CARL AZUZ, CNN 10 ANCHOR: Hi. I'm Carl Azuz. And you know what? Fridays are awesome! This is CNN 10.
Let's go to where the past has met the present. Frankfurt, Germany, is a city of more than 700,000 people in the west central part of the country. And more than 60,000 of them will have to leave their homes this weekend because a bomb was found near the center of the city. It's both an explosive and a relic.
This bomb was dropped by a British plane during World War II, but it wasn't discovered until this week, during construction near part of a university. It's a large explosive, 1.4 tons, capable of leveling a city block. And though police say there's no danger to the public right now, they want the area cleared out on Sunday morning before they start the work of defusing it.
According to America's Smithsonian Institution, half the bombs dropped on Europe during World War II fell on Germany and as much as 10 percent of them never went off. Reconstruction in the country started shortly after the war was over and more than seven decades later, many bombs still turned up in Germany every year.
They're old but dangerous, requiring bomb disposal experts to find, defuse and get them away from the public. The upcoming evacuation in Frankfurt is one of the largest since the war.
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AZUZ (voice-over): Ten-second trivia:
In terms of financial impact, which of these natural disasters was costliest?
Hurricane Katrina, Hurricane Andrew, "Superstorm" Sandy, or the 1935 Labor Day Hurricane?
Damage from Hurricane Katrina is estimated at $108 billion, making it the costliest hurricane in U.S. history.
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AZUZ: But the damage from Hurricane Harvey could break that record. The White House says that about 100,000 homes have been affected by the storm, and as of last night, 39 people have lost their lives, though officials expected that number to increase.
Texas Governor Greg Abbott declared this Sunday a Texas Day of Prayer for the future of the state, the future of the country, for healing, hope and rebuilding. And as the waters start to recede in Texas, the cost of recovery efforts is growing, and the White House is preparing a request to Congress for emergency funding to deal with the aftermath of the hurricane.
This video was taken over the southeast Texas city of Beaumont Wednesday afternoon. One thing you'll notice is that there's no dry ground. Every house, every building, very business in this area is surrounded by water, and yet, there's no clean running water.
Flooding caused two water pumps to fail. That means that many of the thousands who are in Beaumont are lining up and waiting for hours to get bottled water, when the local stores can get it (ph). Some are even rationing what they sell. Without running water, the Baptist hospitals of southeast Texas had to shutdown and send patients to other facilities. Even some evacuation shelters have flooded. There's too little clean water, too much dirty floodwater and that carries unseen dangers of its own.
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SUBTITLE: The hidden dangers of flooding.
ELIZABETH COHEN, CNN SENIOR MEDICAL CORRESPONDENT (voice-over): Hidden dangers can lurk in floodwater. Alligators, snakes, even floating fire ants could be nearby.
Water in a flooded basement can carry an electric current, downed power line submerged in floodwater can also shock.
Waste from humans and animals can seep into the water, swallowing fecal bacteria can cause gastroenteritis, nausea, vomiting and diarrhea.
If you had any open cuts or sores, viruses and bacteria such as tetanus may infect them.
Under flood water, nails and fragments of metal and glass may go unseen, leading to possible injuries and infections.
Floodwater can cause structural damage. Submerged stairs and floors may be unsafe.
Oil, gasoline and pesticides, and other toxic agents can contaminate floodwater. Some chemicals in floodwater can cause headaches, skin rashes and other signs of chemical poisoning.
Fungi can grow from moisture and standing floodwater. They can often be seen and smelled. Breathing in mold can trigger allergies and sometimes cause a major infection.
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AZUZ: We regularly feature technology stories on CNN 10. The field is always making news because it's always changing. There's always something new. One example: hydrogels. These are basically water held together by plastic.
Their downsides have included concerns that they can be tough to work with. They maybe hard to make sterol, which is important for medical uses and they tend to be weak. But part of that might have been solved.
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REPORTER: This might be the future of joint replacements. No, not home, this, the white stuff between the two clamps. It's a brand new super material that won't tear when he or her or this guy or even this guy gives it all they've got.
And that's why this stuff is so extraordinary. It combines the strength of metal, with the flexibility of Jell-o and it could revolutionize how we grow old.
Hydrogels are all around us, in soft contact lenses, disposable diapers, even food. There are natural hydrogels in our tissues and organs, and synthetic ones like the kind made here.
They're solid objects but consist mostly of water. They're soft and flexible, but also incredibly weak. Until now.
In Sapporo, scientists have created a hydrogel that's five times stronger than steel.
PROF. JIAN PING GONG, DISTINGUISHED PROFESSORE, HOKKAIDO UNIVERSITY: It's the strongest soft material ever been obtained by human beings.
REPORTER: Professor Jian Ping Gong is one of the world's top hydrogel experts. For this latest one, she and her team combined fiber glass fabric, with a strong hydrogel. Sharp objects can cut through it, but it wouldn't tear. Ripping this would require more energy than splitting steel.
GONG: The invention of tough hydrogels changes all the opinions or views against this material.
REPORTER: The team believes this will revolutionize joint replacements. Synthetic hydrogels are similar to human tissue, both soft and flexible, which means they make great substitutes for ligaments or tendons. But until now, synthetic hydrogels have been too weak to withstand the joint's every day wear and tear.
Professor Gong's invention though changes that. With this fiber reinforced hydrogel, surgeons could make strong artificial ligaments that would be closer to the real thing, a big improvement on how we do it today.
GONG: For example, for the artificial knee, they use ceramics and plastics and metals. This hard material is very stiff, so they do not have shock absorbing properties.
REPORTER: But the professor's ideas don't always stay in the lab.
GONG: When I see a flower coming from a very hard concrete crack, I was wondering why the small flower has such a big, large energy to come out.
REPORTER: And that's the key to her success, finding and harnessing strength in the most unexpected of places.
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AZUZ: For our last story ahead of this three-day weekend, it's time to play guess what this is. Unless you're a chemical engineer, you won't. So, we'll just go ahead and tell you it's a ferrofluid. Why, of course. A ferrofluid is a mix of oil and iron particles. The iron seems to come alive when it's exposed to magnets.
Ferrofluids have been around for decades. They're used in everything, from x-ray, generators, to loud speakers. In this case, they're being manipulated and shown off by a group of French artists -- who are pretty ferrocious in their ferrolous ferrosuit of ferrosinuating ferrofection. They keep things pretty fluid, they must have an iron will and if they really want to test their mettle, they just add oil.
I'm Carl Azuz for CNN 10. We'll see you Tuesday after the Labor Day holiday. Have a great weekend ahead.