2926: Doppler Effect

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Doppler Effect

Title text: The Doppler effect is a mysterious wavelength-shifting phenomenon which seems to primarily affect sirens, which is why the 🚨 emoji is red.

Explanation

This explanation may be incomplete or incorrect: Created by an ALARMED BOT THAT GOES... - Please change this comment when editing this page. Do NOT delete this tag too soon. If you can address this issue, please edit the page! Thanks.

Miss Lenhart is teaching a class about about the concept of redshift and using the Doppler effect as a demonstration. However, she gets distracted by how cool sirens are and doesn’t explain fully the concept of redshift.

In the second and third panels, Miss Lenhart talks about the strange noise sirens (and cars) make when the pass you. This noise is created because the sound waves are compressed in front of the car due to it traveling in the same direction of the waves, similare to how a {{https://www.youtube.com/watch?time_continue=204&v=436i_cTdtVo&embeds_referring_euri=https%3A%2F%2Fwww.google.com%2F&source_ve_path=Mjg2NjY&feature=emb_logo%7Cbullet fired forward from a car|}} gains the cars extra speed. The compressed waves create a louder, higher pitched sound, then as the car passes, the noise gets considerably softer and lower. The latter is because the waves are now being stretched out as they are moving in the oppisite dirrection of their "creator", like a gun shot backwards from a car.

Redshift is a concept that the farther away an object is, the more red it appears beacuse light has to travel farther to get to a galaxy making it look longer than it is.

Transcript

This transcript is incomplete. Please help editing it! Thanks.

[Miss Lenhart is pointing with a stick to a whiteboard with various scientific drawings and words, including but not only a graph.]

Miss Lenhart: The more distant a galaxy is, the redder its light.

Miss Lenhart: Why? Well, that's an interesting question.

[Zoom in on Miss Lenhart]

Miss Lenhart: Ever notice how, when a siren is approaching, it sounds like Bweeeeeeeeee...

[Zoom in on Miss Lenhart with her arms raised]

Miss Lenhart: ...but then it zooms past and goes Nyeeeooooowww?

Miss Lenhart: And sometimes they hit a button that makes it go Pyeew! Pyeew! really loud?

[Miss Lenhart with his finger raised standing in front of the whiteboard]

Miss Lenhart: And in Europe they go Oooo^eeeeoooo^eeee...

Off-panel voice: So why are galaxies red?

Miss Lenhart: Oh, no idea.

Miss Lenhart: Anyway, another siren I like is...

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