While wandering near a creek, have you ever seen bugs walking on the surface of the water? Have you felt any resistance when you hit the surface of the sea with your palm? Have you ever thought about what causes these to happen?

The two examples of events given above happen to be related to “surface tension.” This situation is described as the force per distance unit that is generated in the opposite direction of the direction of expansion between two different surfaces. It can take place in between two different liquid layers, as well as among liquid-gas and liquid-solid layers. For example, the surface tension of a liquid forms in the transitional region where liquid and gas molecules make contact. The source of this force generated on the liquid’s surface is the intermolecular attractions that hold the liquid molecules together. Each molecule in the liquid is pulled via opposite but equal forces by neighboring molecules, thus no single force is acting on the molecules. However, the molecules on the surface are only surrounded by one side, therefore they are pulled inwards with a net force (Figure 1), causing a tension similar to an inflated balloon on the surface of the liquid.

When we look carefully to a stagnant pool of water in a container, the surface of the water seems to be covered with a thin layer of film, resembling a stretched membrane. In order for a substance to enter or leave the body of water successfully, it must puncture this membrane. In other words it has to overcome this intermolecular force. If a steel blade is laid horizontally on the surface of the water slowly, it floats despite that it is made of denser steel because it cannot overcome this surface tension. Surface tension is the principle responsible for the trampoline-like behavior of liquid surfaces. Many insect species created for aqueous habitats can maintain their lives on the water via their adapted leg parts. The best example of this is the water strider. This insect lives on water by taking advantage of water surface tension. Though the surface tension principle is a requirement to be on the water, it is also necessary that the strider not to stick to the surface. Therefore, this insect is also equipped with a paddle made of waxy hairs at the end of their legs (Figure 2).

Forces of cohesion and adhesion

The intermolecular force of a liquid among the same kind of molecules is called the “cohesion force,” and intermolecular attraction between different types of liquid molecules is called the “adhesion force.” These forces of adhesion and cohesion determine the behavior of a liquid in a container. If some mercury is put in a glass tube, because the cohesive forces among the mercury atoms is greater than the adhesive forces in between the glass container and the mercury, the mercury assumes a convex shape. Here, mercury has a tendency to reduce its contact with the glass and does not wet it. In contrast to mercury, when water is put inside the tube, the surface layer between the water and air takes an inward concave shape. This is caused by the greater adhesion force between the water and glass compared to the intermolecular cohesion forces of water. Water wets the glass since it has a tendency to spread towards the greatest surface possible (Figure 3).

When there is a thin layer of water or tea left in between a tea glass and its plate, the adhesion force glues the glass and plate together. Since the adhesion force is greater than the weight of the plate, the glass cup can be lifted together with the plate. Contact lenses also stay in position on the eyes without falling through the help of adhesion forces. Tears strongly pull both cornea and the contact lens together, holding it in place.

The capillary effect

A liquid inside a thin vertical tube is pulled upwards by the inner surface of the tube until the adhesion force becomes balanced with the liquid weight. This event is called the capillary effect or capillarity. Liquids naturally rise in narrow channels if there is sufficient adhesion force. This effect is enhanced in narrow tubes due to the smaller volume of the liquid, but reduced in wider tubes because of gravity. Therefore, there is an inverse ratio between the channel diameter and liquid height in capillarity.

The reason a sponge absorbs water effectively is the easy rise of water in the capillary openings of the sponge. In a similar fashion, there are small openings found in paper napkins and towels. When a napkin makes contact with a wet surface, water is pulled inside the small openings with capillary action, thus removing the water from the surface. This is because the adhesion force in between the napkin tissue and water is greater than the cohesion force of the water molecules. This principle is also utilized while getting blood samples with capillary tubes. In addition, the removal of continuously excreted tears by the capillary ocular ducts that extend into the nasal cavity is another example of this wise law.

