Although they are still widely used in classrooms today, there are a lot of facts about blackboards that people may not know about. The following information can help shed light on it.

Why it is Green

There are several theories put forward to explain this. One theory is that green was chosen because it is easy on the eyes. Since students have to focus on what is written there, manufacturers picked green. Studies have shown that for most people, it is the easiest color on the eyes.

Other colors like yellow or orange can cause strain if stared at too long. Today however they come in various colors. Next to green, black and white are the most popular.

Blackboard / Chalkboard

Other facts about blackboards that need to be clarified are the names. These two are the same thing. Chalkboard is more widely used in the United States. It came into use around 1935.

Composition

The original ones were made of slate. This is grey or black, which is probably where it got the name. In other countries it is usually covered with green color. Modern variants also come in porcelain. The advantage of using this material is its durability. These usually come in white (hence the term whiteboard) but some are still green or black.

Today some are made from coiled plastic sheet. Drawn with rollers, this is scrollable and removes the need for erasing repeatedly. Markers are often sued on them.

Advantages

Studying their composition will also reveal other facts about blackboards. Among them are their benefits. The biggest one is their availability. They are relatively inexpensive. They are easy to set up and put in place. Their varying sizes also make them very convenient.

It has also been pointed out the surface of the chalkboard helps children learn to write. The resistance is just right. White boards on the other hand, are too smooth.

Another benefit is that chalk isn’t hard to clean up. If you get some on your shirt it can be removed easily. Markers can be hard to remove. Chalk also stays a lot longer on the surface.

Disadvantages

The biggest concern about chalkboards is dust. Wiping them off the chalkboard sprays a lot of dust. Those with allergies and respiratory ailments might experience difficulty breathing. When studying facts about blackboards however, you’ll learn that dust free chalks have been invented.

History

The chalkboard was first used in 1801 in America, although it is believed to have been first used in Edinburgh, Scotland. Before that time, teaching was very difficult to do. Teachers would give students a small board made of wood or black grit. The teacher would go over each one at the end of class.

This was very inconvenient. Teachers couldn’t get their points across. Without the chalkboard, it became difficult to express ideas in a visual way. That was why the chalkboard became widely used.

These are some facts about blackboards, which you may have not known. This information can make you appreciate this instrument even more.

The goals of the Human Genome Project are numerous. They encompass a broad spectrum, from broadening scientific knowledge to improving the human condition. The following is an overview.

Mapping the Human Gene

The project was started in 1990. It was initially an American undertaking but soon there were contributions from all over the world. Its primary objective was to determine the DNA sequence in the body.

Another one of its goals was to analyze and map the 25,000 genes in the body. The project was completed ahead of schedule. The only thing that remains now is to analyze the data. This however, can take years to finish.

The goals of the Human Genome Project can be divided into various categories. They are given below. The benefits from the project run the gamut from medicine to forensics.

Medicine

Probably the biggest benefit will be in health. With the gene mapping completed, it’s easier to identify genes associated with diseases. The information gathered from genes can lead to development of needed medication. There is also the strong possibility of identifying the weak genes and replacing them.

Eliminate Environmental Problems

The technology arising from the project can also help the environment. The area of microbial genomics can lead to the development of new energy sources. As one of the goals of the Human Genome Project, it can reduce pollution. Already there is a lot of headway being made when it comes to making pollution detection tools.

By analyzing the genetic sequence of bacteria, ways and means of managing them can be developed. It gives scientists the chance to learn how it causes disease and how to fight it. Gaining deeper knowledge of microbes will also help in managing the environment.

Reducing Health Risks for People

The project can also limit the potential for health risks. A lot of diseases are caused by exposure to pollution and radiation. One of the goals of the Human Genome Project is reduce or eliminate this aspect. Related to this field of study are inherited diseases. By evaluating the genes, it may become possible to keep the ailments from being passed on.

Shedding Light on the Past

By evaluating the genes, more information about human evolution becomes possible. The genes in the body are subject to slight variations and mutations. This information will help scientists discover the physiological makeup of various races. It will also help establish the links between humans and other species in the animal kingdom.

Forensics

Already, DNA is proving invaluable in solving crimes. But it can also be used to settle paternity cases and identify microorganisms that affect livestock. DNA and gene information can make it easier to identify and protect endangered animals.

Agriculture

Crops can be modified to make them more resistant to pestilence. It can also lead to the production of more nutritious food. It can also reduce the need to use pesticides and other chemicals.

The goals of the Human Genome Project encompass virtually all of human existence. There is no question it will take years before they are attained. But the first steps have been taken.

Copper is an industrial metal that has been in use since ancient times. It is a malleable metallic element, which serves various uses. It can be made into thin sheets and can be used to make thin wires since it is quite ductile. It is also a necessary element found in our bodies. And like other elements, it also oxidizes like iron and aluminum.

Understanding Oxidation

Oxidation is a phenomenon that occurs in everyday life. You would notice that a freshly cut apple would turn brown when it is exposed to the air. When oxidation occurs that element will eventually lose electrons while interacting with another element. Another example of this that we regularly see in daily life is the formation of rust on iron.

