Can I Believe My Eyes?

Can I Believe My Eyes?

Eyes are 1 of 5 Senses that Send Information to Brain for Storage or Memory

The Electromagnetic Spectrum

The electromagnetic spectrum covers electromagnetic waves with frequencies ranging from below one hertz to above 10 25 hertz, corresponding to wavelengths from thousands of kilometers down to a fraction of the size of an atomic nucleus.

Diagram of the Human Eye

The human eye can only detect the visible light wavelengths of the EMS. Light enters the pupil, hits the lens, lens focuses it on retina, retina transmits it to optic nerve, optic nerve sends signal to brain, and brain makes sense of it.

Light & Sound travel by wavelength

This is an example of a wavelength. Our eyes detect the different wavelengths as different colors.

Different Wavelength = Different Color

Red wavelengths are longer and have less energy compared to violet and blue which are shorter and have more energy.

Color results from Reflection:

Black absorbs all

White reflects all

The color that is NOT absorbed is reflected toward your eye.

Why we see Green?

Other wavelengths absorbed

Green is reflected to our eyes.

Multiple Choice

Use what you know--Fill two beakers w/water. Add food coloring to one beaker. Shine a flashlight on both beakers. Predict which will warm more.

• Both beakers will warm the same.

• The beaker with food coloring will warm more.

• The beaker w/o food coloring will warm more.

• Neither beaker will warm.

How Does a Mirror Work?

A smooth surface reflects light in a uniform manner and allows one to see their image in a mirror. Scattering is what happens when light bounces off surfaces that are not smooth.

Multiple Choice

Using what you know about reflection, answer the following question: Why can one see their reflection in a mirror?

• None of the light rays bounce back to your eye that's why you can see your reflection.

• All of the light rays are reflected from a mirror so they bounce back to your eyes allowing you to see your reflection.

• Mirrors are opaque that's why you see your reflection.

• Mirrors do NOT have a smooth surface that's why you can see your reflection.

Refraction

• Bending of Light

• Refraction varies by Wavelength

Refraction varies by Wavelength

• The reason the straw in the above picture appears bent is due to refraction.

• A different color straw would bend the light differently.

Open Ended

Design a simple experiment to see how refraction differs according to wavelength/color.