Visible Spectrum and Energy Concepts

Duane Friend from the University of Illinois Extension explains how the sun generates energy that travels in waves. These waves vary in wavelength, with shorter wavelengths being more powerful. The sun emits many short wavelengths, including ultraviolet energy, which is absorbed by Earth's atmosphere. Humans can only see a small portion of this energy, known as the visible spectrum, ranging from 380 to 700 nanometers. Different wavelengths appear as different colors, with red being the longest visible wavelength. Energy emitted back to space is in longer wavelengths, invisible to humans but visible to some animals like spiders and reptiles.

What is the primary way energy from the sun travels through space?

• In waves

• In beams

• In particles

• In rays

How does the wavelength of energy relate to its power?

• Shorter wavelengths are more powerful

• Shorter wavelengths are less powerful

• Wavelength does not affect power

• Longer wavelengths are more powerful

What is the range of wavelengths that humans can see?

• 700 to 1000 nanometers

• 100 to 300 nanometers

• 380 to 700 nanometers

• 500 to 800 nanometers

Which color in the visible spectrum has the shortest wavelength?

• Violet

• Green

• Red

• Yellow

Which color in the visible spectrum has the longest wavelength?

• Blue

• Violet

• Red

• Green

What is a nanometer?

• 1 millionth of a meter

• 1 hundredth of a meter

• 1 billionth of a meter

• 1 thousandth of a meter

What type of energy does the Earth send back to space?

• Shorter wavelengths

• Visible wavelengths

• Ultraviolet wavelengths

• Longer wavelengths

Which creatures are believed to see ultraviolet energy?

• Spiders

• Birds

• Fish

• Mammals

Which creatures can see infrared energy?

• Reptiles

• Birds

• Insects

• Amphibians