If you put your history notes under your pillow and sleep on them the night before an exam, will you do any better in the exam? Most of us have hoped this might help. However, knowledge can't go through the pillow into your brain. But that doesn't mean you can't learn while you are asleep.

    Scientists aren't exactly sure how it works, but they have discovered that the brain can learn things during sleeping hours.

    In one experiment, researchers gave German speakers some Dutch words to learn. Then, they divide them into three groups. The researchers played the Dutch words for people in Group 1 while they were asleep, without telling these German speakers what they were doing. The sound was low. So it didn't wake them up, and only the newly introduced words were used.

    Another group listened to the same words while they were awake. The researchers found the people in Group 1 were better able to identify and translate the words later. This was true only for the words that were played while they slept. The third group listened to words when they walked. The walkers didn't have the same success remembering the words as the sleeping group.

    The researchers later found that people had more slow wave(慢波的) brain activity all over the night. They said that more slow waves made people have a better memory for the new words.

    After years of research and testing, the hybrid car was developed and put on the market. It's an interesting and exciting new improvement in today's world as we look for better ways to protect the quality of the air we breathe and save our natural resources.

    The quality of our air is affected by many different things. But one of the largest sources of air pollution is the burning of fossil fuels such as coal and gasoline which is used to power a car's engine. The EPA has set national standards to help control the level of harmful pollutants sent off into the air, and the automobile industry has acted by producing a hybrid car that uses less gas and therefore causes less pollution.

    A hybrid car is a combination of a regular car that runs on gasoline and an electric car that is battery powered. Some people tend to think that since the hybrid car is partially electric, you have to plug it in to charge it. But that's not how it works. The 144 volt battery pack is actually recharged through the energy that is produced when the car's brakes are used. This is referred to as "regenerative braking", because it produces electricity.

    Although the hybrid car still runs on gasoline most of the time, this helps it use less gas than a regular car. When the driver stops at a traffic light, the engine automatically shuts off to save fuel. Then, as soon as the driver puts the car in gear and touches the gas pedal, the engine starts back up.

    Have you ever ridden in a car with someone who ran out of gas? That probably wouldn't happen if you were riding in a hybrid car. It flashes a warning on its computer screen that says, "I am low on gas". When it completely runs out, the warning reads, "YOU ARE NOW OUT OF GAS!" Then the electric power supply kicks in to let the driver travel a few more miles to a gas station.

    I'm sure you all know how important recycling is. Recycling is when you take old things and turn them into new things. It sounds like magic. But it's actually very scientific.