Astronomy Laboratory Manual - Hartnell College

AST 1L

Lab Module 6

Converging Lenses Inquiry

Objectives

To introduce the inquiry process and investigate a physical phenomenon in a way that simulates how scientific research is conducted. To discover how converging lenses work and apply this knowledge to the functionality of simple refracting telescopes.

Background: What is Inquiry?

Unlike typical labs, which tend to be guided, step-by-step recipes, inquiry is modeled on how scientists actually perform their research, with no one to tell them what to investigate or how to carry out their investigations. Inquiry can be challenging, but it can also be rewarding. You will become the resident expert on your topic of interest and will share what you learned with your classmates in much the same way scientists do with their colleagues. Inquiry involves making observations, developing questions, designing experiments, making and testing predictions, recording results, and reflecting on, summarizing and communicating your understanding. Facilitators will be available to help you throughout the activity. They can help you determine what to investigate, provide advice on methods for setting up your investigation, and provide general support and feedback. They are not teachers, however, and will not give you the answer. At the end of this inquiry activity, the facilitators will summarize your findings and tie them together in what is known as a final synthesis.

Your facilitators will begin by showing you some phenomena involving converging lenses. From what you observe, you will determine which phenomenon you would like to investigate. Your goal in this activity is to understand this phenomenon and be able to explain it to the rest of the class using visual aids where appropriate.

A good way to formulate your explanation is as follows:

  1. What is your claim? That is, what did you learn?

A claim is statement about the underlying principle(s) responsible for the phenomenon you observed.

  1. What evidence do you have to back up your claim?

Evidence can be any observations, data, or information you gathered during your investigation that helped lead you to make your claim.

  1. What is your reasoning? How does the evidence support your claim?

Your reasoning is a logical argument for how you interpret your data or observations to justify your claim.

Inquiry is often challenging, especially the first couple times you experience it. It is natural for you to struggle. If you get stuck at any point during your investigation (this will probablyhappen):

  1. Don’t get discouraged!
  2. Try drawing a picture.
  3. Try having each group member explain what they think the problem is to the rest of the group in their own words.
  4. Then, find your facilitator.

Opening Discussion

In this activity we will be learning about converging lenses, which can be used to make astronomical telescopes. Astronomers use telescopes to observe distant, faint objects like galaxies, stars, and planets. Please use the space below to take notes on the class discussion of telescopes.

Have you seen or heard about any telescopes? What are some words you would use to describe their components or what they do to images/ light?

Starters

Lenses do not have to be made of glass, and they have many other applications besides being used in telescopes. At your workstation, you have a few examples of common lenses, or objects that can be used as lenses. Your facilitators will demonstrate some properties of lenses, and then you will have time to experiment for yourself.

  1. What are some words that you have heard used to describe these lenses? How would you describe some of the effects you observe as you play with the lenses in front of you? Write down any vocabulary that come to mind, and discuss with your neighbors a few items that you could share with the class. Add to this list once we discuss them as a group.
  1. Write down any questions that you may have about how lenses work. You may want to use some of the vocabulary from #1 above in formulating your questions. Add to this list after we discuss them as a group.

Investigation

Now that we have observed some properties of lenses and discussed various ways in which lenses can be used, you will select a question about how lenses work that interests you and begin your investigation.

  1. What question or aspect of lenses are you focusing your investigation on?

______

  1. Is this a property of the lens itself (some feature of the lens that cannot be changed), or how the lens is used (the phenomenon seems to have something to do with how you position the lens), or possibly both?

______

As you go through your investigation, use the space provided below to describe your thought process and techniques you are using (examples of this include, but are not limited to: equipment used, variables, diagrams, calculations, graphs, etc.). Feel free to attach extra pages, if necessary.

  1. With respect to your area of investigation, what were your findings? (Also, if you changed what you were originally investigating, what did it change to?) Make sure to also explain the steps you took to reach your conclusions. Your response here should reflect very closely what you are presenting to the class. You may find it useful to follow the claim-evidence-reasoning formulation described in the introduction. Feel free to attach extra pages, if necessary.

Claim:

Evidence:

Reasoning:

What else did you learn?

Please use this space to write down a few things that you learned from your classmates’ investigations and from the facilitators’ synthesis.

Building a Telescope

Now that you have investigated the properties of converging lenses, you will have a chance to build your own telescope. Your facilitators will provide a handout to guide you. Please attach your completed telescope worksheet to this page.

Activity Feedback

Do you have any comments/ thoughts on how this activity went? Any suggestions for how we could improve it in the future?

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Lab Module 6: Converging Lens