77875
Descrição
Mapa Mental por jakeogilvie, atualizado more than 1 year ago
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Criado por jakeogilvie
mais de 11 anos atrás
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Benefits and risks
- The atmosphere
- Some radiation of the electromagnetic
spectrum is absorbed by the atmosphere,
but some is transmitted.
- Light, some infrared, some ultraviolet, and
microwaves, pass through the atmosphere and
reaches the Earth’s surface. Gamma rays,
X-rays, most of the ultraviolet and some of the
infrared are absorbed by the atmosphere and do
not reach the Earth’s surface.
- Infrared
- Infrared from the Sun reaches the Earth’s surface and warms it. The
warm Earth emits some infrared radiation, and some of this is absorbed
by gases in the atmosphere. This is called the greenhouse effect. If
there was no greenhouse effect, the Earth would be too cold for life as
we know it.
- Infrared from the Sun reaches the Earth’s surface and warms it. The
warm Earth emits some infrared radiation, and some of this is absorbed
by gases in the atmosphere. This is called the greenhouse effect. If
there was no greenhouse effect, the Earth would be too cold for life as
we know it.
- Photosynthesis
- Light from the Sun reaching the Earth’s surface provides the energy for
plants to produce food by photosynthesis. Photosynthesis replaces
carbon dioxide in the atmosphere with oxygen. This reverses the
process of respiration.
- Light from the Sun reaching the Earth’s surface provides the energy for
plants to produce food by photosynthesis. Photosynthesis replaces
carbon dioxide in the atmosphere with oxygen. This reverses the
process of respiration.
- Microwaves
- The atmosphere transmits microwaves, and these can
be used to communicate with satellites.
- The atmosphere transmits microwaves, and these can
be used to communicate with satellites.
- Some radiation of the electromagnetic
spectrum is absorbed by the atmosphere,
but some is transmitted.
- Radiation and cell damage
- Any radiation absorbed by living cells can damage
them by heating them. However, ionising radiations
are more likely to damage living cells. This is because
photons of ionising radiation deliver much more
energy. They can easily kill cells, and can also cause
cancer by damaging the DNA in the nucleus of a cell.
- Effects of microwaves
- Microwaves in the environment may be
harmful, but there is no agreement on this.
They are not ionising, and so cannot cause
cancer in the way that ultraviolet, X-rays or
gamma rays do.
- Microwave ovens work because the food contains water molecules which are made
to vibrate by the microwaves. This means that food absorbs microwaves and gets
hot. The microwaves cannot escape from the oven, because the metal case and the
metal grid on the door reflect microwaves back into the oven.
- Some people think that mobile phones, which transmit and receive
microwaves, may be a health risk. This is not accepted by everyone, as
the intensity of the microwaves is too low to damage tissues by heating,
and microwaves are not ionising.
- Microwaves in the environment may be
harmful, but there is no agreement on this.
They are not ionising, and so cannot cause
cancer in the way that ultraviolet, X-rays or
gamma rays do.
- Ultraviolet
- One health risk which is definitely present in our environment is
ultraviolet, in sunlight. Not much of the ultraviolet reaching the Earth gets
to us, because the ozone layer high up in the atmosphere absorbs most
of it. In the summer, it is wise to use sunscreens and clothing to absorb
ultraviolet, and prevent it reaching the sensitive cells of the skin.
- One health risk which is definitely present in our environment is
ultraviolet, in sunlight. Not much of the ultraviolet reaching the Earth gets
to us, because the ozone layer high up in the atmosphere absorbs most
of it. In the summer, it is wise to use sunscreens and clothing to absorb
ultraviolet, and prevent it reaching the sensitive cells of the skin.
- The ozone layer - Higher tier
- The ozone layer absorbs ultraviolet because
ultraviolet ionises the ozone, which then changes to
oxygen. This chemical change is reversible, and the
oxygen changes back to ozone.
- The ozone layer absorbs ultraviolet because
ultraviolet ionises the ozone, which then changes to
oxygen. This chemical change is reversible, and the
oxygen changes back to ozone.
- Any radiation absorbed by living cells can damage
them by heating them. However, ionising radiations
are more likely to damage living cells. This is because
photons of ionising radiation deliver much more
energy. They can easily kill cells, and can also cause
cancer by damaging the DNA in the nucleus of a cell.
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