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On page 2 of the lesson, click 'Shifting Light Spectra Lab Activity.' The activity will come up with a page that says 'Space: The Final Frontier." Read and click 'continue.' Read the next page and click 'continue.' After reading the third page, click 'Shifting Light Spectra.' That should bring you to a page called 'Welcome to Shifting Light Spectra.' Once there, read the page and then click 'Learn More.' This will bring you to a page with a picture of a galaxy on it. This is where you will get your answer to question 1. Slide this slider from its position at 'Stationary' to 'Farther,' and observe how the spectral lines in the bottom spectrum change. Then slide it to 'Closer' and observe the lines again. Answer question 1 on your worksheet. You don't need to put anything on question 2. It will be answered in the data table on the next page.
After doing this, the button 'Explore Further' should become available on the picture. Click it, and you will come to a page with a picture of four galaxies (they look like stars in the picture). Click the first galaxy, and you'll see two spectrums. The top one is the galaxy's spectrum from the past, and the bottom one is its spectrum from the present. Look at the lines on the spectrums, and see what kind of shift it has—are the lines shifting toward the blue end, or toward the red end? After choosing your answer click 'submit.' Repeat this process for all four of the galaxies in the picture, and use the information to fill out the data table on page 2. Just mark whether each galaxy is redshifted or blueshifted, and whether that indicates an expanding universe or a shrinking universe. Then you can answer question 4—tell me how many galaxies are redshifted compared to how many are blueshifted. For question 5, tell me whether you think most of those galaxies were closer to us or farther away from us 100 million years ago.
Once all 4 galaxies have been done, a 'Continue' button will appear under the picture. When you click it one last page will come up. Answer the question there and click 'submit.' The lab is then complete. To finish the worksheet answer question 6, and finally fill out the 'Draw Conclusions' section.