Capillary action is also important for the transportation of water molecules from humid parts towards drier areas in soil, providing for the spread of water. The same principle is also vital to nourishment of trees. Every part of a tree encompasses capillary channels, all the way from the tips of the roots to very ends of the branches. Water molecules are transported to the leaves against gravity when they enter the tips of these capillary channels at the roots. Even though the adhesion forces between the water molecules and the root’s tissues win the war against gravity, at a certain height, this force becomes equal to the gravitational pull, thus not allowing water molecules to climb higher. This is the ultimate height a tree reaches. Capillarity also affects internal water pressure of a tree, leaf size, photosynthesis, and other factors. This is why the leaves of a tree are usually bigger on lower branches compared to higher ones (Figure 4).

The surface tension of water is the highest among the known values of other liquids and this has very significant biological effects. If the surface tension of water was to be lower, like other liquids, it would not be able reach the higher parts of plants through capillary action, thus preventing the survival of taller plants. The vegetation waits patiently as nourishment is delivered to its roots. Water has been assigned a vital role in this service.

The water-dependent survival of plants is made possible through the capillarity and surface tension. Could this amazing phenomenon, in which the capillarity is on duty to water the leaves on the highest branches of the tallest trees to ensure the maintenance of life, take place via blind atomic interactions or accidental occurrences?

How do liquid droplets get their shape?

Objects with a wider surface will have a greater surface tension. Since the force of surface tension, acting on per unit distance, is equal to the surface energy per surface area, a wider surface requires greater accumulation of energy on the surface. All the matter in the universe tends to stay at a lowered energy level. Therefore, it is ideal for objects to reduce their surface area. When the surface area to volume ratio of the known geometric shapes is investigated, the smallest ratio is found to belong to a sphere. A small value of this ratio means the most reduced surface area per volume. Among enclosed containers of equal volume, a sphere is also the one with the smallest surface area. When two equal volume watermelons of spherical and cubical shape are peeled, the spherical one will produce the least amount of rinds.

Because of the reasons mentioned above, liquids take a droplet shape immediately when they fall, reducing their surface area. That is why a water droplet dripping from a faucet, a falling rain drop, and a droplet on a leaf are all in the shape of a sphere (Figure 5). It is the same principle that makes planets and other heavenly bodies resemble a globular form. This indeed points to an Almighty Power who plans the motions, positions, and assignments of all the objects, from particles to giants, managing and dispatching them as The Self-Existent One holding everything together.

Factors affecting surface tension

Temperature increase is directly proportional to a decrease in the surface tension in most liquids. When the temperature of a liquid rises, so does the kinetic energy of the particles in it, making these particles move faster. This leads to a weakened intermolecular attraction that binds molecules together. Since this change affects the particles at the surface, it decreases the tension. Improved soaking of hands and laundry can be achieved with warm water during cleaning because heat reduces the surface tension. This helps with better cleaning results in a shorter amount of time.

In a similar fashion, soap and detergents also reduce the surface tension of water. If a small soap bubble is placed on a water droplet, the droplet spreads away instantly. This indeed tells us that the soap bubble reduces surface tension.

If a substance dissolves in a pure material, surface tension is found to change depending on the solute and the solvent structure. For example, salt decreases the surface tension of water. Salt weakens the intermolecular bonds of the water molecules, and therefore reduces the cohesion and surface tension. That’s why sea waves foam when they hit shore.

Can surface tension be associated with the ability of unconscious and primitive atoms as the principle behind many functions and tasks in the lives of plants and animals? Do such wondrous events happen by chance? Isn’t this principle such a blessing of the One who easily provides what is necessary to all living things, nourishing them in time according to their needs?

Why is this surface area so large? What could the wisdom behind it be? Tiny endoplasmic canals play a role in inner cell transportation and distribution of matter. ER is the organized industry district in the cell. Most of the factories of molecules produced by chemical reactions are found here. ER is the production spot in the cells of proteins and hormones. Consequently, a broad surface area is very necessary and important.

