Analytics Education STEM

Mass and Energy – Explained Simply

In this blog, I explain in simple terms, the relationships between mass, weight, and ultimately energy as it relates to anything, including your own body mass, and how all of this can be tied to Einstein’s equation: E=MC^2. By the end of this post, you’ll be able to tell how much energy is stored within you! Don’t worry… it won’t be too wonky and will be a fun read!

Interesting fact: Our mass is the same at a given time, any ANY place from Earth, to the Mooon, to Mars, Jupiter and on and on however our weight is not! Mass is the material composition of atoms and molecules that makes each of us. So, that part is constant (give or take of course) for this exercise. But weight (“heaviness”) is the force of gravity exerted on my body (or yours) or an object. That is, the gravitational force is determined by the mass and the size of the G-force exerted on the mass in that location. Therefore, our weight varies by the planet and even somewhat depending on the exact place on Earth.

Suppose I weigh 200 lbs (pounds) when I’m on Earth as shown on a scale in my bathroom. Great. What’s my mass?

Since US is one of the very few countries in the world that still uses Imperial and the formulas are mostly based on Metric systems, I’ll be swinging between the 2 systems every now and then.

200 lbs = 90.72 kg
w = m*g  (where w = weight in kg-force; m = mass in kg; g = Earth's G-force = 9.8 meters/s^2)

==> m = w/g (w could be expressed as F which is the force due to gravity acting on a body). 

(Then we get the weight in Newtons (N) or kg-m/s^2).

Using metric system then: m = w/g = 9.257 Newtons = 0.944 kg

Using 1kg = 2.20462262 lbs (Metric -> Imperial conversion) = 2.08 lbs (approx.)
  • So, my mass is about 2.08 lbs (0.944 kg) on Earth
  • On Mars, on the Moon, Jupiter, or anywhere in our universe as we know it! My mass is the same.

I’m curious about how much I’d weigh on the Moon. Let’s see, the gravitational force on moon is 1.622 m/second squared (compared to earth’s 9.8). So, Earth’s gravitational force is about 6X that of the Moon’s.

    Therefore, on the Moon, I will weigh about 33 lbs (15 kg)

But if I were to fly to the Sun, there’s no party. In fact, I’d burnt up and vaporized long before I get to worry about my weight, but even if I could, G-force on Sun is about 274 m/s2 or ~ 28X the G-force of earth!

On the Sun, I would weigh 5,600 lbs (2,540 kg) on the Sun...about the weight of a hippopotamus!

Mars’ G-force is 3.71 m/s^2. So, it’s 0.379 of Earth’s G-force (or 38% of Earth’s G-force) or 34.4736 kg.

On Mars, I would weigh 76 lbs (34.5 kg)

What does it tell us? You want to lose weight? Move to Mars, or the Moon! Avoid the Sun because you’ll completely burn up before you worry about weight. Want to gain some weight? Consider Jupiter because you would weigh 2.4x there.

Now that I know my mass and weight and all that jazz, my real quest is to know: HOW MUCH ENERGY LIES WITHIN ME?

To answer that, we have to summon A. Einstein’s theory: E = m*c^2 [Energy = mass times the speed of light squared. E is measured in Joules; mass is measured in kg; c: speed of light in meters/sec]

Think of mass as matter. The equation means that energy and matter are interchangeable. Under certain conditions, matter becomes energy, and energy manifests into matter! It also means a very large amount of energy is contained within a small matter…regardless of the composition of the matter.

What is this ‘energy’? Energy in its pure form is electromagnetic radiation, which travels at a speed of 186,000 miles/s
(300,000 km/s). But let’s talk about energy in more practical terms.

The old rule is that it takes 1 joule of energy to raise an apple by 1 meter (on Earth). Or we can use a modern example such as a light bulb rated at 60 Watts is using 60 joules per second. That’s because Watt is the rate of energy consumption of 1 joule/sec. If we were to lift 60 apples by 1 meter every second then the energy would be equivalent to 60 Watts.

Let’s not forget about what we discussed about mass earlier: mass is the total amount of matter in an object. That’s the m variable in the world’s most famous equation.

Now, let’s think about the energy “stored” inside an apple. An average apple weighs about 6 oz, or 170 g or 0.17 kg

We can calculate its mass (m) then as we did with my body:
m = 0.01735 N = 0.00177 kg

Then we can conclude that the tiny apple (a matter with a small mass) can be converted into a very large amount of energy…to be precise, we find the potential energy from an apple is:

c = 300000 km/s = 300000000 m/s 
c^2 = 9.e+16
m = 0.00177 kg

E = m*c^2 = 159,300,000,000,000 joules!

If that’s from a single apple, how much energy is locked up inside my body?
Using the mass calculation from above, my m=0.944 kg, I am storing a whopping—

E = 0.944 * 90,000,000,000,000,000 = 84,960,000,000,000,000 joules! or almost 85 Quadrillion joules!

That means my body has enough energy stored to light up 85 Quadrillion bulbs (rated @1 watt) LEDS for 1 second!

THAT SOUNDS INCREDIBLE. But let’s try another comparison to really “feel” what this means…

Eiffel Tower in Paris (the ‘City of Lights’) uses 20,000 light bulbs using a total of 22 MW (mega-watts = watts * 1000000) of electricity per day to run. [*]

As calculated above, my total body energy can produce 85 Quadrillion watts or 85 Billion MEGA-Watts of electricity.

Put another way, my body stores enough energy to keep the Eiffel tower lit for over:

84960000000 / 22 (using 22MW per day usage for Eiffel Tower)
= 10,580,323 years!

Let’s read that again: Energy stored in my body can keep Eiffel Tower fully lit for over 10 Million years!

NOTE: Einstein’s equation assumes that to yield that level of efficiency, we would have to convert every one of the atoms in the matter (apple, my body, etc.) into pure-energy…leaving no wasted matter or mass whatsoever. This may not be yet practical but certainly the theoretical potential is proven already.

How can we harness that energy? Nuclear fission is one of the ways. The incredible amount of energy, stored inside the nucleus of an atom, is released by splitting the atom.

Just think about it before you question your potential 🙂

[*] Eiffel tower light usage data source:

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