Chapter Menu Lesson 1: What is light? Lesson 2: Light and Matter Lesson 3: Using Lenses Lesson 4: The Eye and Vision Click on a hyperlink to view the corresponding lesson.

11.1 What is light? wavelength frequency medium electromagnetic spectrum

Light Transfers Energy 11.1 What is light? Light Transfers Energy Similar to water waves, light waves also carry energy from place to place.

11.1 What is light? Parts of a Wave The distance between any two crests of any two troughs is the wavelength.

Frequency and Wavelength 11.1 What is light? Frequency and Wavelength The frequency of a wave is the number of wavelengths that pass a given point in one second. As the frequency of a wave increases, wavelength decreases.

Electromagnetic Waves 11.1 What is light? Electromagnetic Waves The substance through which a wave moves is called the medium. Light is an electromagnetic wave, which is a type of wave that can travel in empty space as well as in matter.

11.1 What is light? A Range of Wavelengths The electromagnetic spectrum includes all electromagnetic waves. It is arranged in order, from those with the longest wavelengths to those with the shortest wavelengths. Frequency increases as wavelength decreases, and is arranged in order of increasing frequency.

11.1 What is light? Visible Light The visible light spectrum is the range of electromagnetic waves human eyes can detect. Visible light wavelengths are measured in nanometers (nm). The wavelengths range from 700 nm to 400 nm.

11.1 What is light? Visible Light (cont.)

What is the amplitude of a wave? A distance from crest to crest 11.1 What is light? A B C D What is the amplitude of a wave? A distance from crest to crest B distance from crest to trough C distance from crest to resting position D wavelength x frequency Lesson 1 Review

A the distance from crest to trough 11.1 What is light? A B C D What is a wavelength? A the distance from crest to trough B the distance from crest to the rest position C the distance from crest to crest D the opposite of frequency Lesson 1 Review

What is the term for the substance through which a wave moves? 11.1 What is light? A B C D What is the term for the substance through which a wave moves? A medium B substrate C water D vacuum Lesson 1 Review

End of Lesson 1

11.2 Light and Matter absorption transmission scattering refraction law of reflection

The Interaction of Light and Matter When light rays hit matter, they can be absorbed, reflected, or pass through the matter. All electromagnetic waves, including light, transfer energy from one place to another.

11.2 Light and Matter Absorption of Light Absorption occurs when light rays hit a material, and some of the rays’ energy is transferred to the atoms in the material. The transfer of energy can cause the temperature of the material to increase.

11.2 Light and Matter Transmission of Light Transmission occurs when light waves strike a material and pass through it, such as with glass. Whether the light waves are transmitted or absorbed depends on the wavelength of the light waves.

11.2 Light and Matter Scattering of Light Scattering occurs when a material causes light waves traveling in one direction to travel in all directions.

Opaque, Transparent, and Translucent Materials 11.2 Light and Matter Opaque, Transparent, and Translucent Materials The three candleholders are made of different materials that absorb, transmit, and scatter light in different ways.

The Speed of Light in Different Materials 11.2 Light and Matter The Speed of Light in Different Materials No object or wave can move faster than the speed of light in empty space. When light waves travel in matter, they move more slowly.

11.2 Light and Matter Refraction Refraction occurs when a light ray changes direction when it moves from one material to another.

Refraction and Speed Changes 11.2 Light and Matter Refraction and Speed Changes Light waves change direction—refract—when they change speed moving from one medium to another. Bending Light

11.2 Light and Matter The Visible Spectrum White light is a combination of all light waves in the visible light spectrum. Almost any color of light can be made by mixing the three primary colors—red, green, and blue—in different amounts.

The Visible Spectrum (cont.) 11.2 Light and Matter 11.2 Light and Matter The Visible Spectrum (cont.)

11.2 Light and Matter Reflection According to the law of reflection, when a light ray is reflected from a surface, the angle of incidence equals the angle of reflection.

Regular and Diffuse Reflection 11.2 Light and Matter Regular and Diffuse Reflection Light ray reflected from an uneven surface hits a spot in the surface that is at a slightly different angle, causing the rays to go in many different directions. Diffuse reflection is the reflection of light rays from a rough surface.