Different degrees (pH) of acid are necessary for each reaction. However, because the acid necessary for one reaction can negatively affect the other reactions, thousands of opposite, intricate and different reactions take place. For this reason, membrane surface areas need to be wide. Sometimes hundreds of protein molecules are produced in just a second in a cell. The rapid and flawless lining up side-by-side of tens, hundreds or thousands of amino acids can only be achieved with a knowledge and power that surpasses these very small structures.

Wrapping the inside of the cell like a web and forming a buffer against mechanical effects, ER is responsible for establishing the flexibility and soundness of the cell. In muscle cells, ER takes the name Sarcoplasmic Reticulum (SR), which has a very important duty in the contraction of muscles. The size of the surface area of SR in the muscles of the structural frame is proportionate to the speed of muscle contraction. Consequently, there is more SR in muscle cells where there is rapid contraction. SR also serves as a calcium depot in muscle cells. Normally calcium is a deadly poison for the cell, and for this reason it is kept out of the cell. The concentration of calcium outside the cell is 10,000 times more than it is inside the cell. However, SR stores calcium in the cell in its own body. Thus, it both prevents the cell from being harmed and it provides the necessary calcium for contraction.

ER has the duty of eliminating the poison in the liver cells from the body by means of gall. For example, jaundice-causing bilirubin is a deadly poison for the brain especially in newborn babies. If jaundice is not treated, motor loss (paralysis) and intelligence loss can result from brain damage. Bilirubin and glucuronic acid combine by means of some enzymes on the surface of ER in the liver and are thrown into the gall bladder. In this way ER plays an important role in making foreign matter harmless and in reducing the side affects of medications to a minimum. Babies’ sensitivity to some medications during the first three months of life is due to ER’s not yet being developed enough to eliminate their harmful effects.

If it is taken into consideration that all of these mechanisms exist in human, animal and plant cells, it can be clearly seen that a broad and complex structure in such a small volume and its many functions can only have been placed there by the All-Powerful whose knowledge, wisdom, artistry, will and power permeate every moment and every spot.

Celaloglu is a freelance writer from Turkey with a degree in biology.

A small-scale blueprint of the universe, the human body is a miraculous work of art that manifests the beautiful divine names and attributes of God Almighty. A human body is made up of a set of hierarchically organized components: an organ system, organs, tissues, cells, organelles, macromolecules, molecules, atoms, neutrons, protons, electrons, and subatomic particles. In this biological organization, it is striking to observe a proportionately allocated space between components on each level for their efficient functioning. The size of human body would be reduced if these spaces between organs, tissues, cells, and atoms could be removed, and the entire human body would not be bigger than a small ball.

The structure of an atom explains a lot concerning the real size of our body, which is filled with space. An atom is comprised of protons and neutrons in its nucleus, around which electrons continuously orbit. The mass of neutrons is almost equal to the mass of protons. Electrons, however, are 1,837 times smaller in mass than neutrons and protons. That is, almost 99.95% of the atom’s mass is in its nucleus. The mass of electrons is almost non-existent compared to the nucleus.

Both the universe and our body are filled with more hydrogen than any other atom. In each one billion atom in our body, six hundred thirty million are hydrogen atoms. In a hydrogen atom, electrons rotate only 0.53 nm (one billionth of a meter) away from the nucleus, which makes the atom’s volume to be around 6.10^-28m³, whereas the volume of the proton is 7.10^-45m³, i.e., the nucleus is only as big as one hundred quadrillionth (100.10¹⁵) of the atom’s total volume. In other words, while the nucleus comprises almost the entire mass of the atom, its volume is of no considerable size. The density of protons in the nucleus is 2,3.10¹⁷ kg/m^{3 (where does the period go here??)}, which means that there is around a hundred trillion tons of matter in only one cubic meter. If we could gather all neutrons and protons in one spot, a man who is 69 kg would be only 3.10^-7 mm³ in volume. That is, the volume the total substance of our body takes up is around one ten millionth of a cubic millimeter. The human body, which is constructed of atoms with electrons rotating on an orbit quite far away from the nucleus, is in a way no different than an “inflated space.” For a comparison, the space between the earth and the sun can be filled with as many as 107 suns, whereas 450 thousand protons are needed to fill up the distance between the proton and electron in a hydrogen atom.

