E = mc 2

E = mc 2 is everywhere!

E = mc 2 Energy (in joules) = Mass (in kilograms) X = Mass (in kilograms) X The Speed of Light Squared (in meters squared per second squared)

The big question??? How much energy will one liter of water yield if it is converted entirely into energy?

But Chemistry says matter cannot be created nor be destroyed??? No it’s Not! Matter and Energy are two forms of the same thing! Neither can be destroyed but, under special circumstances, either can be turned into the other Lots of energy goes into making even a small mass and it can also be got back in some form. E = mc 2 tells you exactly how much energy a given amount of mass contains.

The speed of light… Light travels three hundred million meters in a second i.e. 300,000,000 m/s So (forgetting the units for now) Energy = mass x (300,000,000) 2 or E = m (90,000,000,000,000,000) = m (9 x ) = m (9 x ). That’s a BIG lot

Mass What is the mass of 1 liter of water? A liter of water is defined to have a mass of one kilogram! one kilogram! m = 1 m = 1 So, E = 1 (9 X ) = 9 X Joules = 9 X Joules

What could we do with all this energy?

Energy & Power A Joule is the effort required to push one kilogram over a meter at an acceleration of one meter/second2. A Joule expended continuously for one second is a Watt. A liter of water, converted to energy could power a 1 watt light bulb for… 9x1016 seconds, or 2.5x1013 hours or ~3 billion years! (2/3 the age of the Earth)

A 100 Watt bulb… would only stay lit for 2.5 x hours! There are about 10 9 families on Earth There are about 10 9 families on Earth So let’s light 10 9 bulbs of 100 Watt power for 250 hours…! for 250 hours…!You spend the same amount of energy as a 100 watt bulb ! [ One joule is equal to about four food calories]

The downside 200,000 people have been killed by just 2 atomic bombs. One Hydrogen Bomb could kill 50 times as many!

Most environment friendly application All our energy comes from the Sun! The Sun has E=mc 2 as its source of energy.

Nuclear Fusion When 4 hydrogen nuclei are fused together into 1 helium nucleus, energy is released in the form of Light photons and particles called neutrinos. When 4 hydrogen nuclei are fused together into 1 helium nucleus, energy is released in the form of Light photons and particles called neutrinos.

But where does the mass come from? Mass of 4 hydrogen nuclei is more than that of 1 helium nucleus So after fusion a little bit of mass is left over. This mass deficit appears as the energy of light and neutrinos.

A look inside the sun The fusion happens 700,000 km deep in the Sun’s core. It requires a temperatures of 15 million o C.

Solar E = mc 2 How much mass does it convert each second in order to shine? If the Lifetime of the Sun is years, how much mass would it need in that time? Use m = E/c 2 ! The Sun emits 4 x joules per second

How do you convert any mass to Energy on Earth? Scientists are trying to make a sun on the Earth through fusion reactors that use hydrogen. Hydrogen is the simplest & lightest element. Hydrogen is abundantly found in water! Hydrogen fusion has been tried and tested in Nature and on Earth (in H-Bombs).

The only scientist that was able to accomplish sustained nuclear fusion..

What are the barriers to attaining nuclear fusion? Hydrogen is a diffused gas and it is difficult to get its nuclei close enough to fuse. They start colliding into each other only at a temperature of 15 million degrees C. We need to keep it both hot & dense. A large amount of energy is needed to start the reaction and to prevent it from running out of control.

Do it yourself application for E=mc 2 Solar Cookers Solar Heater Solar Lighting