Looking Up the Values of Constants

In addition to performing calculations, Google also knows a variety of mathematical and scientific constants, such as pi, Avogadro's Number, and Planck's Constant. It also knows the radius of the Earth, the mass of the sun, the speed of light, the gravitational constant, and a lot more.

Let's check this out. Not sure what the value of pi is? Enter pi and Google returns 3.14159265, as shown in Figure 14.5. How about the speed of light? Enter speed of light, and Google returns 299,792,458 m/s, as shown in Figure 14.6. What about the radius of the Earth? Enter radius of earth, and Google returns 6378.1 kilometers, as shown in Figure 14.7.

Figure 14.5. The value of pi.

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Figure 14.6. The speed of light.

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Figure 14.7. The radius of the Earth.

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Now let's get fancy. Try dividing the radius of the Earth by pi. Enter (radius of earth) / pi; Google's answer is 2030.21229 kilometers, as shown in Figure 14.8. Or how about multiplying the radius of the Earth by the speed of light and then dividing the answer by Avogadro's Number? I'm not sure why you'd want to do this, but the query looks like this: (radius of earth) * (speed of light) / (avogadro's number). (The answer, shown in Figure 14.9, is 3.17512652 x 10-09 m2/s.)

Figure 14.8. The radius of the Earth divided by pi.

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Figure 14.9. The radius of the Earth times the speed of light divided by Avogadro's Number.

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And what constants does Google know? Here's a short list, with shorthand entries in parentheses:

• Atomic mass units (amu)

• Astronomical Unit (au)

• Avogadro's Number

• Boltzmann Constant (k)

• Electric Constant (epsilon_0)

• Electron mass (m_e)

• Electron volt (eV)

• Elementary charge

• Euler's Constant

• Faraday Constant

• Fine-structure Constant

• Gravitational Constant (G)

• Magnetic flux quantum

• Mass of moon (m_moon)

• Mass of planet (m_planet, as in m_earth)

• Mass of sun (m_sun)

• Molar Gas Constant (R)

• Permeability of free space

• Pi

• Planck's Constant (h)

• Proton mass (m_p)

• Radius of moon (r_moon)

• Radius of planet (r_planet, as is r_mars)

• Radius of sun (r_sun)

• Rydberg Constant

• Speed of light (c)

• Speed of sound

• Stefan-Boltzmann Constant

For example, if you wanted to find the speed of light, you could enter speed of light, or you could just enter a capital C. Google knows the value both ways.