Welcome Assignment August 9 & 10, 2011 Planner: Wear covered shoes for rest of week Type up lab report as the information comes Get Science Notebook: The Universe 1. Make a circle map – brainstorm all the things you can think of in the universe (space). 2. In your lab group categorize the items you put down into a KWL Chart.

K – What you know W – What you want to know L – What you learned

How do scientist know what’s out there? Write some questions you have about the universe. KWL Complete the W part of the KWL Chart. K – What you know W – What you want to know L – What you learned

Welcome Assignment: Get Science Notebook – Write title: How Far is that Star? WEAR Covered Shoes August 10 – 12 TYPED Lab Report due August 17 = Period 1 TYPED Lab Report due August 18 = Period 2, 4, 5, 6

Science Investigation: Research Question/Purpose Background Information/Equations Hypothesis Materials Procedure Data/Observations Data Analysis & Calculations Conclusion

Research Question/Purpose How can parallax be used to determine distances from earth to nearby stars? Skills Measure distances between two points Calculate the distance to an object using ratios of measured values; Compare the calculated value to the measured value; Predict the parallax of an object at different distances.

Background Information/Equations Write from your past experience: What do you notice when you view a fast moving object up close, and a fast moving object from far away? (think about an airplane in the sky) Distance = Diameter X Focal Length Parallax Shift

Hypothesis If…Then…Because….

Materials Masking tape Black and red pencils Extension cord Lamp, 100 watt Lightbulb Copier Paper Box (no lid) Flat Table Paper Clips Metric Ruler Meter Stick Pen Paper Calculator

Procedure – Part 1 1. Place the lamp on a table in the middle of the classroom 2. Make a small hole in the middle of the box 3. Place the box on a flat table so the hole points toward the light 4. Line the left side of the box with the table 5. Put a small piece of tape on the table below the hole. Use the pen to make a mark on the tape directly below the hole.

Procedure - Part 2 6. Label sheet of copy paper “Star 1” 7. Place it inside the box 8. Turn off the classroom lights and turn on the lamp 9. RED Pen – Mark the paper where you see a dot of light. 10. Move the box so the right edge of the box lines up with the right edge of the table 11. Put another small piece of tape under the new location of the hole, and make a mark to record the specific position (telescope 6 months later) 12. Regular Pencil – mark the second dot B. Dot B represents the image of the star as seen 6 months later from the other side of Earth’s orbit. 13. Remove the paper.

Measurements 14. Measure and record the distance in millimeters between dots A and B. This distance represents the parallax shift for Star Measure and record the distance from the hole (lens) to the paper (film) at the back of the box in millimeters. This distance represents the focal length of our telescope. 16. Measure and record the distance in millimeters between the marks on the two pieces of masking tape. This distance represents the diameter of Earth’s orbit. 17. Use a meter stick to measure the actual distance from the box to the bulb. How did your calculations for Star compare with the actual distance

Data/Observations StarParallax Shift (mm) Focal Length (mm) Diameter of orbit (mm) Calculate d Distance to Star (mm) Calculate d Distance to Star (m) Actual Distance to Star (m)

Data Analysis & Calculations Use the following formula to calculate the distance from the telescope to Star 1. Distance = Diameter X Focal Length Parallax Shift What happened to the dot of light for each star when you moved to your model telescope from one side of Earth’s orbit to the other? What caused the apparent change in position of the dots of light for each star? Explain.

Conclusion Is the parallax shift greater or smaller the farther away the star is? Relate each star’s parallax shift to its distance from Earth. Use data to support your statement. Validate or Refute your Hypothesis. Use data to support your statement. Identify any errors in calculations, measurement, etc. Think about your experience (fast moving objects) explain how it relates to this lab? How can parallax be used to determine distances from earth to nearby stars? Explain how this method works. Would this method work for objects very close? Would this method work for objects very far? Would this method work for all objects in the universe?