Why Is the Sea Salty?

 

Why Is the Sea Salty?

Have you ever wondered why the ocean is salty? Have you wondered why lakes might not be salty? Here's a look at what makes the ocean salty and why other bodies of water have a different chemical composition.

The oceans of the world have a fairly stable salinity of about 35 parts per thousand. The main salts include dissolved sodium chloride, magnesium sulfate, potassium nitrate, and sodium bicarbonate. In water, these are sodium, magnesium, and potassium cations, and chloride, sulfate, nitrate, and carbonate anions.

The reason the sea is salty is because it is very old. Gases from volcanoes dissolved in the water, making it acidic. The acids dissolved minerals from lava, producing ions. More recently, ions from eroded rocks entered the ocean as rivers drained into the sea.

While some lakes are very salty (high salinity), some do not taste salty because they contain low amounts of sodium and chloride (table salt) ions. Others are more dilute simply because the water drains toward the sea and is replaced by fresh rainwater or other precipitation.

Oceans have been around a very long time, so some of the salts were added to the water at a time when gases and lava were spewing from increased volcanic activity. The carbon dioxide dissolved in water from the atmosphere forms weak carbonic acid which dissolves minerals. When these minerals dissolve, they form ions, which make the water salty. While water evaporates from the ocean, the salt gets left behind. Also, rivers drain into the oceans, bringing in additional ions from rock that was eroded by rainwater and streams.

The saltiness of the ocean, or its salinity, is fairly stable at about 35 parts per thousand. To give you a sense of how much salt that is, it is estimated that if you took all the salt out of the ocean and spread it over the land, the salt would form a layer more than 500 feet (166 m) deep. You might think the ocean would become increasingly salty over time, but part of the reason it does not is because many of the ions in the ocean are taken in by the organisms that live in the ocean. Another factor may be the formation of new minerals.

What Is an Experiment?

 

What Is an Experiment? The Short Answer

In its simplest form, an experiment is simply the test of a hypothesis. A hypothesis, in turn, is a proposed relationship or explanation of phenomena.

Experiment Basics

The experiment is the foundation of the scientific method, which is a systematic means of exploring the world around you. Although some experiments take place in laboratories, you could perform an experiment anywhere, at any time.

Take a look at the steps of the scientific method:

1. Make observations.
2. Formulate a hypothesis.
3. Design and conduct an experiment to test the hypothesis.
4. Evaluate the results of the experiment.
5. Accept or reject the hypothesis.
6. If necessary, make and test a new hypothesis.

Types of Experiments

• Natural Experiments: A natural experiment also is called a quasi-experiment. A natural experiment involves making a prediction or forming a hypothesis and then gathering data by observing a system. The variables are not controlled in a natural experiment.
• Controlled Experiments: Lab experiments are controlled experiments, although you can perform a controlled experiment outside of a lab setting! In a controlled experiment, you compare an experimental group with a control group. Ideally, these two groups are identical except for one variable, the independent variable.
• Field Experiments: A field experiment may be either a natural experiment or a controlled experiment. It takes place in a real-world setting, rather than under lab conditions. For example, an experiment involving an animal in its natural habitat would be a field experiment.

Variables in an Experiment

Simply put, a variable is anything you can change or control in an experiment. Common examples of variables include temperature, duration of the experiment, composition of a material, amount of light, etc. There are three kinds of variables in an experiment: controlled variables, independent variables and dependent variables.

Controlled variables, sometimes called constant variables are variables that are kept constant or unchanging. For example, if you are doing an experiment measuring the fizz released from different types of soda, you might control the size of the container so that all brands of soda would be in 12-oz cans. If you are performing an experiment on the effect of spraying plants with different chemicals, you would try to maintain the same pressure and maybe the same volume when spraying your plants.

The independent variable is the one factor that you are changing. It is one factor because usually in an experiment you try to change one thing at a time. This makes measurements and interpretation of the data much easier. If you are trying to determine whether heating water allows you to dissolve more sugar in the water then your independent variable is the temperature of the water. This is the variable you are purposely controlling.

The dependent variable is the variable you observe, to see whether it is affected by your independent variable. In the example where you are heating water to see if this affects the amount of sugar you can dissolve, the mass or volume of sugar (whichever you choose to measure) would be your dependent variable.

Chemistry

Chemistry

 

Sitting between biology and physics, the field of chemistry is sometimes called the central science. This branch of science deals not with the most basic elements of reality, such as fundamental particles, or the complex world of living organisms, but the in-between world of atoms, molecules and chemical processes.

Chemistry is the study of matter, analysing its structure, properties and behaviour to see what happens when they change in chemical reactions. As such, it can be considered a branch of physical science, alongside astronomy, physics and earth sciences including geology.

An important area of chemistry is the understanding of atoms and what determines how they react. It turns out reactivity is often largely mediated by the electrons that orbit atoms and the way these are exchanged and shared to create chemical bonds.

