All About Rainbows

Rainbow Diagram

This week I am taking Anneliese's suggestion and using my blog to collect information for my concept map on rainbows. My question is: What makes a rainbow?

To make a rainbow you need sunshine, rain, and colors. The arc and the spectrum of colors are made when rays of light (sunshine) hit spherical raindrops. When the light passes into the raindrop, it refracts (bends). Then the light hits the back of the raindrop, then reflected (turned back), and finally bent again as it passes out of the raindrop. The bending of light at different angles causes the bow effect and the spectrum of light. In a rainbow, the full spectrum of light is there from ultraviolet to infrared, but because our eyes can only pick up a portion of this continum, we only see red, orange, yellow, green, blue, and violet. Also, we will only see rainbows in the morning or afternoon. The sun needs to be at our back and in our line of vision. If the sun is too high, as at noon, it cannot produce the angles needed for us to see a rainbow.

Are There Any Good Viruses?

Herpes Simplex Virus

The video The Future of Food showed us how genetic material is inserted into cells by the use of viruses. My immediate reaction was "yuck," especially when it was mentioned that the viruses used were linked to infectious diseases. My question is: Are there any good viruses?

I found out that viruses are microscopic particles that can infect animals, plants, and bacteria. They consist of DNA or RNA material that is protected by an outer coating of protein. They cannot reproduce on their own , but multiply by attaching themselves to cells and injecting their genetic material inside. Because of viruses' inability to reproduce on their own, most virologists do not consider viruses to be alive. Viruses usually enter the body by the respiratory system or the mouth, where they infect cells of the mucous membranes which lack any protective barriers. Once in the body, the only defense against viruses is the body's own immune system. A healthy immune system will produce enough white blood cells and antibodies that will kill viruses. Some people think that antibiotics can kill viruses, but they have no affect on them. If you have the flu or a cold, you just have to wait it out. So, are there any good viruses? There are a few: Some create beautiful colored tulips, some can be used to create vaccines, and some can be used to inject desirable genes into cells. But the vast majority of viruses is harmful.

A Symbiotic Relationship

Neal Chamberlain's Gallery of Bacterial Pathogens

The video we watched on Thursday explained how GMOs invade cells by using bacteria, and it got me thinking about bacteria in general. I know there are bacteria on my cutting board and there are bacteria in my yogurt, so my question is: Are there good and bad bacteria?

Most of the time we live in a symbiotic relationship with bacteria, which means each organism benefits by living together. At any given time we have about 200 kinds of bacteria living within our bodies. For example, E. coli bacteria has a place to live in our intestines while helping us to digest our food and produce vitamins. We use the lactobacillus acidophillus bacterium to make yogurt from milk. There is also bacteria that is harmful to plants and humans; they invade cells or produce poisonoius toxins. These are called pathogenic bacteria: anthrax, smallpox are a few examples. So the good bacteria live with us harmoniously, while the bad bacteria can make us very sick. Good hygiene, like frequently washing hands, can help prevent bacteria from entering the body.