Invisible pens and Ink
Hello everybody!
I have made a document on why invisible ink shows in UV light,and how.
I have looked into this,because my best friend,Emma-Louise Seth came over to play,and I had these cool spy pens.They are from Smiggles,and they have a normal pen at the back,and a white pen that writes in invisible ink at the front!The lid has a UV light,and when you shine it on the white pen invisible ink,the ink shows!
Here is the document:
UV light and invisible ink
Why does invisible ink glow in UV/black light?
Have you ever wondered why invisible ink glows in UV light?Well,that is because when the UV light hits the invisible ink,the light,UV,is at the high energy side of the spectrum.At the very high frequency end.You know what that means!When the light hits the atoms of the fluorescent ink,the electrons in the atom absorb the energy from the black light,a.k.a UV light and start jumping vigorously,thus giving the glow we see.
(Image from http://www.ces.fau.edu/nasa/module-2/radiation-sun.php)
Why only in UV light?
Well,you know how when the UV light hits the fluorescent ink,it glows.All the atoms in the fluorescent ink will absorb the light,and the electrons will start to jump to the shell outside it,and then very slowly comes back to the original shell.When it jumps,it bring out the energy that came from the UV light.White light doesn’t have the energy to cause all the electrons to jump.Thus,it creates the glowing with only UV light.
By Maya.
By,
Maya.
