Saturday, September 23, 2017
You are viewing:
Science & Technology
> Viewing video
Welcome Guest (
Science & Technology
How much does a shadow weigh ?
Michael attempts to determine whether or not it is possible to actually weigh a shadow.
<< Previous video
Growing beef in a laboratory
Next video >>
Building the largest ever space telescope
Recent comments on this video
#15 Posted by
on 5 February, 2014, 20:22
We don't know that, so far we only know is that a photon ( the main component of light) is smaller than 1×10?18 eV/c2. That is about the smallest measurement we can make. But given that gravitation affects light it must have a mass. I think 029b10 was making a reference to the old song "He ain't heavy, He's my Brother"...
#16 Posted by
on 6 February, 2014, 11:26
give him a few minutes, he might figure it out....
#17 Posted by
on 6 February, 2014, 11:53
all electromagnetic radiation produces radiant pressure ... it pushes on things... i wonder if that force adds to the weight of an object being pushed/radiated on? But i would guess that the shadow itself weighs Nothing... the space between the object casting the shadow and the shadow itself is where we might find a 'difference'? ... as compared to the surrounding areas containing more light? ... if a tree casts a shadow, but there is no one there to see it, does the sun exist? LOL ( just a silly twist on that old thing.)
#18 Posted by
on 6 February, 2014, 21:17
Ok, do not know much about photons, so this may sound like a silly question, but hey, I still want to ask it: Without a background surface, there would be no shadow in the first place, whatever the light, so IF a shadow did have a weight, would it not have to be based on the weight of the surface it has shadowed on? Eg: a shadow on a curtain would weight less than a shadow against concrete.
#19 Posted by
on 6 February, 2014, 22:53
Am thinking I'll put my shadow on a diet.
#20 Posted by
on 6 February, 2014, 23:04
Ok, do not know much about photons, so this may sound like a silly question, but hey, I still want to ask it: Without a background surface, there would be no shadow in the first place, whatever the light, so IF a shadow did have a weight, would it not have to be based on the weight of the surface it has shadowed on? Eg: a shadow on a curtain would weight less than a shadow against concrete. Nope. Imagine the weight of a noise and you will have an idea about the weight of a shadow.
#21 Posted by
on 7 February, 2014, 0:01
hmmm ... in that case .. do we weigh less in the dark?! (lol) You mean... instead of dieting and exercise, I can lose weight by closing my eyes? .
#22 Posted by
on 7 February, 2014, 13:58
The question "How much does a shadow weigh?" misrepresents the concept of weight in a scientific context. Weight is how we measure gravity's affect on a mass, and photon's have no mass. The reason photon's are able to exert a force is due to their having momentum*, which is quite different to mass. Measuring the difference in that force between light and unlit (shadowed) areas would simply provide the proof of this momentum, it would not indicate the shadow has 'weight'. * While momentum is calculated using the equation p = mv, which would imply the photon does have mass (the m in the equation...
#23 Posted by
on 7 February, 2014, 14:04
Thanks for that; photons can't have mass and still travel at light speed. But that is all beside the point. We are talking not about the weight of the light hitting the object casting the shadow but the weight of the absence of photons behind it. I hope that makes the answer obvious.
#24 Posted by
on 7 February, 2014, 14:20
Thanks for that; photons can't have mass and still travel at light speed. But that is all beside the point. We are talking not about the weight of the light hitting the object casting the shadow but the weight of the absence of photons behind it. I hope that makes the answer obvious. It's still a misunderstanding of weight. Take this scenario. You weigh yourself while standing in sunlight, and then weigh yourself while in shadow. If the scales were accurate enough, you would notice a difference between the two measurements. Does that mean a shadow has 'negative weight'? No. Sunlight applies a ...
Click here to view all 24 comments on this story
to post a comment.
Last updated forum topics
Ancient Mysteries & Alternative History
James Cameron finds 'evidence of Atlantis'
Ruins seen or found on Google Earth
Hamas says it is ready to hold elections
Kurds ready to 'pay any price' for freedom
US troops exchange fire with Turkish proxies
Philosophy and Psychology
Let's Discuss: Affirmations.
Fear of death
How to explain existence of God from reality
Extraterrestrial Life & The UFO Phenomenon
Some other perspective
Canada's best UFO sighting still intrigues
Recent news in this category
Man who prevented World War 3 dies aged 77
Posted 9-22-2017 |
Former Soviet military officer Stanislav Petrov made a decision in 1983 that may have saved the world.
Italian supervolcano's magma source found
Posted 9-18-2017 |
Scientists have discovered evidence of a 'hot zone' feeding a supervolcano in southern Italy.
Scientist electrocutes himself with an eel
Posted 9-17-2017 |
One biologist decided to take a hands-on approach to studying the powerful shock of an electric eel.
What would you do in a zombie apocalypse ?
Posted 9-17-2017 |
A new poll in the UK has revealed that some people may already be preparing for such an eventuality.
Computers may replace doctors within 10 years
Posted 9-13-2017 |
UK Health Secretary Jeremy Hunt has outlined how health care is likely to change over the next decade.
'Tunable' mirror can change in to a window
Posted 9-12-2017 |
Scientists have developed a special type of mirror that can transition in to a window and back again.
Earth is now a hybrid world, say scientists
Posted 9-9-2017 |
Researchers in the US have come up with a revised classification system to help categorize our planet.
Scientists invent whole new type of chocolate
Posted 9-6-2017 |
Named 'Ruby', the intriguing pink-hued delicacy is the first new type of chocolate in 80 years.
More news in this category
UM-X 10.7 Unexplained-Mysteries.com © 2001-2017