Hydrogen gas in the lab emits light with a frequency of 4.50 x 1014 Hz.

Hydrogen gas in stars from distant galaxies is observed to have a frequency of 4.40 x 1014 Hz.

a)Is the galaxy moving towards or away from Earth?

b)Calculate the speed of the galaxy

Tuesday, April 18, 2023Do now:

Hint: c = 3.0 x 108 ms-1

Think-Pair-ShareThink-Pair-Share

What would the spectral shift of What would the spectral shift of galaxies look like if the universe galaxies look like if the universe

was collapsing?was collapsing?

What would cause the universe What would cause the universe to collapse?to collapse?

Today’s KaupapaToday’s Kaupapa::

Today’s TasksToday’s Tasks::

LO5LO5: : Explain the red-shift of stars and Explain the red-shift of stars and how this supports an expanding how this supports an expanding universeuniverse

1)1) Finish Activity 6AFinish Activity 6A2)2) NCEA questionsNCEA questions3)3) Derive Doppler (E/S)Derive Doppler (E/S)

ReminderReminder: : H/W Set 4 (Doppler) H/W Set 4 (Doppler) due Thursday 14due Thursday 14thth Feb Feb

Balloon Ants…Balloon Ants…

VideosVideos

Perimeter Institute (30 min)Perimeter Institute (30 min)- The Mystery of Dark Matter- The Mystery of Dark Matter

TVNZ7 Ever Wondered: TVNZ7 Ever Wondered: Episode 7Episode 7

Tim observes an apparent change in frequency when a helicopter flies directly over his head.

When the helicopter is travelling at 32 ms1 the frequency of the sound wave directly in front of it is 828 Hz. The speed of sound in air is 3.40 102 ms1.

1) Calculate the frequency of the sound wave produced by the helicopter to the correct number of significant figures.

2) The helicopter is not travelling directly towards Tim. Explain how the frequency of the sound wave Tim hears, as the helicopter gets closer, compares with the frequency of the sound wave directly in front of the helicopter (828 Hz).

Do now:Tuesday, April 18, 2023

Solution:Tuesday, April 18, 2023

(M)

(E)