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Where did the Earth's atmosphere come from?

According to NASA, Earth's earliest atmosphere was likely composed of only hydrogen and helium, two of the most abundant substances in the universe. These gases also composed the gassy disk around the Sun from which the Earth and all surrounding planets were formed. When the atmosphere first formed, Earth was extremely hot and inhospitable to the life that currently exists on it. Hydrogen and helium molecules hovering over Earth's surface eventually took on such velocity that they escaped the gravitational pull of Earth and drifted into space. This process resulted in the formation o..

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What are the negative effects of weathering?

Weathering damages national monuments, historic buildings and landmarks. It causes rust, cracks, crumbling and other imperfections to stone, marble, wood and other materials.\nMechanical weathering breaks rocks into smaller pieces. Temperature change causes thermal stress on rocks as they expand and contract, which leads to crumbling and cracks forming. Water collects inside these cracks and then freezes, causing further damage. Likewise, saltwater crystallizes and creates more fractures. Plants grow through the cracks and animals dig in the soil, further breaking apart and dislodging structur..

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How do you make electricity for a science fair project using a fruit?

Prepare the fruitSqueeze the fruit lightly on all sides with your hand. Be careful not to put too much pressure on the fruit or break its skin. The fruit should be softened and juicy.Insert the nailsInsert both the copper and the zinc nails into the fruit, about 2 inches apart from each other. Make sure the ends of the nails are in the center of the fruit but not touching. The nails should not pierce through the other side of the fruit.Light the LEDRemove any insulation that may be covering the LED leads. You need to uncover enough of the leads to wrap around the nails. Take one of the exposed..

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What makes algae grow?

A broad spectrum of organisms fall under the classification of algae including microscopic single-celled organisms such as diatoms, as well as giant, complex organisms like seaweed. Certain kinds of seaweed, such as the eastern Pacific kelp, can grow to several hundred feet in size. Although all algae nourish themselves via photosynthesis, they reproduce in a variety of ways, both sexual and asexual.\nIn asexual reproduction, an organism uses only its own genetic material to reproduce. Many of the single-celled algae reproduce via binary fission, meaning an alga simply splits in two, yielding ..

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What does Ohm

Electric current is measured in amperes, while voltage is measured in volts, and the resistance of a conductor is measured in ohms. Resistance is the property of a substance or an object to oppose the flow of electric current through it, and resistance will always remain a constant in its relationship with current and voltage. A substance exhibiting a high value of resistance, such as quartz, will oppose the flow of electrical current through it more than one with a lower resistance value, such as copper. Ohm's law is named after Georg Ohm, the German physicist who first published it in i..

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What is the structure of oleic acid?

Oleic acid is classified as a monounsaturated omega-9 fatty acid. It occurs naturally in animal and vegetal fats. It is part of the human diet, and it is the most abundant constituent of human adipose tissue. It also plays a biological role as an insect pheromone in ants and bees, being released at the time of death in order to trigger the instinct of worker insects to remove the corpse from the hive.

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What are the risks of an unbalanced diet?

Obesity is the leading risk of an unbalanced diet, and it is associated with numerous comorbid health conditions, according to the World Health Organization. Obesity results from a high energy diet, often filled with an excessive amount of calories from sugar, starches and fat, combined with reduced energy expenditure. Diabetes is a serious medical condition that is often caused by dietary imbalance and can lead to other serious conditions, such as heart disease, kidney disease and stroke.\nThe Nation explains that an unbalanced diet often results in malnutrition due to deficiencies in the var..

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What are three examples of chemical changes?

When a chemical change takes place, new products are formed as a result of chemical reactions. At the molecular level, bonds between atoms and molecules are broken and new bonds are formed. This results in the formation of new compounds.\nMost chemical changes are irreversible. However, there are some chemical changes that are reversible. The formation of ammonia from hydrogen and nitrogen is an example of a reversible chemical change. Some chemical changes are rapid, such as the burning of a magnesium ribbon. Others are slow, such as the rusting of iron.

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How do glow sticks work?

A typical glow stick consists of a thick, flexible plastic tube filled with the oxalate ester and dye solution. In the center of the tube is a fragile capsule containing the hydrogen peroxide. When the tube is bent, this capsule breaks, and the two liquids combine and begin to react.\nOne of the chemicals formed by this reaction is a peroxyacid ester, a particularly unstable compound. This compound decomposes, passing through multiple phases and releasing energy into the surrounding molecules. When this energy strikes the dye molecules, the electrons in those molecules briefly jump to a higher..

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How many people does NASA employ?

NASA was founded in 1958, one year after the launch of the Soviet satellite Sputnik. Since then, the organization has directed American exploration and research in space. NASA landed the first humans on the moon in 1969, and there are NASA astronauts on the national space station as of 2015, notes the organization's website. NASA also uses satellites and space probes to explore the solar system.

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