Have you ever enjoyed a trip to a zoo, but wondered whether it is acceptable for humans to keep so many treasured animals in cages. You are not alone. Many people concerned about the fate of zoo animals and feel conflicted about the very existence of zoos. However, there is no reason to worry.

Most zoos around the world provide the highest level of care and cleanliness for their animal residents. In fact, animals in zoos often experience far healthier lives than they would in the wild due to the access to medical care.

Zoos provide opportunities for people of all ages to view and connect with animal life that they would otherwise not encounter. By interacting with wild life, people can gain a greater appreciation for the animals of the world. Zoos offer educational experiences through which people can learn why it is so important to protect and maintain the diversity of animal life on Earth.

Zoos also function as places where these often rare or endangered animals can be studied. By keeping and raising animals in cages, extensive research can be conducted on the animals to help scientists understand them. This scientific understanding, in turn, contributes to conservation efforts around the world. Because zoos are a safe place for animals to be observed, scientists are able to make important discoveries about their lives.

While it is true that not all zoos are as well maintained and equipped, there is growing international pressure for universal regulations that will ensure the monitoring of all public zoos. This type of legal support will allow the world’s zoos to continue their important research programs, many of which are adjusted toward breeding programs designed to make more endangered species come in. Breeding programs are essential to continue certain species which are nearly wiped out from the wild, and zoos are the ideal place for these programs to promote the increase of the animals. In this manner, zoos contribute to restoring balance in the wilderness by giving endangered species a second-chance at survival.

If you visit a top-ranking zoo, you will enjoy viewing animals in a habitat designed to support their health. You can rest assured that by supporting such zoos as a visitor, you are also supporting valuable science and conservation efforts. Your interactions with the animals and exhibits might educate you further about creatures in parts of the world you haven’t been exposed to.

When people are inspired, they tend to take action more readily, and zoos are an inspiring example of this truth. Zoos provide an unforgettable experience in appreciating animal life and take concrete action towards advocating for their future.

Have you ever heard of invisible ink? You may have seen it in movies. When light is shone on the paper which invisible ink is written on, you can read it!

As magical as this seems, the change in color is due to science. The ink is absorbing higher energy light and giving lower energy light. This reaction is an example of fluorescence（荧光）.

Light is a very broad term that describes a range of electromagnetic rays, including gamma rays, infrared light（红外光）and ultraviolet light. One part of the electromagnetic visible light is the colors that we can see with the human eye. These rays travel in curvy lines and each type of the ray is characterized by a different wave pattern. For example, Gamma rays have a shorter wavelength than infrared light. Shorter wavelength is connected with higher energy, so gamma rays also have more energy than infrared light.

Corals（珊瑚）are animals that live underwater. And the corals in the Red Sea exhibit fluorescence. Why is this happening? Scientists have shown that fluorescent objects absorb higher energy light and release lower energy light. Since the corals of the Red Sea are deep in the water where there is very little visible light, scientists theorize that these corals absorb ultraviolet light and produce visible light. They have special photo proteins, which enable them to change invisible light to visible light.

Fluorescence is not just used to create pretty colors. Corals have developed photo proteins for a biological reason. The visible light is used by algae（海藻）, which are eaten by the coral, to make food through photosynthesis（光合作用）. The visual character of these photo proteins could also be used for biomedical research. They can highlight cells and cell structures under a microscope.

Isn't it amazing that a simple organism that we don't think very much of is not only grand but could also have so many potential uses in medical research!