What do physical constants mean?

In science classes, we learn some physical constants, such as gravitational constant. Usually, we pay little attention to these numbers. But the magnitudes of these numbers may tell us a lot about the world around us. 

The units of measurements are designed to fit our everyday experience. For example, the unit of length is meter. A meter is a very familiar scale to us. A small child is less than a meter. An adult is more than a meter. 

First we will look at the gravitational constant. It is 6.67* 10^(-11), a very small number. This means that the gravitational force is very small in our daily experience. We won't worry about gravitational force when another person walks toward us. But gravitational force is universal. The movements of the giant bodies, such as stars and planets, are controlled by the gravitational forces. 

Next we will look at the constant for electrical force, the Coulomb constant. It is 9*10^9, a very big number. This means the electric force is very strong. Indeed most biological activities and many daily activities are driven by the electric force. When we turn on the light, or turn on the computer, we use electricity. An electric tool powered by a tiny battery is more powerful than humans. 

Every cell is a tiny battery. The inside of a cell is negatively charged. The outside of a cell is positively charged. Many biological activities are driven by this electric potential. By the way, the earth is a giant battery. The inside of the earth, including the surface, is negatively charged. The atmosphere of the earth is positively charged, by hydrogen ions. The electrical potential between the surface of the earth and the atmosphere is huge. At times of heavy rain, the air becomes more conductive. This is when lightning strikes. The loudness of the thunder indicates the power of electricity. 

Third, we will look at the Boltzmann constant. It is a constant associated with molecules or atoms. It is 1.38*10^(-23). This suggests that an atom is tiny. To gain a sense of the size of atoms, we can also look at another constant we use very often in chemistry, Mole. It is 6*10^23. You can roughly think Mole is the inverse of Boltzmann constant. 

Finally, we will look at the Planck constant. It is 6.6*10^(-34). This is even much smaller than the Boltzmann constant. The Planck constant is mainly associated with electrons and related activities. You can imagine how tiny electrons are. 

Gravitational constant:  6.67* 10^(-11)

Coulomb constant: 9*10^9

Boltzmann constant: 1.38*10^(-23)     (Mole 6*10^23) 

Planck constant: 6.6*10^(-34)