Alberta Grade 8 Science – Light and Optical Systems Practice Test

Visible light is the part of the electromagnetic spectrum that humans can detect with our eyes, covering wavelengths roughly from 380 to 750 nanometers. This range is why we see the world in color—the different wavelengths correspond to different perceived colors. Light in this range comes from many sources, not just LEDs; the Sun and everyday light bulbs also emit visible light. Whether light passes through a material depends on that material’s properties: some are transparent and let visible light through (like air and glass), others are opaque and absorb or reflect it. The idea that visible light is blocked by most materials isn’t accurate because many common substances do transmit or only partially block certain wavelengths. And yes, visible light travels easily through air, which is why we can see things far away and why daylight reaches us from the Sun.