Bell Work #1 Tuesday, 11-21-17 How do you see objects? Light enters the eye Light focuses on the retina An image forms A signal goes to the brain Let’s look back at yesterday! Trace the path of light.

Monday, 11-20-17 Unit 4 – Wave Behaviors and EM Waves Chapter 4 – Light Lesson 5 – Using Light SCCCR Standard 8.P.3: The student will demonstrate an understanding of the properties and behaviors of waves. Learning Objective 8.P.3A.6: Students will obtain and communicate information about how various instruments are used to extend human senses by transmitting and detecting waves (such as radio, television, cell phones, and wireless computer networks) to exemplify how technological advancements and designs meet human needs.

How do cameras, telescopes, and microscopes work? Essential Question How do cameras, telescopes, and microscopes work? Camera- the lenses in a camera focus the light to form a real, upside down image in the back of the camera. Telescope- telescopes use lenses or mirrors to collect and focus light from distant objects Microscopes- microscope use a combination of lenses to produce and magnify an image

F-numbers, on page 140, tell the size of the lens opening. Cameras F-numbers, on page 140, tell the size of the lens opening. How does the “light-gathering ability” change as the f-number increases? The larger the number, the smaller the opening and the less light is let in. If you wanted a picture in very low light, what f-number would you choose? Why? 1.0, because it lets in the most light. If you wanted a picture on a sunny day, what f-number would you choose? Why? 5.6, because less light is needed for a good picture.

A telescope that uses convex lenses to gather and focus light Vocabulary (Page 141) Camera An optical instrument that uses lenses to focus light, and and film or an electronic sensor to record an object’s image Telescope An optical instrument that forms enlarged images of distant objects; Examples - Ships in the ocean, Stars in the sky… Refracting telescope A telescope that uses convex lenses to gather and focus light Reflecting telescope a telescope that uses a curved mirror to collect and focus light

Vocabulary (Page 141) Objective Eyepiece Microscope A lens that gathers light from an object and forms a real image Eyepiece A lens that magnifies the image formed by the objective Microscope An instrument that makes small objects look larger

Are the images that a camera forms real or virtual? How do you know? Camera lenses focus light to form an image on film or a sensor in the back of the camera. Are the images that a camera forms real or virtual? How do you know? Real; the images can be projected and are upside down How does the camera adjust the focus of the image? By moving the position of the lens How does the camera adjust the amount of light that enters the camera? By adjusting the size of the opening and the amount of time it is open Look at “APPLY IT” on page 141

Telescopes (Figure 1 on page 142) What is the difference between the terms reflect and refract? “Reflect” means to bounce back. “Refract” means to bend while passing through. Would you expect a reflecting telescope to use mirrors or lenses to gather light? Mirrors Would you expect a refracting telescope to use mirrors or lenses to gather light? Lenses

Telescopes (Figure 1 on page 142) Label the telescopes in figure 1. What structure is found in both telescopes? The convex lens of the eyepiece What is the function of the convex lens in a reflecting telescope? To focus the image from the mirrors

The image is larger or magnified Microscopes Like a refracting telescope, microscopes use lenses to produce an image. How does the size of the image produced by a microscope compare to the size of the specimen being viewed? The image is larger or magnified Does a microscope use the same light source as a telescope? No; a microscope has its own internal light source. Exit Slip “Assess Your Understanding” (Page 143, 1a and 1b)