The Science Library

Finding and linking to the amazing things in this Universe

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14-billion-years-later noted: How Do Batteries Work? I had a request from an anon, so here goes. The first thing we need to know about batteries is that in essence what they’re doing is converting stored chemical energy into electrical energy. They do this by a series of reduction-oxidation reactions (redox). The first step involves the positively charged anode (anodes attract negatively charged ions called anions), at the anode electrons are moved from the electrolyte into the anode where they generate a voltage (which is a potential difference between energies at 2 points) and electromotive force. This is the oxidation step of the reaction. The electrolyte then converts into another compound or simply changes oxidation state. The electrons meanwhile go about their business and do whatever work they have to do before flowing into the cathode of the battery. At the cathode the corresponding reduction reaction occurs, quite separately to the oxidation component. Here electrons flow from the cathode into the second electrolyte which undergoes another chemical change. To complete the circuit some exchange of ions has to occur to make sure the flow continues, this is usually mediated by a salt bridge which connects the two electrolytes. Hope that helps!Image

14-billion-years-later noted:

How Do Batteries Work?

I had a request from an anon, so here goes. The first thing we need to know about batteries is that in essence what they’re doing is converting stored chemical energy into electrical energy. They do this by a series of reduction-oxidation reactions (redox). The first step involves the positively charged anode (anodes attract negatively charged ions called anions), at the anode electrons are moved from the electrolyte into the anode where they generate a voltage (which is a potential difference between energies at 2 points) and electromotive force. This is the oxidation step of the reaction. The electrolyte then converts into another compound or simply changes oxidation state. The electrons meanwhile go about their business and do whatever work they have to do before flowing into the cathode of the battery. At the cathode the corresponding reduction reaction occurs, quite separately to the oxidation component. Here electrons flow from the cathode into the second electrolyte which undergoes another chemical change. To complete the circuit some exchange of ions has to occur to make sure the flow continues, this is usually mediated by a salt bridge which connects the two electrolytes. Hope that helps!

Image

(via likeaphysicist)

Filed under physics chemistry

9 notes

I’ve never seen M27 like this before. From Astronomy Picture Of The Day; December 27, 2011: M27: The Dumbbell Nebula Bill Snyder (Bill Snyder Photography) The first hint of what will become of our Sun was discovered inadvertently in 1764. At that time, Charles Messier was compiling a list of diffuse objects not to be confused with comets. The 27th object on Messier’s list, now known as M27 or the Dumbbell Nebula, is a planetary nebula, the type of nebula our Sun will produce when nuclear fusion stops in its core. M27 is one of the brightest planetary nebulae on the sky, and can be seen toward the constellation of the Fox (Vulpecula) with binoculars. It takes light about 1000 years to reach us from M27, shown above in colors emitted by hydrogen and oxygen. Understanding the physics and significance of M27 was well beyond 18th century science. Even today, many things remain mysterious about bipolar planetary nebula like M27, including the physical mechanism that expels a low-mass star’s gaseous outer-envelope, leaving an X-ray hot white dwarf.

I’ve never seen M27 like this before.

From Astronomy Picture Of The Day; December 27, 2011:

M27: The Dumbbell Nebula 
Bill Snyder (Bill Snyder Photography)

The first hint of what will become of our Sun was discovered inadvertently in 1764. At that time, Charles Messier was compiling a list of diffuse objects not to be confused with comets. The 27th object on Messier’s list, now known as M27 or the Dumbbell Nebula, is a planetary nebula, the type of nebula our Sun will produce when nuclear fusion stops in its core. M27 is one of the brightest planetary nebulae on the sky, and can be seen toward the constellation of the Fox (Vulpecula) with binoculars. It takes light about 1000 years to reach us from M27, shown above in colors emitted by hydrogen and oxygen. Understanding the physics and significance of M27 was well beyond 18th century science. Even today, many things remain mysterious about bipolar planetary nebula like M27, including the physical mechanism that expels a low-mass star’s gaseous outer-envelope, leaving an X-ray hot white dwarf.

(via wigmund)

Filed under astronomy