【推荐1】There are many colors in nature. But do you think that a color has weight? I think you'll say "no". But I'm afraid you are wrong. If you don't believe it, you may do a small experiment.

First, put two objects with the same weight into two boxes. Then cover the boxes. Third, wrap one box with a red piece of paper, the other one with white piece of paper. OK. Now hold the boxes with your hand one by one. It is certain that you will think the red one is a little heavier.

Why do you think so? A scientist found that different colors have different weights in man's mind. That is to say, every color has its own weight in our mind.

The scientist told us that colors also have smell. Can you smell the color? Of course not. Then why did the scientist say so? That is because every color stands for kind of light with a certain wavelength（波长）. It reaches our brain through sense organs.

According to this discovery scientists say that people accept the colors they like, and refuse the colors they hate. So your body and mind will be healthy by using the colors you like. Or you'll be nervous or even get ill. For example, you like blue and hate red. If you stay in a room with red windows, wallpaper and furniture for two hours, you'll feel you have been there for four hours. But if the room is blue, you'll feel you have been there for only an hour. And if a person walks out of a blue room and into a red room, his temperature will rise. That means our body temperature will change with different colors.

Why should mankind explore space? Why should money, time and effort be spent exploring and researching something with so few apparent benefits? Why should resources be spent on space instead of on conditions and people on Earth? These are questions that, understandably, are very often asked.

Perhaps the best answer lies in our genetic makeup as human beings. What drove our ancestors to move from the trees into the plains, and on into all possible areas and environments? With the wide spread of a species, human beings can get high chance of survival. Perhaps the best reason for exploring space is this genetic tendency to expand wherever possible.

Nearly every successful civilization has explored, because by doing so, any dangers in surrounding areas can be identified and prepared for. Without knowledge, we may be completely destroyed by the danger. With knowledge, we can lessen its effects.

Exploration also allows minerals and other potential resources to be found. Even if we have no need of them right now, they will perhaps be useful later. Resources may be more than physical possessions. Knowledge or techniques have been acquired through exploration. The techniques may have medical applications which can improve the length or quality of our lives. We have already benefited from other spinoffs including improvements in earthquake prediction, in satellites for weather forecasting and in communications systems. Even nonstick pans and mirrored sunglasses are byproducts of technological developments in the space.

While many resources are spent on what seems a small return, the exploration of space allows creative, brave and intelligent members of our species to focus on what may serve to save us. While space may hold many wonders and explanations of how the universe was formed or how it works, it also holds dangers. The danger exists, but knowledge can help human beings to survive. Without the ability to reach out across space, the chance to save ourselves might not exist.

While Earth is the only planet known to support life, surely the adaptive ability of humans would allow us to live on other planets. It is true that the lifestyle would be different, but human life and cultures have adapted in the past and surely could in the future.