How can you make something invisible, that is, without using a cloak? This easy experiment just might be the “solution.”
A new YouTube video from At-Bristol, a science center in England, shows how you can use light to make something disappear in the blink of an eye. Just check it out above.
All you need is a couple of pyrex glasses and a sweetener called glycerol — if you can’t find that, vegetable oil and baby oil will also work. You might want to grab a pair of gloves too, because the experiment can get a bit sticky.
“Here I have a beaker full of glycerol,” science educator Ross Exton says in the video. “If I take a pyrex test tube and place it into the beaker, we can still see it because of the air in the tube — but if I dip it just below the surface, it vanishes.”
Awesome.
But as Exton explains, the reason for this isn’t magic. See, in a beaker of normal water, “as light passes from one material to another, it changes speed and direction,” Exton says in the video, “allowing us to the see edges of the tube.”
That’s because the beaker and the water have different so-called refractive index, meaning light travels through them at different speeds.
What makes glycerol so special is it has the same refractive index as pyrex glass — so when light passes through a beaker full of glycerol, it doesn’t change speed and direction. And as a result, it doesn’t reveal the test tube hidden inside. Voila!
How can you make something invisible, that is, without using a cloak? This easy experiment just might be the “solution.”
A new YouTube video from At-Bristol, a science center in England, shows how you can use light to make something disappear in the blink of an eye. Just check it out above.
All you need is a couple of pyrex glasses and a sweetener called glycerol — if you can’t find that, vegetable oil and baby oil will also work. You might want to grab a pair of gloves too, because the experiment can get a bit sticky.
“Here I have a beaker full of glycerol,” science educator Ross Exton says in the video. “If I take a pyrex test tube and place it into the beaker, we can still see it because of the air in the tube — but if I dip it just below the surface, it vanishes.”
Awesome.
But as Exton explains, the reason for this isn’t magic. See, in a beaker of normal water, “as light passes from one material to another, it changes speed and direction,” Exton says in the video, “allowing us to the see edges of the tube.”
That’s because the beaker and the water have different so-called refractive index, meaning light travels through them at different speeds.
What makes glycerol so special is it has the same refractive index as pyrex glass — so when light passes through a beaker full of glycerol, it doesn’t change speed and direction. And as a result, it doesn’t reveal the test tube hidden inside. Voila!
