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The plagues in context - According to the Book of Exodus, God inflicted plagues on Egypt to persuade the Pharaoh to free the Israelite slaves. The Pharaoh only accepted God's request after the tenth plague. Proponents of biblical archaeology have offered up two theories to explain the events.

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Two theories - British physicist Colin Humphreys, author of the book 'Miracles of the Exodus' (2003), argues that an extreme drought was responsible for changing the water of the Nile, which precipitated the series of events. Others theorize that a volcanic eruption caused the sequence of plagues 3,500 years ago. Canadian biologist Siro Trevisanato, who wrote the book 'The Plagues of Egypt' (2005), is a proponent of this idea.

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First plague: water into blood -

The first divine plague occurred when Pharaoh Ramesses II refused to free the Israelites. The water of the Nile, which symbolized fertility, turned to blood.

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First plague: water into blood - One scientific explanation is that a rise in temperature led to an extreme drought and turned the Nile red. The heat generated a proliferation of pyrophytic algae, which caused the color to change.

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First plague: water into blood - Another hypothesis is that the river changed color because of earthquakes triggered by a volcanic eruption. The quakes disturbed dissolved iron deposits in the water, which mixed with gases released by the tremors to form ferrous hydroxide (rust), turning the water red.

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Second plague: frogs - According to Exodus, Pharaoh Ramesses II still resisted freeing the Israelites from slavery. Accordingly, another divine punishment was imposed: the invasion of the river bank and beyond by thousands of amphibians.

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Second plague: frogs - According to the British physicist Colin Humphreys, this "curse" was a direct consequence of the first. With diminishing levels of oxygen in the water, the frogs fled the river and migrated to land. Meanwhile, numerous fish died in the Nile.

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Second plague: frogs - The volcanic eruption theory posits that the toxic gases released by the earthquakes starved the water of oxygen, forcing the frogs to flee to dry land.

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Third plague: lice - The Egyptians prayed for an end to this terrible series of plagues. But a third punishment was bestowed upon them.

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Third plague: lice - According to Colin Humphreys, the drought led to the multiplication of lice eggs. The parasite was a common scourge in ancient Egypt, and the reason why many people shaved their heads.

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Third plague: lice - Another modern explanation suggests the proliferation of parasites was a direct result of the increasingly unhygienic nature of the Nile as its waters became more polluted.

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Fourth plague: flies - A swarm of flies followed the lice infestation. While the Egyptians suffered greatly from this latest plague, the Israelites were not at all affected by this airborne assault.

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Fourth plague: flies - In his book, Colin Humphreys believes  the insect invasion was entirely due to the demise of the amphibians, whose main food source were these flying insects—less frogs, more flies!

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Fourth plague: flies - Another theory suggests that the lack of clean water and so many dead animals simply attracted more flies to the region.

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Fifth plague: diseased livestock - The Bible says that Ramesses II lied to Moses and told him that he would free the slaves. When his deception was discovered, Egypt was punished with the demise of its domestic animal population.

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Fifth plague: diseased livestock - One explanation for the death of so many animals is the so-called cascade effect. Infestations of flies and lice promoted by the lack of clean water, plus the decimation of the frogs (natural predators of the insects), were all factors in causing this latest "plague."

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Fifth plague: diseased livestock - Humphreys theorizes that stable flies transmitted fatal viruses to horses and cows.

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Sixth plague: boils -

Exodus has it that the Egyptians were next afflicted with boils on the skin.

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Sixth plague: boils - According to biologist Werner Kloas of the Leibniz Institute in Germany, boils appeared due to the multiplication of insects, which stung and bit the hapless Egyptians.

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Sixth plague: boils - The volcanic eruption theory underlines the belief that escaped carbon dioxide resulted in festering boils and infected wounds.

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Seventh plague: hailstorms - A seventh plague brought with it a frightening storm of hail, ashes, and fire, which fell from the sky. 

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Seventh plague: thunderstorm of hail - One simple theory suggests that the tempest was a rare hail storm that included thunder and lightning. Although scarce, it is possible for such weather phenomena to occur in desert regions.

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Seventh plague: thunderstorm of hail - Nadine von Blohm of the Institute of Atmospheric Physics of Germany theorizes that the event was a rain of stones caused by a volcanic eruption.

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Eighth plague: locusts - Exodus says that God delivered this punishment in order to destroy crops in the region. Again, the Israelites escaped the curse.

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Eight plague: locusts - According to Humphreys' book 'The Miracles of the Exodus,' locusts invaded Egypt on the back of a change in climate, and that the crop destruction was because of the force of the hailstones and/or volcanic activity.

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Eight plague: locusts - A second theory is that the cold weather and damp soil created an ideal breeding ground for the flying pests. 

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Ninth plague: darkness -

Exodus states that total darkness descended for three days.

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Ninth plague: darkness - One theory is that a dense sandstorm may have been responsible for the phenomenon. Such storms occur in the deserts of Egypt today.

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Ninth plague: darkness - The volcanic theory posits that the ashes caused by the eruption eclipsed the sun and left Egypt in darkness.

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Tenth plague: death of firstborn - According to the Bible, the first infant of both humans and animals died. Only the Israelites, who had been warned to mark their doors with the blood of a lamb, would be saved. Pharaoh Ramesses II lost his son in this plague.

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Tenth plague: death of firstborn - Modern scholars believe that deaths of firstborn children had its origin in a cultural habit at the time. Firstborn children had the privilege of being fed first. They ate food contaminated by locust feces and died of disease.

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Tenth plague: death of firstborn -

Another theory is that the firstborns died due to carbon dioxide released by the volcano. The vulnerable infants would have died from inhalation of the toxic gas.

See also: Can these be the lost books of the Bible?

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