This is a trick question, because in the world as we know it, entropy never decreases, since the chance of this happening approaches and infinitely small fraction.
To answer the question though:
Take any closed system of events that you've observed, and rewind the events as if you were "going back in time".
Example: An egg the has splattered all of a sudden recombines off the floor and becomes a whole egg again.
Some scientists believe that the last time entropy ever decreased in our universe was right before the big bang. Since this chance occurrence, entropy throughout the whole universe has been steadily increasing.
My addition (person 2) - However, entropy CAN decrease locally, just not universally. Essentially entropy rests on the fact that work ultimately comes from a flow of heat energy from high to low, eventually balancing out. Once all the heat energy is uniform in the universe, we will experience "heat death" at which point no work will be able to be done. However, in systems WITHIN the closed system of the universe, entropy CAN be decreased. Freezing an ice cube, if you follow the entropy equation which I don't have with me, is one example of this. The cost of this local decrease in entropy is a universal increase in entropy from the heat released that is greater than the local decrease in entropy, thus the second law is not violated. Another example is biological growth. We humans develop from a single cell into a vastly complex arrangement of cells, but at the same time we produce heat that increases universal entropy more than our bodies decrease it.
Ice melting is a good example - energy is used to melt the ice but no work is done so it is sometimes called useless energy - check Wika Dictionary def.
Take a bag of red marbles and a bag of blue marble and dump them together on a table top. You will notice that the marble mix together instead of segregating into coloured groups. This in entropy.
There are macroscopic and microscopic examples of increasing entropy, all of which are also examples of increasing disorder and randomness.
Macroscopic:
Watch yourself get old.
Break something.
Watch your tea get cold.
In the study of thermodynamics and quantitative science, the examples usually involve the rearrangements of atoms and molecules inside matter and the change in entropy is given by dS=dQ/T.
A good example is the melting of an ice cube. dQ is the energy (heat) it takes to melt the ice cube. (dQ=3334 Jules per gram or about 80 calories per gram). T is the absolute temperature of melting ice, usually 273 K.
Now, this is not the whole story since the volume of the water and ice are different in normal daily life, and there are complexities of thermodynamics that are being skipped. Even so, ice melts, randomness of water molecules increases and entropy of the water increases.
Another microscopic example can be given when you create magnetism in a metal like iron and the internal organization is made more organized and entropy of the iron decreases. (Or course, total entropy always increases, so entropy of the magnetization creating process must increase or it must give off heat.)
Entropy is a thermodynamic property dealing with disorder. For example, a gas would have a higher entropy than a solid, because the molecules are more disordered. Entropy, along with enthalpy, can be used to determine the spontaneity of a reaction.
The most blatant example of entropy occurring in a living system is death. No matter how much energy is put into keeping a living system in order, it eventually falls into decline. In this sense, the lack of predictability of living systems, is actually quite predictable.
A pile of papers being scattered and Gas molecules expanding to fill their container
Relationships break down... material things break get old, useless... people get old, get sick and die...
It's not much use to give "examples of entropy"; it is an abstract concept that you must try to understand as such.
Anyway, any matter that has heat energy, has entropy.
The entropy of the universe is increasing
It's not that entropy can't be reversed, it's that the entropy of the universe is always increasing. That means that while you can reduce the entropy of something, the entropy of another thing must go up even more so that in total, the entropy goes up.
yes because it is a naturally occurring process and all naturally occurring processes result in an increase in entropy.
Being alive increases the entropy of the world because we consume food and give off heat. Since I like being alive, I'm all in favor of increasing world entropy!
that obama is the worst prez ever.
Only by increasing the entropy of another system.
The entropy of the universe is increasing
To feed the rise in Entropy. Enthalpy is a constant, but Entropy is always increasing.
It's not that entropy can't be reversed, it's that the entropy of the universe is always increasing. That means that while you can reduce the entropy of something, the entropy of another thing must go up even more so that in total, the entropy goes up.
may be for increasing it's entropy
yes because it is a naturally occurring process and all naturally occurring processes result in an increase in entropy.
Being alive increases the entropy of the world because we consume food and give off heat. Since I like being alive, I'm all in favor of increasing world entropy!
Ice has an ordered structure.
that obama is the worst prez ever.
It is expanding, It is getting cooler, It's entropy is increasing.
ice, liquid water, and steam
endothermic, increasing entropy