Chemistry has now split into many branches. For instance, analytical chemists might measure the traces of compounds in ancient pottery to discern what people were eating thousands of years ago.

Biochemistry is the study of the chemical processes that take place in living organisms, for instance in farming, and on the effect the resulting produce will have on our body’s metabolism.

Organic chemistry, the study of compounds which contain carbon, connects up molecules in new ways to build and analyse an array of materials, from drugs to plastics to flexible electronics. Inorganic chemistry is the study of materials based primarily on elements other than carbon. Inorganic compounds can be pigments, fertilisers, catalysts and more.

Physical chemistry involves looking at chemistry through the lens of physics to study changes in pressure, temperatures and rates of conversion, for example, as substances react.

Chemists help us understand the nature and properties of the world around us and the history of chemistry is replete with discoveries that have furthered this. Antoine Lavoisier paved the way for modern chemistry. He helped give the field structure by developing an ordered language and symbolism. And his understanding of the constituent parts of air, as well as the process of combustion, disproved centuries of incorrect thinking. But there is perhaps no more important chemist than  Dmitri Mendeleev, the Russian who in 1869 wrote down the symbols for all the known chemical elements, arranging them according to their atomic weight. He had created the periodic table, making it possible to predict how any given element would react with another, the compounds it would form and what kind of physical properties it would have.

States of matter

 States of matter

How many states of matter are there?

There are four states of matter commonly found in the universe and on Earth. However, there are many more states of matter that are either man-made or very rarely found either on Earth or in the universe.

Are there 5 states of matter?

Yes, there are five (and more) states of matter. However, only four are commonly found on Earth and in the universe. The most common states of matter are solid, liquid, gas, and plasma. Many other states of matter exist (like degenerate matter, amorphous solids, and supercritical fluids), but they are rarely found in nature.

What are the three states of matter, and what are some examples of each state?

The three main states of matter commonly found naturally on Earth are:

solid - bricks, ice, wood, paper

liquid - milk, water, honey

gas - helium, hydrogen, oxygen, air

The best way to start a discussion on the states of matter is to answer the question, 'What is matter?' Matter is the material that makes up all things in the universe. In its smallest form it is unseeable, but as it combines it grows into atoms that become molecules that become everything in existence.

There are 4 states of matter, meaning matter can exist (or present) in four different ways in the universe. Matter can exist in the following forms:

Solid

Liquid

Gas

Plasma

Solids, liquids, and gases are found in abundance in nature on Earth. The characteristics of solids, liquids, and gases change over three common variables: volume, shape, and energy level of the matter.

Solid State of Matter & Solid Matter Examples

Matter has the least amount of inert energy when in a solid state of matter form. This is because when in solid form, the atoms that make up the object are very tightly packed together and exhibit very little, if any, movement (a molecular microscope can sometimes pick up very slight movement in the atomic level of a solid that is not apparent to the human eye). This tightly packed formation of the solid state of matter equates to high density for solids.

Solids have a definite shape and volume. Solid matter does not have mobile molecules, thus it must stay one shape and size until acted upon by an outside force. Due to this forced stillness in the molecules, a solid will always have a definite (measurable) volume and will maintain its own shape.

Imagine if bricks could change shape and volume at random. That would be disastrous. Which of the practice examples above has a constant shape and volume? Gold. Gold is an example of a metallic solid.

Liquid State of Matter & Liquid Matter Examples

While solids have little to no energy (movement), liquid states of matter have moderate energy, and atoms/molecules within a liquid do move. The word 'fluid' elicits the idea of movement and liquids are certainly fluid. Molecules in liquids are loosely packed together meaning they have moderate density.

In terms of volume, liquids do have a definitive volume, meaning it is possible to measure the volume of a liquid. However, they do not have a definite shape. Liquids take on the shape of whatever vessel they are in.

Physical & Chemical Properties

 Physical & Chemical Properties

Why is density not a chemical property?

Density is not a chemical property; it is a physical property. Density is the measure of the mass of a substance divided by its volume. It is a measurable property that does not change the identity of the substance when determining it.

What are examples of chemical properties?

Chemical properties are the properties of a specific type of matter that occur when the matter goes through chemical changes. Chemical properties/changes result in a change in the composition of the matter. Examples include corrosion and reactivity.

What are examples of physical properties?

Physical properties are characteristics of a certain type of matter that can be observed and/or measured. Physical properties do not affect the chemical composition of the matter. Examples of physical properties include color, mass, texture and density.

Matter is defined as anything that has mass and takes up space. All types of matter have certain properties that are unique to that matter. These properties can be divided into two separate categories: physical properties and chemical properties.

What are the Physical Properties of Matter?

