Pistol Shrimp Bot

The pistol shrimp used to astound scientists: It did...something..., and then fish in front of it abruptly dropped dead. The fishy victim is then pulled inside the pistol shrimp's burrow and devoured. Clearly, this had to be studied.
It was discovered how this works by filming the shrimp firing in slow motion. All the shrimp does is close its claw really really fast. The rapidly increasing pressure causes a cavitation bubble with temperatures rivaling the surface of the sun. This then, surrounded by seawater, explodes slightly as everything condenses back to normal. The heat, pressure, and shock wave all injure the shrimp's prey, usually adding up to a fatality. And knowing all this gave me the idea to weaponize it.
The weaponized pistol shrimp robot would swim up to things we don't like underwater, such as the propellers of an enemy submarine. It would then bring a massive claw as close as possible as close to the propellers as possible, and then very abruptly close it. With a loud banging sound, the propellers are promptly damaged by the ensuing cavitation bubble, as cavitation is the bane of naval propellers everywhere. The submarine is now mobility-killed, and can be finished off with a cleverly placed depth charge if it continues to cause problems. Or if this is done to a surface ship, that ship isn't sailing anywhere anytime soon. If it causes more problems, it'll wind up torpedoed, or we could cavitation attack the hull to sink it.
The robot can then swim to the next target, as an enemy that has one boat probably has a lot more.
Unfortunately, this won't be too useful in modern warfare, as all our battles are mostly against asymmetric enemies who don't have navies, because they aren't nations. Most of our enemies now are insurgents, and stopping them requires a whole different type of fighting than the kind that stops nations.

Printing a brain

Printed organs offer a major step towards immortality. I could take one cell from each of my organs, and use it to grow a brand new spare. I would then be guaranteed a very long life indeed, because disease or damage could be repaired fairly quickly by swapping my organs. Arteriosclerosis? New heart, no problem. Lung virus? New lungs. Cirrhosis? New liver. There'd be no chance of rejection, because they're grown from my own cells, and the cost would rapidly reduce over time from an economy of scale. However, if I had a stroke, or brain damage due to concussion, or became demented, I couldn't exactly swap out my brain. Or could I?
While if my brain were directly swapped out entirely, I would definitely be a different person, suppose only a small amount were changed at any given time. Starting with the moment that my doctor suspects that I'm developing a brain condition, I have a small amount of my brain biopsied and replaced with a printed copy of that section. This is allowed to heal and integrate back into my brain. Then a section a few inches further is biopsied and replaced, and over the course of about five years or so, every single piece is replaced. During the healing time, the neurons reestablish their connections, so at no point do I lose psychological continuity. And when the replacing is done, I have the brain of a twenty year old. If this works, then printing will make everyone immortal eventually. Well, not totally immortal, as you could still die from injuries, or if you have a brain condition that kills you in less time than it takes to replace-and-heal. But unaging and generally free of disease.
Or would you slowly lose your memory and personality over the course of the replacement?

Printing Organs

An interesting innovation of modern times is deposition printers, which can produce any 3 dimensional object by laying it down layer by layer in melted plastic, which rapidly cools and solidifies into a layer of the final object. If an layer can't support itself structurally until complete, the system can also lay down a second type of plastic that washes away when exposed to water. Although the systems tend to be expensive (none cost less than $500), once you own one, you can have all the plastic parts you want for a few cents worth of thermoplastic.
Medical doctors have especially taken note. Human cells can be grown in a lab, but only in flat sheets about one cell thick. The cells know that they shouldn't endlessly grow upon each other, because when they do that, they're typically cancer. Cells in your body grow on a framework, an extracellular matrix. And here's where they have the idea.
Since the 3d printer can print any shape, have it print an extracellular matrix for an organ, wash it, and introduce it to a glucose-and-saline medium. Inject one human cell, and a short time later, you have a fully functional organ. Since extracellular matrix parts are regularly replaced, this new organ will, after being implanted, slowly replace its plastic extracellular matrix with a real one, at which point the organ will be indistinguishable from the original. Other than the new one is fresh and healthy and will last for years longer.
This is giving me an even crazier idea, which I will go into tomorrow.

