How Did Galileo's Experiment Measure the Speed of Light?

  • Context: High School 
  • Thread starter Thread starter Questioner...
  • Start date Start date
  • Tags Tags
    Fire Light
Click For Summary

Discussion Overview

The discussion centers on the historical measurement of the speed of light, specifically focusing on Galileo's early experiments and the methods used to determine this speed. Participants explore the implications of using different light sources, such as burning chemicals, and question whether variations in light speed exist.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant inquires about the initial methods used to measure the speed of light and suggests conducting experiments with different burning chemicals to investigate potential variations in speed.
  • Another participant asserts that all colors of light travel at the same speed in a vacuum and references historical measurements, including observations of Jupiter's orbit.
  • A participant describes Galileo's experiment involving lanterns on hilltops, noting that the high speed of light rendered his attempt ineffective.
  • A response suggests that the original poster should utilize online resources for further information.

Areas of Agreement / Disagreement

Participants express differing views on the possibility of light having different speeds based on the source, while there is a general consensus on the historical significance of Galileo's experiment and the understanding that light travels at a constant speed in a vacuum.

Contextual Notes

Some limitations include the assumptions about the uniformity of light speed across different wavelengths and the historical context of Galileo's experiment, which may not account for modern understandings of light and its properties.

Questioner...
Messages
8
Reaction score
0
Hello again, Here to ask a few more questions.
I previously asked a question about light and weather or not it could possibly have different speeds. But I recently realized that the burning of different chemicals can have different tones of light.

I would like to know how exactly we first measured how fast the speed of light was, what we used as a source, and if we could conduct an experiment using the light from different burning chemicals to find out if there is a different speed- or if it already has been done let me know.

Thanks
-Q?
 
Physics news on Phys.org
different colors of light all travel at the same speed in a vacuum (i.e. radio waves, x-rays, blue, red, etc.). The first decent record of the speed of light was done by observing the perceived lag in the orbit of jupiter. That was over 3 centuries ago. Now any child in a high school science lab (well, a high school science lab with good funding) can measure the speed of light to pretty high accuracy.
 
the first attempt at figuring out the speed of light was conducted by Galileo. Galileo and an assistant each took a shrouded lamp and stood within sight of each other on two widely-separated hilltops.

Galileo opened his lantern, and when the assistant saw its light, he opened his, too.

Galileo measured the time it took from when he opened his lantern to when he saw his assistant's lamp, which should be the time for light to travel back and forth between the two hilltops.

of course, due to light's high speed, his experiment epic failed.
 

Similar threads

Undergrad Speed of information in a medium
  • · Replies 38 ·
2
Replies
38
Views
5K
High School Thought experiment: Beyond the slowest measurable speed?
  • · Replies 20 ·
Replies
20
Views
2K
High School How does a wave collapse not violate the speed of light?
  • · Replies 3 ·
Replies
3
Views
2K
High School One-Way Speed of Light
  • · Replies 93 ·
4
Replies
93
Views
6K
High School Why do photon polarization experiments show similar outcomes in different situations?
  • · Replies 11 ·
Replies
11
Views
3K
High School Meaningfulness of the speed of light
  • · Replies 25 ·
Replies
25
Views
2K
High School Special Relativity violation via Quantum Mechanics?
  • · Replies 12 ·
Replies
12
Views
2K
High School How do we know that the measurement affects the result?
  • · Replies 15 ·
Replies
15
Views
2K
Undergrad How to rule out that the speed of light was different in the past?
  • · Replies 76 ·
3
Replies
76
Views
6K
Undergrad Why is Rømer's light speed measurement not one-way?
  • · Replies 42 ·
2
Replies
42
Views
3K