The subatomic world is even more amazing. In subatomic particles are found six types of quarks. A quark is considered a fundamental constituent of matter. Combinations of quarks in different shapes and numbers result in subatomic particles, the further combinations of which produce atoms, molecules, and so on. Quarks are considered to be without mass; that is to say, they are nothing else but energy. Humans have mass, but this mass consists of quarks that are without mass.

This incredibly vast space between atoms that make up matter teaches us that our true value does not lie in our physical structure, but in the artworks of no comparison designed by the Divine as manifestations of His most beautiful names. Thus, we, who are so little in material substance, should seek other gateways in the depth of our souls and attain some value with proximity to the Divine.

We may never have revolted against God Almighty in our entire life; yet still our material minority should free us from all kinds of pride and conceit. Our physical structure is very much like the number “zero,” for 0 is also nothing, and it is drawn by inflating.

One of the most important reasons for the last two world wars was the sharing of energy sources. 60 years on from the last world war, the world is now very close to confronting the same problem. There has been an enormous rise in energy demand since the middle of the last century. This increase has resulted from both rapid industrial development and population growth. As shown in Figure 1 and 2, the world population is 4.8 times greater, and the total energy requirement has increased more than 30 fold from between 1850 and 2000. Many studies have demonstrated that while global demand increases by at least 2-3% per year, the current oil fields are depleting at an average of 3-5% per year. If this demand continues at this rate, we will reach a point of crisis in oil sometime after 2010, and the same will be true for natural gas somewhat later, between 2020 and 2030 [1, 3]. The basic energy source of the world, hydrogen, is a new hope for solving the energy problem. It is likely that this century will be the century of the fuel cell. This technology uses hydrogen as fuel, and offers the prospect of supplying the world with clean, sustainable electrical power.

Hydrogen, which is the simplest element in space, was discovered in the 16th century and its inflammable property was understood in the 18th century. Ninety percent of the known universe consists of this simple element. Hydrogen is colorless, odorless, nonpoisonous, and 14.4 times lighter than air. In its liquid phase it has a temperature of -252.77 °C. It is the fuel of the sun and other stars, hence the main energy source of the universe. Hydrogen is not found as a free element in nature, but rather it is found as a compound, particularly as water. Hydrogen has the largest energy amount per unit mass among known fuels. The energy of 1 kg of hydrogen equals 2.1 kg of natural gas and 2.8 kg gasoline. However, its volume per unit energy is higher. It is 1.33 times more efficient compared with fossil fuels as an energy source. When hydrogen is used to produce heat or propulsion, only liquid water or water vapor emerge, making it an extremely clean energy source.

Hydrogen can be used with fuel cells to produce electricity. At the present time, the cost of this method is 3 times more expensive when compared to other fuels. Fuel cells use hydrogen, or hydrogen containing compounds to produce electrical energy and heat. A fuel cell has no moving parts and makes no noise when operating. A single fuel cell contains three layers, as shown in Figure 3. These are the anode-electrode layer, the membrane layer, and the cathode-electrode layer.

There are three types of fuel cells; Polymer Electrolyte Membrane (PEM), Direct Methanol Fuel Cell (DMFC), and Solid Oxide Fuel Cell (SOFC), each named after the material used as fuel. The PEM fuel cell is fueled by pure hydrogen. In the anode, hydrogen is split into its basic elements, a proton and an electron. While the proton migrates through the membrane of the fuel cell, the electron travels around the membrane and goes to the cathode, creating an electrical current. In the cathode-hydrogen proton the electron reacts with oxygen to form water, which is rejected as waste. The basic system is the same for the DMFC and the SOFC fuel cells. The DMFC is fueled by a mixture of methanol and water. Before reaching the anode electrode, the methanol is split into CO²and hydrogen. The SOFC fuel cell can use different kinds of fuels that contain methane and hydrogen. All the reactions are shown in Table 1. One fuel cell can produce 0.6 of a volt. To get enough power, several fuel cells are piled in a stack. The space between fuel cells is filled with gas that helps to distribute the hydrogen and oxygen gas to the membranes.