The Solar Road

Every summer, America's roadways become miserable hot strips that go on and on for miles, adding to the already hot and miserable condition of the weather. The black asphalt soaks up the sun, producing loads more heat. This of course, has given scientists a genius idea: replace it all with solar panels. Wait, what?
The idea revolves around glass. Glass that can support the weight of all the cars, but is totally transparent. Beneath this glass road is an endless extent of solar panels that turn the light of the sun shining upon them into electric power. Sometimes this is interrupted by a car driving over it, but there would be more sun than not.
Due to the sheer bulk of Americas roads, much of them in rural areas where cars don't drive over them for days at a time, replacing all roads with this new kind would produce enough power to keep the entire country running. Dirtier powers like Oil, Coal, and even Nuclear would be practically obsolete. (China would take note, I'm sure.)

Heat Power

Lady Ada tells me that there's an interesting new material that's been developed. It is an alloy that develops a magnetic field in proportion to its temperature. There are some immediate implications to this, most startlingly that it is now possible to turn heat into electricity.
This produces electricity because electricity is produced by a varying magnetic field near a loop of copper wire. Traditional power plants use a spinning magnet -- the wire is exposed to different magnetic fields as the magnet turns. This system would instead produce a magnetic field that changed as the temperature did. As it heats up, the field gets stronger, and as it cools off, the field gets weaker. So if you left it in the sun, it would start to heat up starting a little after dawn, until sunset, when it would be quite hot indeed. After dark, it would cool off. Cyclically, this would produce power, over a longer frame than solar cells because there are no moving parts.
However, the sun isn't the only thing that heats this thing up. You could use car exhaust, fire, nuclear waste, or in colder climates, even just grabbing it periodically. (Less than pleasant, though). The possibilities are literally endless, as heat is the most entropic form of energy, therefore almost all energy-using processes will produce heat. And now that heat can give you some of its energy back as electricity.

Ionization Theory

A common theory states that indoor air quality can be greatly improved by electrically charging the air. Air is accelerated over charged plates, imparting a charge to the air, which reportedly improves mood, causes bacteria, viruses, and dust to adhere to surfaces instead of becoming airborne, causes beneficial effects on the health of the people who breathe it, and even helps heal injuries. Some or all of these claims might be complete hogwash. One thing is definitely clear, though. Air ionizers create ozone, an oxygen variant that damages your lungs and is the major component in smog, although more useful in the upper atmosphere due it its tendency to neutralize harmful radiation.
The best evidence for the touted benefits of the theory was a study conducted in Bangkok, which showed that ionized air did improve rates of healing from injuries, and did in fact cause airborne bacteria to cease to be airborne, where it could be easily cleaned off the walls and floors that it stuck to. No mood difference was noted in participants. The data size was not large enough to be significant.
On the other hand, even if I assume this is all true, I would first worry about the ozone exposure. Fortunately, it is possible to filter out ozone using carbon-rich paper filters, and the ozone does kill all bacteria (and some viruses) while it is present.
So if this theory was true, the best air sources would be first ionized, then filtered (removing the dust, bacteria, viruses, and ozone), and then accelerated into the room. This also gives me a plan to experiment with this idea.
Get 3 groups of 30 people each. One group is put into a room in which the air is positively charged, filtered, then blown into the room. One group is put into a room in which the air is negatively charged, filtered, and then blown into the room. The last group is the control, and their air is not charged, but merely filtered. The filtering takes place some distance from the room so that it's not apparent which group you're in. The rooms are otherwise identical, and can support sleep, work, games, and eating. We have the group live there a period of time to be decided later. At the end of the period, we evaluate the groups for changes in health and mood, and we also measure bacteria concentrations in the rooms, walls, and floors.
If the theory is true, then I would expect that the positively charged room would be in better health than the control, which would be in better health than the negatively charged room, but that bacteria levels would be highest in the control room.

The Hammock Effect

Discovery News reports that if you want a nap in a hurry, the best way to do so is to grab a hammock and rock yourself to sleep.
Apparently, both the gently sagging support and the rocking motion help you get to sleep faster than our traditional fixed bed.
If this can be consistently replicated, you might want to replace your bed with a hammock. Or, alternatively, we could make slightly curved beds on a mobile frame. Push a button and the mattress is gently shifted side to side in a rocking motion. Rocking you quickly to sleep, and then slowly stopping over the course of a few hours.
We especially need this in America, where studies show that the average American really needs 3 more hours or so of sleep per night than they're actually getting.