AOSC Light and Telescopes

Table of Content

Design Team Meetings
Activity Overview
Background
Design Goals & Evidence
Content Synthesis Goals
Activity Timeline
Facilitation
Pinhole boxes starter
Lenses Starter
Mirror starter
Application/Challenge
Materials List

AOSC Twiki

Design Team Meetings

Next Meeting

Wednesday May 21, 11 a.m. HST (2 p.m. PDT)

Agenda

Develop detailed schedule and facilitation plan for inquiry (using Inquiry Activity Prep Checklist)

Action Items

Write detailed description of starter/application and specific materials needed on wiki:

-Mike: Lenses starter

-Nino: Mirrors starter

-Emily: Pinhole starter

-Greg: Telescope design application

Provide feedback for starters and application once they are outlined on the wiki

* Practice starters, practice with investigation materials, explore likely questions and investigations

Benchmarks

April 15: Share draft outlines of starters and application
April 29: complete list of supplies that need to be ordered, and draft list of what we think the CfAO has that we need
May 13: complete list of supplies that need to be shipped from CfAO or purchased in Hawaii
Week of May 26: Test run of starters/investigations/application in Hawaii (with 2 or more people if possible)

Previous meetings

March 16 & 17 (SLT workshop)

April 2

Assign responsibilities for inquiry design
Set benchmarks (goal and date) for design
Determine participation in the rest of the short course

April 15

Review availability and travel plans for beginning of short course and to plan testing and set-up (late May)
Share drafts of starters
Begin developing materials list

April 29

Continue refining materials list and plans for starters

Friday, May 2, 9:30 a.m. HST (12:30 p.m. PDT)

Finalize materials list so new supplies can be ordered through CfAO

Wednesday May 14, 11 a.m. HST (2 p.m. PDT)

Go over Inquiry Activity Prep Checklist in order to identify and plan remaining preparation

Activity Overview

The Light & Telescopes Inquiry is a two-day activity in which students investigate light and geometric optics principles using pinholes, lenses, and mirrors. The goal of the activity is to connect the principles of light and geometric optics to telescope design, motivate students to consider telescope design during the summit tour, and have students develop a fundamental understanding of the telescopes at the observatories in which they will be interns.

Background

AOSC students are college STEM majors who will be interns at an observatory (or the IfA) during the summer.
Host observatories are: CFHT, SMA, Subaru, Keck, Gemini, and IfA-Hilo.
The majors of the interns are: computer science/math (3), mechanical engineering (3), physics/astronomy (3), civil engineering (1), electronics technology (1), and electrical engineering (3).
The inquiry will begin on Monday afternoon of the week-long short course, after ice-breakers, introduction to the CfAO and internships, introduction to the communication curriculum (Lynne), and an introduction to astronomy.

Design Goals & Evidence

Goals

Students plan and implement an investigation of image creation using various optical elements and explain their observations using geometric optical principles.
Students can predict and test how the path of light is changed by lenses, mirrors, and pinholes and where images are created in systems with multiple optical elements.
Students can use principles of geometric optics to explain a complex optical system.
Students understand that light travels in a straight line and can use this to explain how optical elements change the path of light and how images are created.
Students think critically and identify aspects of observed phenomena that are relevant to scientific explanation.

Evidence

Students can describe their experimental set-up and investigation to other students and represent it in drawings.
Students can answer "what if...?" questions from facilitators.
Students can "fill in" a ray-tracing diagram of multiple telescope designs.
Students can draw ray-tracing diagrams for optical elements and optical systems and determine where images are created.
Students generate questions that can be used to motivate inquiry investigations and develop scientific explanations.

Content Synthesis Goals

(Any goals that are wanted to lead into the telescope design activity?)
Content-specific goals that we should make sure are reflected in starters, investigations, content synthesis, and application/design challenge.

Something about light in a straight line
1. Light travels in straight lines, which can be represented by an arrow called a ray
Diffuse light is a collection of overlapping images of a source
Pin hole and showing the image of filament
1. A pinhole creates an image by blocking all but a small number of rays
Lenses and mirrors can be thought of as assemblies of individual pinholes; that is, each point on a lens or mirror creates an image
Lenses and mirrors create an image by bending light rays so that images overlap, and the more images that overlap (the larger the lens/mirror) the brighter the image

Activity Timeline

Day 1

(0:10) Introduction to Inquiry
(1:00) Starters: Three stations (pinhole boxes, lenses, mirrors) 20 minutes each
1. (0:05) Demonstration
2. (0:05) Students experiment with equipment
3. (0:08) Students write questions on sentence strips (and continue experimenting with equipment)
4. (0:02) Rotate to the next station
(1:30) Lunch break (with mentors); facilitators sort questions and prepare gallery walk
(0:20) Gallery walk, pick question to investigate, and form groups
1. (0:03) Mike introduces gallery walk and reminds students about aspects of investigation (from introduction)
2. (0:10) Students read questions and begin to form groups
3. (0:07) Instructors intervene to assist in group formation
(3:00) Investigations
1. (0:45) Make sure groups have begum active investigation (not just planning)
2. (1:15) Thinking Tool (Emily)
3. (0:30) Groups begin to wrap up and plan continuation of investigation for tomorrow (1 hour)
Facilitator Check-in before (or after) dinner