Effects of Oxidation

When exposed to air, iron forms a flaky reddish outer layer, which we call rust. Rust is the result of this natural process and leads to corrosion. Like the formation of rust on iron, copper will also oxidize as it reacts with oxygen. What forms is copper oxide, which is greenish in color. This green layer forming on top when it oxidizes is known as patina. However, unlike iron, this element does not react with water when exposed to it. Iron on the other hand is sure to form rust when exposed to water.

Another big difference and diametric opposite is that where rust corrodes patina protects. This is also yet another reason why copper is such a valued metal since it is corrosion resistant. Underneath the oxidized layer, patina averts any further corrosion. This is also used as a waterproofing layer on the roofs of old buildings.

An example of oxidation is the one that you will see on the Statue of Liberty. The copper in it has a green colored protective layer, which is only about 0.005 inch thick. This protective layer of patina protects Lady Liberty from being exposed to air and water. Oxygen and water is prevented from reacting through this layer of patina.

Heat Transfer

Heat can still be transferred even if patina forms after this element has oxidized. The idea for this process is pretty much the same as with a convection oven. Oxidized copper is still pretty malleable in spite of the layer of patina on the surface. Since that layer is very thin, it has no effect on this element’s ability to radiate heat. However, take note that you may still see some varying results depending on what method you use to transfer heat.

Daylight savings time refers to the practice in some U.S. states of advancing the time. The practice was implemented in different states to add light to afternoons. The objective for the implementation of this practice is to save electricity that is used in the evening. Daylight savings time is beneficial to the operations of commercial establishments in different states. However, one of the downsides of the practice is that it complicates the business patterns as well as sleep patterns of people. Because of the limitations, some states in the country like Arizona do not implement the practice.

Impact on the Lifestyle of People and Energy Consumption in the State of Arizona

Why does not Arizona observe daylight savings time? The state does not practice daylight savings time because the temperature in the area is hotter than in the other parts of the country. According to reports, many people living in Arizona do not agree the practice to be implemented in the area because it will affect their leisure activities. For instance, there are activities that they cannot do like night entertainment and softball. In addition to this, daylight savings time is not implemented in the state because it can only increase electricity consumption. When they extend the day, it only shows that the time that business establishments and homes use air conditioning and other cooling appliances will be extended.

However, other areas in the state also practice the daylight savings time. One of these is the Navajo Indian Reservation. The reason behind the implementation of this practice is that the reservation occupies some territories in other states that implement the practice like Colorado, New Mexico and Utah.

Other Relevant Information About the Daylight Savings Time

There are various reasons why legislation regarding the practice of the daylight savings time was approved in the U.S. The primary reason is that it is important to save energy consumption in the area. The idea behind the development of this legislation is to save electricity that will be used when homeowners turn their lights at night. It was first approved by the Congress in 1918 during World War I to conserve fuel and energy consumption.

The legislation was dropped after the war but it was reintroduced during World War II. In 1944, the Congress signed legislation saying that the implementation of daylight savings time is up to local governments. This is the reason why some U.S. states including Arizona do not implement the practice.

There are several reasons given by astronomers as to why Pluto is no longer a planet. To better understand it, some background information is essential.

Discovery and Classification

In 1930 Clyde Tombaugh spotted the object over Arizona. It wasn’t entirely unexpected. The movements of the other planets suggested the existence of another one. Even before its discovery, scientists were confident in its existence, which they called Planet X.

The Kuiper Belt

Early on, it was assumed the Solar System consisted of the nine planets, their satellites, comets and the asteroid belt. Over the years, several heavenly bodies were discovered. Eventually scientists discovered the existence of the Kuiper Belt. These objects covered the space from Neptune up to 55 AU (astronomical units).

This discovery is the main reason why Pluto is no longer a planet. Astronomers learned that the planet and its satellite Charon were just one of the 70,000 objects making up this cluster. Their sizes were virtually the same.

Eris

One of those objects was even larger. Named Eris, the object was made of the same material as Pluto. Should it be included as another planet? The problem was tackled at a meeting in Prague in 2006.

Redefining a Planet

At this meeting, astronomers discussed the matter. Some proposed the planets be increased to 12, including Eris and the asteroid Ceres. Other suggested just keeping the status quo. By vote, it was decided that Eris and the other objects in the Kuiper Belt be called dwarf planets.

The reason why Pluto is no longer a planet wasn’t just due to the votes. It was also because planets were redefined. To be called one, it must move in orbit around the Sun. Second, it must have gravity to make a spherical figure. The third is that it must clear the neighborhood.

By this it means the planet must either destroy the smaller objects near it, or push them away. This is the one criterion that Pluto doesn’t meet, so together with Eris they were reclassified as dwarf planets.

Objections

Although the matter has been decided by vote, there are still some objections to it. The most frequent is that cleaning the neighborhood was a concept invented by astronomers.

They point out that it doesn’t apply with other planetary systems in the cosmos. Some believe that the reasons why Pluto is no longer a planet were based on the opinions of astronomers and nothing really solid or scientific.

Others believe that the gravitational pulls should decide if an object is a planet or not. As long as it has enough pull to make a spherical figure, it should be classified as a planet. Even those who believe that the demotion was right don’t like the term dwarf planet. Given that it’s not a planet but an object in the Kuiper Belt, it makes no sense to refer to it as one.

The reasons and arguments for why Pluto is no longer a planet will probably go on for years. But as space enthusiasts point out, it hardly diminishes the fascination that people have with this tiny and remote object.