Wavelength

Ultrasound

What is really out there?

Does the “sweetness” exist in the coke or only in your brain?

What is really out there? Where is the green in the grass? In the grass or in your brain? If we had evolved differently, sensitive to electromagnetic radiation of different frequencies we would not see grass as green at all…….in conclusion the world really has no colour at all!

What really is out there? If a tree falls in a forest, and nobody is there to hear it, does it make a sound?

Two types of sound? Physical – vibrations in the air Experienced – the sound we hear/experience in our brains

No experienced sound before life on earth?

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