Day 2

(1:00) Complete investigations
(0:30) Prepare presentations (+break)
(0:40) Split sharing out
(0:10) Content Synthesis - Mike's Version
(0:10) Break
(1:00) Telescope design application/challenge
1. (0:05) Introduction to challenge
2. (0:30) Group work on challenge
3. (0:15) Reflector and refractor groups compare/discuss results
4. (0:10) Entire group compares/discusses/summarizes results

Facilitation

Facilitators ask students to predict where an image will be created and how it will be different after introducing a new optical element to the system.
Facilitators ask students to explain their investigation (what, why, how) at multiple stages of the inquiry.
Facilitators ask students to apply their explanation to other optical systems (i.e.telescopes).

Pinhole boxes starter

Note: aspects that still need to be worked out are in bold
Preparation: make three or four pinhole boxes of various sizes (directions for a hand-held box, directions from AOSC 2007, pinhole tube, Exploratorium pinhole viewing tube) and with varying pinhole sizes.
If it is sunny, do starter outside. If it is not bright enough outside, have a large, bright, non-uniform light source inside.
First describe how the box was made: show students the screen inside and the pinhole opposite the screen. Emphasize lack of lenses and mirrors.
Have students wear/look through pinhole boxes at image on screen. Let students recognize up-down inverted image. Then have an instructor or student stand behind students looking through pinhole boxes. Direct instructor or student to wave left arm, then right arm (to show less-obvious side-to-side image inversion).
Let students take turns looking through different boxes and compare images created with different size boxes and pinholes.
Take a two-copy-paper-box-sized box with a larger pinhole (2-4 cm diameter) and have student(s) observe image. Hold a plastic lens (43mm diameter, 400mm focal length) over the pinhole, and have student(s) observe how the image changes.

Lenses Starter

Lens Starter Write Up - Post Inquiry

Working Assumptions:

5 students per / starter

3 groups working on questions

Each working group should have at least 2 lenses of each type

Material list assumes minimum quantities

Goals: (Mostly taken from AOSC 2007 starter list)

Show the students optics and ask them to inspect them (look through, feel, investigate shape).

Show that the light source, 1 lense, and a screen placed at the proper distances will create an image of the light source on the screen. Show that moving the screen will change image focus.

Show that blocking part of the light source will obscure part of the image (inversely - i.e., image inversion).

Show that blocking part of the lense will simply dim the image, but the image is still clear and the entire source is still imaged.

Show that including multiple lenses will create different images. Setup 1 concave and 1 convex lense and show how resultant image is affected. Setup two convex lenses and show how resulting image is affected.

Let them play with the materials and formulate questions.

Mirror starter

Demonstration:
- Red light bulb in power strip, black paper screen, and various concave spherical mirrors
- Two identical mirrors are pre-aligned, set up in clay, and covered with a folded index card
- Make image with curved mirror, then have students predict what the image will look like when half of the mirror is covered.
Procedure:
- Demonstrate making an image of the red filament on the paper screen (in and out of focus)
- Show students a smaller diameter mirror (with a longer focal length)
- Ask students where they think this mirror needs to be placed (relative to the previous, larger diameter mirror) to make an in-focus image on the screen
- Show students that the mirror needs to be further away from the screen
- Make an image with both mirrors at once and allow students to compare images
- Uncover two mirrors set in clay to reveal apparently single image
- Cover/uncover one mirror at a time from various directions and have students observe what happens to image
- Let students experiment with the variety of spherical mirrors and formulate questions
- Make image with curved mirror, then have students predict what the image will look like when half of the mirror is covered.
- Students look into flat, concave, and convex mirrors and make observations (bringing the mirrors in from arms length to the tip of their nose and notice how the images change). Students should explain what does happen to the image.
- Students use flexible concave/convex mirrors, and then transitioning to making images on screens with the mirrors
- (if necessary) Students make an image with a pinhole (.5 cm diameter) in front of a flat mirror. This would nicely combine pinholes and mirrors.

Materials Needed: flat mirrors, curved mirrors of various sizes and radii of curvature, red light bulb, black paper screen, clay or mirror holders, deformable mirrors

Possible Questions:
- How do the images compare (brightness, size, sharpness, inversion, etc.)?
- How can a non-inverted image be created?
- How do the image locations compare (focal length)?
- How can the image position be moved?
- What happens when half the mirror/lens is covered?
- In which cases is a real image formed?
- In which case is a virtual image formed?
- On which side of the mirror are real images formed?
- On which side of the mirror are virtual images formed?
- Are real images formed by converging or diverging rays?
- Are virtual images formed by converging or diverging rays?
- In which case(s) is the image smaller than the object?
- Which type of image (real or virtual) is upright?
- In which case is no image formed?