Regular and Diffuse Reflection (cont.) 11.2 Light and Matter Regular and Diffuse Reflection (cont.) The smooth surface of a mirror reflects parallel light rays so that they remain parallel. This is called regular reflection.

11.2 Light and Matter Reflection and Color As white light strikes and object, some of the light is absorbed and some is reflected. The reflected light enters your eyes and causes you to see the object. Color

11.2 Light and Matter A B C D What is the term for the process of transferring light energy to the molecules in a material? A transmission B absorption C scattering D refraction Lesson 2 Review

Which of the following does light travel fastest through? 11.2 Light and Matter A B C D Which of the following does light travel fastest through? A transparent objects B empty space C air D water Lesson 2 Review

Why does an object appear to be blue? A it absorbs the blue wavelength 11.2 Light and Matter A B C D Why does an object appear to be blue? A it absorbs the blue wavelength B it scatters the blue wavelength C it reflects all the other colors except blue D it absorbs all the wavelengths except blue Lesson 2 Review

End of Lesson 2

11.3 Using Lenses lens convex lens focal point focal length

11.3 Using Lenses What is a convex lens? A lens is a transparent object with at least one curved side that causes light waves to bend. A convex lens is a lens that bulges outward. Convex lens: parallel light rays are bent so they come together, or converge Concave lens: parallel light rays spread apart, or diverge

What is a convex lens? (cont.) 11.3 Using Lenses What is a convex lens? (cont.) A concave lens is thinner in the middle than at the edges.

Light’s Path Through a Convex Lens 11.3 Using Lenses Light’s Path Through a Convex Lens A light ray bends when it slows down moving from air into the lens. The light ray bends again when it speeds up moving from the lens back into the air.

Focal Point and Focal Length 11.3 Using Lenses Focal Point and Focal Length The focal point is the point where all of the beams of light converge. In a convex lens, all light rays traveling parallel to the optical axis are bent so that they pass through the focal point.

Focal Point and Focal Length (cont.) 11.3 Using Lenses Focal Point and Focal Length (cont.) The focal length is the distance from the center of the lens to the focal points.

Image Formation by a Convex Lens 11.3 Using Lenses Image Formation by a Convex Lens The image formed by a convex lens depends on the position of an object relative to the focal point.

11.3 Using Lenses Optical Instruments An optical instrument uses lenses to focus light and create useful images. Different optical instruments do this by combining lenses in various ways. Types of optical instruments Cameras Telescopes Microscopes

11.3 Using Lenses Cameras A camera is focused by moving various lenses back and forth until a sharp image is formed. The image is smaller than the object and is upside down. To take a picture, the shutter opens so that light enters the camera, and film or an electronic sensor is exposed.

11.3 Using Lenses Cameras (cont.) To control the amount of light that reaches the film or light sensor, cameras have a diaphragm or an aperture.

11.3 Using Lenses Telescopes As an object gets farther away, less of the light from the object enters the openings in your eyes. A telescope is an optical instrument that makes far-away objects seem closer. There are two basic types of telescopes—refracting and reflecting.

Refracting Telescopes 11.3 Using Lenses Refracting Telescopes The objective lens in a refracting telescope is much larger than the opening in a human eye. Much more light from a distant object enters the objective lens than would enter an eye.

Reflecting Telescopes 11.3 Using Lenses Reflecting Telescopes An image of a distant object is formed inside the telescope tube when light rays are reflected from the curved surface of a mirror. The largest telescopes are reflecting telescopes.

11.3 Using Lenses Microscopes The eyepiece lens of a microscope is positioned so it is closer to the image than one focal length. This makes the image enlarged by the objective lens even larger.

C two focal lengths from the lens D in the center of the lens 11.3 Using Lenses A B C D Where do all the beams of light passing through a convex lens converge? A focal point B optical axis C two focal lengths from the lens D in the center of the lens Lesson 3 Review

What happens to light when it moves from air into a convex lens? 11.3 Using Lenses A B C D What happens to light when it moves from air into a convex lens? A it is reflected B it is scattered C it slows down D it speeds up Lesson 3 Review

A refracting telescope B reflecting telescope C camera D microscope 11.3 Using Lenses A B C D Which uses a curved mirror to form an image that is magnified by an eyepiece lens? A refracting telescope B reflecting telescope C camera D microscope Lesson 3 Review

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