Skip to main content

The Twinkling Star: Activity on Atmospheric Refraction

 


Twinkle, twinkle, little star,

How I wonder what you are!

Up above the world so high,

Like a diamond in the sky.....

We all remember how we all use to sing and love this poem. This poem was first published with the title ‘The Star’ in 1806 in Rhymes for the Nursery, a collection of poems by Jane Taylor and her sister Ann Taylor.

This poem makes kids admire stars in the night sky and also encourages some of them to even study astronomy as they grow up

But, do stars really twinkle? If not, why do they seem to twinkle? In this project, we will perform an activity

to find the answers.


Things We Need


Setting Up the Experiment

  • Wrap a small piece of tape around the laser pointer so that it pushes down its On button and the laser point remains in a working position.
  • Place the pan over the induction cooktop. Now, stack some books beside the cooktop and rest the laser pointer on the books. Make sure that the laser’s beam passes no more than 1-2 centimeters over the induction pan's surface.
  • Tape the printed image of the human eyes to the wall with the leaser pointing directly at the center of one of the eyes.
  • Turn On the induction cooktop and observe the laser beam on the printout.

The Twinkling(appeared) of Star

We observe that at first the laser spot on the eye is steady. There is no flickering/wobbling of the laser spot. But as the pan gets hot, we will notice the laser spot starts to wobble and flicker.

But why the laser spot starts wobbling?

This is due to the Refraction of light. In simple terms:

"Refraction is the bending(change in direction) of a light wave as it passes from one transparent substance into another, having different density". This happens mainly because the speed of light in a rarer medium is greater than its speed in a denser medium.

But what refraction has to do with this wobbling?

Refraction is the change in direction of light(wave) passing from one medium to another caused by a change in its speed.

When air near the hot plan heats up, it becomes less dense. This density change causes the air to rise and mix with the surrounding cooler air in a process called convection. Now, due to refraction light passes through hot air(optically rarer) more quickly than it does through the cool air(optically denser). This slight change in speed causes the light to bend as it passes through the air of varying temperatures which makes us perceive the laser spot to flicker and wobble?

But how this relates to the twinkling of stars?

The Earth’s atmosphere is a layer of air., As light from a star races through our atmosphere, it bounces and bumps through the different layers, bending the light before you see it. Since the hot and cold layers of air keep moving, the bending of the light changes too, which causes the star’s appearance to wobble or twinkle.

Please feel free to suggest any improvement, variation, or correction to this experiment. Thank you.









Labels:
Location: Dehradun, Uttarakhand, India

Comments

Post a Comment

Popular posts from this blog

Rose Window with Tinkercad

I love to study ancient civilizations and architecture. Last summer I attended a 3D printing workshop, "Tinkering with Tinkecad" at my school. At the workshop, I learned how 3D printing is not only revolutionizing STEM learning but also aiding other streams like Geography and History. I learned how I can print out historical artifacts to examine and understand them much better. Here, I'm sharing how I used Codeblocks to create the Rose Window of the Abbey of Fiastra . Things We Need Computer Internet 3D software ( Tinkercad ) Computer mice, 3D printer, and filaments for printing(optional) Division For convenience, we will divide the Rose Window into 2 parts,   Inner Shell  and  Outer Shell . Inner Shell: Division and Identification The Inner shell of the Rose Window can divide it into 3 parts: Central Part:   made up of a solid cylinder at the center with hole cylinder with 12 cylindrical holes with the base pointing towards you. Middle Part:   is made up of ...
1 comment
Read more

Bernoulli’s Mist Sprayer

  No doubt students learn more when they are mentally and physically engaged in the learning process, regardless of the subject they are studying, and when it comes to STEM education , hands-on experiential learning is an indispensable part of the learning process. In this hands-on activity, we will make a water sprayer using two straws, and experience Bernoulli’s Theorem . Category:  Physics Sub Topic:   Fluid Pressure Time Required : 20-30 min Difficulty:  Easy Things We Need 2 Straws (4 inches each) Insulation Tape Eraser Scissors A glass of water Assembly Pic 1:   Cut two insulation tape pieces and attach them to either end of both the straws. Pic 2:   While attaching the tape, make sure to leave some space from the end(4-5mm approx). Pic 3 : Tape the 1st straw(I used Green straw as 1st) to the eraser so that the straw is exactly aligned with the edge of the eraser. Pic 4:   Next, tape the second straw(I used Orange straw as 2nd) to the edge of th...
Post a Comment
Read more

Space Invader With MakeCode

  Microsoft MakeCode is a framework for creating interactive and engaging programming experiences for those new to the world of programming. The platform provides the foundation for a tailored coding experience to create and run user programs on actual hardware or in a simulated target. MakeCode uses the blocks programming model to let the user learn coding concepts in a more tangible fashion. The blocks map directly to actual lines of code in a programming language. So, once a user has a sense of confidence and familiarity with how the blocks work, they can transition to coding more complex programs in the programming language itself. In this Instructable,  we'll develop  a simplified version of the classic ' Space Invaders ' game using Microsoft MakeCode. As opposed to the real game of Space Invaders game, our Invader(enemy) will be firing and moving horizontally across the top of the screen. The player will control a laser cannon by moving it horizontally across the ...
Post a Comment
Read more