Sometimes things happen by chance. 
Sometimes things happen by chance. 

Think about rolling two dice. You cannot know the next roll. But some sums happen more often. A sum of seven happens a lot. It happens twice as often as four.
People have used chance for a long time. Ancient people used dice to learn about fate. Long ago, people in China studied odds. Later, math helped us understand chance better.
In science, randomness is a tool. It helps us make better computer programs. It also helps us study how life changes. We use random picks to learn about groups. We can even draw names from a hat.
Randomness helps us see how the world works.
Randomness is when things happen without a clear pattern. 
People have studied chance for a long time. 
Today, scientists use randomness as a tool. It helps us build better computer programs. It also helps us study how life changes. In biology, random changes in genes help life evolve. In science, we use random picks to learn about groups. We might draw names from a hat. This is called a random sample. It helps us get fair data. 
Randomness is when information lacks a definite pattern. 

Mathematicians use special tools to study these chance events. They use random variables to assign numbers to different outcomes. This makes it easier to calculate the chance of something happening. A random process is a sequence where outcomes do not follow a set pattern. These processes follow a rule called a probability distribution. In statistics, people use random selection to pick items from a group. Imagine a bowl with 10 red marbles and 90 blue marbles. A random pick gives you a one in ten chance for red. This method helps researchers get a fair look at a whole population.
People have wondered about chance for thousands of years. 
Many different sciences rely on the study of randomness today. In biology, random changes in genes help living things evolve. For instance, the exact spot of a freckle on skin seems random. In physics, some tiny particles act in ways that are truly random. It is impossible to predict exactly when a single unstable atom will decay. Even in math, some numbers have random parts. The digits of the number pi never repeat in a cycle.
Randomness is also a very helpful tool for modern technology. Computer scientists found that adding randomness can make algorithms work better. These randomized algorithms can sometimes beat the best standard methods. In communication, random disturbances are often called noise. This noise can be a problem in a signal. However, researchers also use random numbers to run big computer simulations. These are called Monte Carlo methods. They help scientists solve hard problems by using many random inputs. Even though randomness can seem messy, it helps us understand the world.
Randomness describes a lack of definite patterns or predictability in information. While individual random events are unpredictable, they often follow a known probability distribution. This means that over many repeated trials, the frequency of different outcomes becomes predictable. For example, when throwing two dice, you cannot predict a single roll. However, a sum of seven will tend to occur twice as often as a sum of four. In this scientific view, randomness is not just haphazardness. Instead, it is a formal measure of the uncertainty surrounding an outcome. 
Mathematics and statistics use specific constructs to manage this uncertainty. A random variable is a tool that assigns a numerical value to every possible outcome in an event space. This association allows researchers to calculate the probabilities of specific events. When these variables form a sequence without a deterministic pattern, it is called a random process. These processes evolve according to probability distributions. Scientists also use Monte Carlo methods, which rely on random inputs from generators to solve complex problems. These techniques are essential in the field of computational science. 
Randomness can also be applied to the selection of items from a population. In a simple random sample, the probability of choosing a specific item is equal to its proportion in that population. Consider a bowl containing 10 red marbles and 90 blue marbles. A random selection mechanism would give a red marble a probability of 1/10. If the population contains distinguishable items, a truly random process requires that every member has an equal probability of being chosen. This ensures that the selection is unbiased and representative of the whole group.
History shows that humans have long struggled to understand chance. 
In the physical sciences, randomness plays a fundamental role. In the 19th century, scientists used the random motions of molecules to develop statistical mechanics. This helped explain thermodynamics and the properties of gases. In quantum mechanics, many interpretations suggest that microscopic phenomena are objectively random. For instance, if you place a single unstable atom in a controlled environment, you cannot predict exactly when it will decay. You can only calculate the probability of decay within a certain timeframe. While some "hidden variable" theories suggest there are underlying causes, many scientists accept this irreducible randomness as a core part of nature.
Biology also relies on random processes to function. The modern evolutionary synthesis suggests that diversity in life comes from random genetic mutations followed by natural selection. While the location of a mutation might be somewhat protected, the mutations themselves are random. This randomness can even lead to the formation of entirely new behaviors and possibilities. In the animal kingdom, randomness serves as a survival strategy. For example, insects in flight often move with random changes in direction. This makes it difficult for predators to predict their trajectories and catch them.
Finally, randomness is a vital tool in modern information and computer science. In algorithmic information theory, a string of bits is considered random if it cannot be compressed. This is known as Kolmogorov randomness. In communication theory, randomness in a signal is referred to as "noise," which consists of transient disturbances. While noise can be a nuisance, computer scientists have learned to use randomness to their advantage. By deliberately introducing randomness into computations, they create randomized algorithms. In some specific cases, these randomized methods can actually outperform the best deterministic ones.
🖼️ Images & Media (5)
More to explore
✨ What else?
Related topics you might enjoy
🔬 Go deeper
More advanced topics to explore
🪜 Step back
Simpler topics to build understanding
What is Nepedia?
A free, ad-free encyclopedia for children. Every article is written at five reading levels, so the same page works for a five-year-old and a fifteen-year-old — use the level switcher above to see this one change. No account needed to read.