Many people stereotype(对……刻板印象)the college years as four years’ worth of partying. But that’s not true! Many students use their time to create things. Here are some of their amazingly smart inventions.

A Fire Extinguisher That Uses Sound

Created by Seth Robertson and Viet Tran, engineering students at George Mason University, this sonic fire extinguisher uses low-frequency sound waves to put out fire. At just the right frequency — between 30 and 60Hz，the movement of sound waves creates a vacuum (真空), cutting off the fire’s oxygen supply.

A Marker That Tells You When to Apply Sunscreen How many of you have gone to the beach and forgotten to reapply sunscreen? Two University of Waterloo students—Rachel Pautler and Derek Jouppi—invented Suncayr, a marker that tells you when it’s time to reapply your sunscreen. The ink turns color in the presence of UV light, so when you find a purple mark on your skin, you know it’s time to reapply it.

A Device That Turns a Flat Surface into a Computer

Thanks to Pranav Mistry and Liyan Chang, students at MIT, you may be able to wear a computer in the future. They developed a device called SixthSense. You keep a smartphone in your pocket and wear a little camera/projector around your neck. The smartphone and camera/projector work as a team to sense your finger movements, process information, and project information onto a surface—be it a wall, a table, or the palm of your hand.

A Universal Tape Dispenser

Ever find yourself with a roll of tape in your teeth, using your mouth to tear a piece while attempting not to break a tooth? Cooper Union students Deanna Kovalein and Jessica Marshall created a device called Snip It that fits any tape roll and cuts any type of tape. With the push of a button, the tape gets pressed against the sharp edge, which cuts it.

The rapid growth in skyscrapers worldwide, most of which have large windows, has led to a high demand for window washers. Though the job is well-paid, it is dangerous and accidents are not uncommon. However, if Israel-based start-up Skyline Technologies has its way, the dangerous job may soon be done by Ozmo, an intelligent window cleaning robot, with humans supervising from the safety of the ground.

Much like humans, Ozmo, sitting on platforms hanging from the buildings, uses its arms and brushes to clean the dirt on the glass. A 3D map of the building’s surface programmed into its system allows the robot to skillfully deal with any obstacle it is likely to meet, as it moves up and down the buildings. The robot will self-correct and move around every obstacle that it might have met so as not to break a window.

Unlike present window washers, the robot cleaner does not require soap to clean the glass. Instead, it uses distilled(蒸馏的)water to do the job. Yaron Schwarcz, CEO of Skyline Robotics explains, “We are environmentally friendly.” Ozmo is also expected to be much more efficient than its human counterparts. While it presently takes three cleaners 480 hours each to clean windows of a 40-storey glass building, the robot will be able to do it in 80 hours. However, unlike other robots, Ozmo will not replace human workers, and only make their jobs safer by making them supervisors, who will be controlling the operation from the safety of the ground.

Whether Ozmo, which is still being tested, does as good a job as humans is not clear. If things go well, its creators have much bigger ambitions for Ozmo. Schwarcz told Forbes Magazine, “Window cleaning is just the tip of the iceberg. We plan to replace all tasks that are dangerous and dirty.”

Brushing your teeth twice a day should keep the dentist away. But if a group of scientific researchers have their wish, it will make the rest of your body healthy too. A toothbrush that checks blood sugar and bacteria while you brush is currently in development in the USA. It is one of many gadgets（小器械） proposed by engineers and doctors at the Center for Future Health in New York.

The gadgets seem fanciful, but the basic principles are simple. The gadgets should make it easy for people to detect illness long before it strikes and so seek treatment far earlier than normal. Instead of relying on hi-tech hospitals, the emphasis（重点） is shifted to the home and easy-to-use gadgets. In the long run, the technology may even prevent illness by encouraging us to lead healthier lives.

Intelligent bandages are a good example. Powerful sensors within the bandage could quickly identify tiny amounts of bacteria in a wound and determine what medicine would work best. The cut could then be treated instantly.

The biggest development is melanoma（黑色素瘤） monitor designed to give early warnings of cancer. It could be used to take a picture of your body each week, and then compare it to previous images. If a problem is found, the system would advise you to get a check-up.

If all this sounds worrying, then help is at hand. Experts are also working on a “digital doctor”, complete with a comforting bedside manner. A standard computer would be able to understand your voice and answer questions about your symptoms in plain English and in a way which could calm your nerves.

Stress is no sweat either. A portable communication aid could recognize certain phrases and tones and let you know when you are about to lose your temper. The software would also suggest ways of keeping your cool.

Researchers are still struggling, however, with making the technology cheap and simple enough for the household user. That is going to be the difficult part.