1- Lesson overview

2- Pre-assessment

3- Think-Pare Share

4- Explore the Star Spectra

5- Investigate

6-Individual Work (Scientists)

6- Choice board

7- Practice

8- Exit Ticket

9-Reflection

10-Reflection

Learning Objectives:

1. Understand the concept of redshift and how it provides evidence for the expanding universe.

2. Explain the Doppler Effect and how it applies to both sound and light waves.

3. Identify spectral lines and use them to determine the elements present in stars and planets.

4. Apply knowledge of redshift and spectral lines to analyze astronomical data.

https://gizmos.explorelearning.com/find-gizmos/launch-gizmo?resourceId=558

1. What do you notice about the spacing of the sound waves in front of and behind the moving vehicle?

2. How does the frequency of the waves change when the vehicle moves faster?

3. What happens to the pitch of the sound as the vehicle approaches and then moves away?

4. Try changing the speed of the vehicle. How does this affect the Doppler shift?

5. What happens when the vehicle is stationary? How do the waves look?

2. Just like a siren sounds lower when it moves away, light from galaxies shifts to red. This is called redshift and shows galaxies are moving away.

1. Changing over time:

People or things change slowly, like how someone gets older or how seasons shift. You might notice small signs—like wrinkles, changing habits, or leaves turning color.

2. Sirens and galaxies:

When a siren moves away, it sounds lower because the sound waves stretch out. Light works the same way—when galaxies move away, their light shifts to red. This helps scientists know the universe is expanding.

Moving away = redder (redshift).

Moving closer = bluer (blueshift).

When a siren moves away, it sounds different because the sound stretches out and gets lower. That’s called the Doppler Effect.

Light does the same thing! When galaxies move away from us, their light stretches and turns more red. This is called redshift, and it shows us that the universe is getting bigger.

When a siren moves away, it sounds lower. Light works like that too—if a galaxy is moving away, its light looks more red. That’s how scientists know the universe is getting bigger.

When have you noticed things or people changing slowly over time? What signs did you see?

I’ve noticed that people change slowly over time, especially as they grow older. For example, children become more responsible, their voices change, and their interests shift. Even places change — trees grow taller, buildings get older or are replaced, and the environment looks different after a few years.