EDIT: Someone linked to the Wikipedia article for uranium tiles, which says that the majority of the radiation comes from the decay products and is beta radiation[1]. Beta radiation has a weighing factor of 1, which means it's about 0.1 mSv/h. For comparison Wikipedia says:
"90 μSv/h: Natural radiation on a monazite beach near Guarapari, Brazil."
================
EDIT 2: Looking more closely it appears that the dosimeter in the video is switched to µSv/h, so it's reading 0.1 mSv/h anyway and the whole discussion below can be skipped if you're not interested in the difference between Gy and Sv.
==========
Seems to be milliroentgen/h according to another commenter, which is an older unit. Today you'd use Gray (Gy), which is 1 J/kg of energy deposited in material, and Sievert (Sv), which is Gy adjusted by a factor to account for different radiation types and body parts to get comparable biological effects.
For soft tissue (~= humans) 1 R = 0.01 Gy, so the dose would be ~0.1 mGy/h.
Converting that to Sievert is more complicated. Uranium is an alpha emitter, for which you'd use a weighing factor of 20 [0], getting 2mSv/h.
1 mSv/h = "NRC definition of a high radiation area in a nuclear power plant, warranting a chain-link fence." [0]
However alpha radiation also gets blocked by very flimsy barriers, such as a few cm of air, or the layer of dead skin cells on your skin. So the effective dose might be closer to 0!
You also have to consider that the decay products or Uranium are beta emitters. Beta rays have a weighing factor of 1, but they do penetrate deeper (stopped by a few feet of air, can penetrate the skin).
The real effective dose in Sv depends on the exact ratio of decay products to U-238, and how deeply the beta rays of those products penetrate your body (there's different weighing factors for different body parts!).
In conclusion: probably not too much, but radiation and radiation shielding is a complicated subject we managed to spend a whole semester on.
"90 μSv/h: Natural radiation on a monazite beach near Guarapari, Brazil."
================
EDIT 2: Looking more closely it appears that the dosimeter in the video is switched to µSv/h, so it's reading 0.1 mSv/h anyway and the whole discussion below can be skipped if you're not interested in the difference between Gy and Sv.
==========
Seems to be milliroentgen/h according to another commenter, which is an older unit. Today you'd use Gray (Gy), which is 1 J/kg of energy deposited in material, and Sievert (Sv), which is Gy adjusted by a factor to account for different radiation types and body parts to get comparable biological effects.
For soft tissue (~= humans) 1 R = 0.01 Gy, so the dose would be ~0.1 mGy/h. Converting that to Sievert is more complicated. Uranium is an alpha emitter, for which you'd use a weighing factor of 20 [0], getting 2mSv/h.
1 mSv/h = "NRC definition of a high radiation area in a nuclear power plant, warranting a chain-link fence." [0]
However alpha radiation also gets blocked by very flimsy barriers, such as a few cm of air, or the layer of dead skin cells on your skin. So the effective dose might be closer to 0!
You also have to consider that the decay products or Uranium are beta emitters. Beta rays have a weighing factor of 1, but they do penetrate deeper (stopped by a few feet of air, can penetrate the skin).
The real effective dose in Sv depends on the exact ratio of decay products to U-238, and how deeply the beta rays of those products penetrate your body (there's different weighing factors for different body parts!).
In conclusion: probably not too much, but radiation and radiation shielding is a complicated subject we managed to spend a whole semester on.
[0]: https://en.wikipedia.org/wiki/Sievert [1]: https://en.wikipedia.org/wiki/Uranium_tile