The physical property definition is the properties of matter are generally things that describe the property with visual inspection or taking some kind of measurement. For example, three of the physical properties of matter are length, volume, and mass. There is no change to the chemical composition of a substance when examining its physical properties. Visual observation, a balance, a ruler, or another method of measurement, can be used to determine physical properties. None of the methods used will have any effect on the chemical composition of a substance.

Some additional physical properties examples are:

Color

Texture

Shape

Density

Matter will sometimes undergo physical changes. This happens when a particular type of matter changes state from solid to liquid, liquid to gas, gas to liquid, liquid to solid, or even solid to gas. These phase changes, known as melting, freezing, vaporization, condensation, and sublimation, have no effect on the chemical composition of the substance, therefore, they are not chemical changes. Phase changes, or changes of state, occur when energy is added to or taken from the substance.

For example, an ice cube left on a counter will absorb heat energy from its surroundings and eventually melt to become liquid water. In both the solid state and liquid state, it is still water. No chemical reaction occurred to change the identity of the substance. However, sometimes the physical properties change during a phase change. An ice cube may have a square shape, but when it melts to become a puddle of liquid water, it most definitely takes a different shape. Both shapes are still water.

The physical and chemical properties of matter depend solely on the type of matter in question. Matter can be living or non-living. It can be organic (containing carbon) or inorganic (no carbon present). Essentially, everything is matter; from the tiniest insect to the largest tree. Humans, animals, cars, houses, grass, and food are all types of matter in everyday life.///

Color as a Physical Property

Color is an observable characteristic of matter, therefore, color is a physical property, not a chemical property. Color is observed as the portion of the visible electromagnetic spectrum that is reflected by the substance. If an apple is red, it is because the matter that makes up the apple absorbs all visible colors except red. That makes it appear red to the person observing it. The grass is green because the green wavelengths are reflected and not absorbed.

pH as a Chemical Property

pH is a chemical property that is determined by how many H+ ions are released from a type of matter when it is dissolved in water. Substances that release many free H+ ions are considered to be acidic. Substances that break down in water and produce OH- ions are considered to be bases.

pH is the measure of how many H+ ions are present in terms of concentration. The higher the concentration of H+, the more acidic the solution is. The lower the concentration of H+ and the higher the concentration of OH-, the more basic it is. This makes pH a chemical property because it depends on how a solid or liquid substance interacts with water when mixed together.

The pH scale runs from 0-14. Matter with a pH of 7, like pure water is considered to be neutral. Anything that has a pH of 0 up to 7 is acidic and anything above 7 and up to 14 is basic.

Stomach acid is a strong acid at a pH of about 2. Soaps and detergents are more basic with a pH around 8, depending on the product.

Natural disasters

 

Natural disasters

Natural disasters are large-scale geological or meteorological events that have the potential to cause loss of life or property. These types of disasters include: tornadoes and severe storms, hurricanes and tropical storms, floods, wildfires, earthquakes, drought, avalanche, heat wave, landslide, tsunami, volcanic activity.

 Natural disaster, any calamitous occurrence generated by the effects of natural, rather than human-driven, phenomena that produces great loss of human life or destruction of the natural environment, private property, or public infrastructure. A natural disaster may be caused by weather and climate events or by earthquakes, landslides, and other occurrences that originate at Earth’s surface or within the planet itself. No spot on Earth is immune from a natural disaster; however, certain types of disasters are often limited to or occur more frequently in specific geographic regions.

In modern times, the divide between natural, human-made and human-accelerated disasters is quite difficult to draw. Human choices and activities like architecture, fire, resource management and climate change potentially play a role in causing natural disasters. A natural disaster is the highly harmful impact on a society or community following a natural hazard event. The term "disaster" itself is defined as follows: "Disasters are serious disruptions to the functioning of a community that exceed its capacity to cope using its own resources". Disasters can be caused by natural, man-made and technological hazards, as well as various factors that influence the exposure and vulnerability of a community. A natural disaster is the negative impact following an actual occurrence of natural hazard in the event that it significantly harms a community. An example of the distinction between a natural hazard and a disaster is that an earthquake is the hazard which caused the 1906 San Francisco earthquake disaster. A natural hazard is a natural phenomenon that might have a negative effect on humans and other animals, or the environment. Natural hazard events can be classified into two broad categories: geophysical and biological. Natural hazards can be provoked or affected by anthropogenic processes, e.g. land-use change, drainage and construction.

There are 18 natural hazards included in the National Risk Index of FEMA: avalanche, coastal flooding, cold wave, drought, earthquake, hail, heat wave, tropical cyclone, ice storm, landslide, lightning, riverine flooding, strong wind, tornado, tsunami, volcanic activity, wildfire, winter weather. In addition there are also tornados and dust storms. A natural disaster may cause loss of life, injury or other health impacts, property damage, loss of livelihoods and services, social and economic disruption, or environmental damage.

 

Top 10 Natural Disasters