Although hydrogen energy is a new source, the production of hydrogen is not a new concept. Every year, 500 billion m³ of hydrogen is produced, stored, transported, and utilized in the world. Initially, hydrogen was used for the production of ammonia, but today hydrogen utilization has expanded tremendously to incorporate applications in chemical and petroleum refining, metallurgy, the hydrogenation of edible fats and oils, space and weather programs, fuel cells, and the manufacture of high quality electronic components. The most important consumer is in the petroleum- chemistry industry.

Hydrogen can be obtained by using different methods. Hydrogen can be produced from electricity, using electrolysis to split water into hydrogen and oxygen. Reforming is another method that produces hydrogen. In this method, hydrogen is extracted from a gas with a high concentration of methane, such as natural gas. This process uses hot steam to obtain hydrogen from the methane. When methane gas is mixed with hot water vapor, the gas is split into carbon monoxide and hydrogen.

Although hydrogen can be stored as a gas or liquid, storing and handling hydrogen is difficult as compared to gasoline. While gasoline is a liquid, hydrogen is a gas. At atmospheric pressure at sea level (pressure at sea level is 1.0 atm = 1.01325 bars), hydrogen has a volume 3,100 times greater than gasoline. To decrease the volume of the hydrogen, pressure is used. Hydrogen can be stored under pressure up to 700 bars. At this pressure, hydrogen has a volume 6.4 times greater than that of gasoline.

Another method for storing hydrogen is in the liquid phase. In this phase, hydrogen has a volume 3.6 times greater than gasoline. Liquid hydrogen can be stored under high pressure in steel tubes. Hydrogen should be cooled to -252.77 °C to become liquid. The cooling process requires energy. 25% of hydrogen energy is used for the cooling process. The largest liquid hydrogen tank is at the Kennedy Space Center in Florida. It contains up to 3,400 m³ liquid hydrogen.

Hydrogen can also be stored in metal hydrides. When cooling is applied, the hydrogen atoms diffuse inside the metal hydrides. To release the hydrogen, the reverse process, heating, is needed. Due to the large storage necessary, aluminum and boron hydrides have been used extensively over the last 10 years. In particular, boron hydrides are important as they can be used in liquid conditions. Metal hydride storage is very safe because of the low pressure and the fact that there is little free hydrogen inside the storage tank. Another advantage of this way of storing is that metal hydrides hold hydrogen at very low volumes.

It seems that hydrogen may be the major energy source in the future. Eventually, it will be used to supply the energy needed in the economy, being used for transportation, central and distributed electric power, and combined heat and power for buildings, and industrial processes. However, hydrogen technology is currently in the pre-production stage of development. Hydrogen energy is not cheap when compared to other energy sources at this time. There are some challenges that need to be overcome, such as producing, storing, and using hydrogen efficiently before we use hydrogen instead of fossil fuels. However, hydrogen is the key to solving the energy problems of the world. Hydrogen is available in every country, everywhere. Using hydrogen as an energy source will prevent many conflicts between countries. This energy source will help address concerns about energy security, global climate change, and air quality. It seems that the views of Jules Verne, quoted at the beginning of this article, will be realized one day in the future. And people will thank God not only for water, but also for the hydrogen in it.

References

1. “Energy Wars” by David Chapman – a director of Bullion Management Services the manager of the Millennium BullionFund (www.bmsinc.ca).

2. Cook B., ‘An Introduction to Fuel Cells and Hydrogen Technology’, Heliocentris, 2001.

3. www.un.org

4. www.census.gov

5. www.worldenergy.org

6. www.fuelstore.com

7. www.minihydrogen.dk