The Difference Between Living and Non-Living Nature: How to Grow Crystals at Home
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What is the difference between living and non-living things?
The difference between living and non-living things comes down to a set of life processes: living things grow from within, feed, breathe, excrete waste, respond to their surroundings, reproduce, and are built from cells, while non-living things do none of these. Life is not always obvious at a glance, because growth happens in motionless organisms too. Grass and mushrooms, shrubs and trees, sea corals, and sponges all grow and live without moving from place to place.
A stone — a cobble or any other rock — clearly does not grow in this way. For this reason rocks are often called part of "dead nature." Yet the boundary between life and non-life can seem blurry, because some non-living objects, such as crystals, do appear to grow. The sections below define each category, list the criteria that separate them, and walk through hands-on experiments you can do at home.
Definition and basic characteristics of living things
Living things are organisms that carry out the seven core life processes — nutrition, respiration, excretion, movement, growth, sensitivity, and reproduction — and are made of one or more cells. Humans, animals, plants, earthworms, and microorganisms are all living things because they perform every one of these functions. A definition of life rests on this whole package working together, not on any single trait in isolation.
What are the characteristics of living organisms?
The properties of living organisms can be summarized as a checklist that every living thing satisfies. If an object shows all of these, it is alive:
- Nutrition — taking in or making food for energy and growth.
- Respiration — releasing energy from food, usually using oxygen.
- Excretion — removing the waste products of metabolism.
- Movement — moving the whole body or parts of it.
- Growth and development — increasing in size and complexity from within.
- Sensitivity — responding to stimuli such as light, heat, and touch.
- Reproduction — producing new individuals of the same kind.
A useful memory aid taught in science classrooms is the word "MRS GREN" (Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, Nutrition), which captures these characteristics of living things in a single acronym.
Growth and development in organisms
Growth in living things happens from the inside out as cells divide and the body builds new tissue from absorbed materials. A seed becomes a seedling and then a flowering plant; a child grows into an adult through many coordinated stages. This internal, organized growth is paired with development — a change in form and function over a life cycle that has a defined lifespan, from birth or germination through maturity to death.
Nutrition and digestion
Nutrition is how living things obtain the matter and energy they need to live, and it differs sharply between plants and animals. Plants are autotrophs: they make their own food through photosynthesis, using sunlight, water, and carbon dioxide to produce glucose. Animals and humans are consumers that take in food and break it down through digestion, absorbing the nutrients to build and repair tissues of their own bodies.
Respiration and gas exchange
Respiration is the chemical process by which cells release energy from glucose, and it is part of every organism's metabolism — the sum of all chemical reactions that keep it alive. Animal respiration typically draws in oxygen and releases carbon dioxide. Plants respire too, around the clock, exchanging gases through pores in their leaves; during daylight they also carry out photosynthesis, which takes in carbon dioxide and gives off oxygen. The energy released by respiration powers movement, growth, and every other life process.
Excretion and waste removal
Excretion is the removal of the toxic by-products of metabolism, and every living thing does it. Humans excrete carbon dioxide through the lungs and urea through the kidneys; plants release excess oxygen and water vapour through their leaves. Without excretion, waste chemicals would build up and poison the organism — which is why this process is a defining sign of life rather than an optional one.
Movement and energy in organisms
Living things move, but movement does not always mean locomotion across a landscape. Animals show locomotion — walking, swimming, flying — while rooted plants move by bending toward light or opening and closing flowers. All of this movement is powered by the energy released during respiration. The key point is that the action originates within the organism, driven by its own stored chemical energy, not by an outside push.
Reproduction and inheritance
Reproduction is the ability of living things to produce new individuals and pass on their characteristics to the next generation. It can be sexual, combining genetic information from two parents, or asexual, producing offspring from a single organism. Through reproduction, traits are inherited, so that offspring resemble their parents — a feature no non-living object can imitate.
The cellular structure of living things
All living things are made of cells, the microscopic building blocks of life. A cell contains protoplasm, the living jelly-like material in which life's chemical reactions take place. Some organisms consist of a single cell; humans, animals, and plants are built from trillions of them organized into tissues and organs. This cellular, protoplasm-based composition is one of the clearest microscopic differences between a living organism and a lump of non-living matter.
Definition and basic characteristics of non-living things
Non-living things are objects that do not perform any of the life processes — they neither feed, breathe, excrete, grow from within, nor reproduce. Rocks, water, metal, glass, and crystals are examples of non-living things. They may change, move when pushed, or even increase in size, but these changes are driven entirely by external physical forces rather than by internal biology.
What are the characteristics of non-living objects?
The characteristics of non-living things are essentially the absence of the life processes plus dependence on outside forces for any change:
- No nutrition, respiration, or excretion.
- No internal growth — any increase in size comes from material added on the outside.
- No reproduction and no inheritance of traits.
- No genuine response to stimuli on their own.
- No cells or protoplasm.
- Movement only when an external force acts on them.
How crystals grow as an example of non-living nature
Crystals are a striking case because, before our very eyes, these representatives of non-living nature can grow — for instance, crystals of table salt, alum, or other substances.
Preparing a solution for growing crystals
Crystals are grown in saturated solutions, which are prepared as follows. Add table salt or alum — aluminium or chromium alum — or some other crystalline substance little by little to warm water, stirring with a spoon or glass rod, until no more will dissolve. Filter the resulting solution through cotton wool or filter paper and pour it into a glass or a deep dish.
Cover the top with gauze to keep out dust and set it somewhere undisturbed. After a few days, small transparent crystals appear on the bottom of the glass or dish. To grow large crystals, lower a woollen thread into the saturated solution. Wind the other end around a wooden stick laid across the rim of the glass or dish.
Growing large crystals
After a while, tiny crystals form on the woollen thread. Leave two or three crystals on the thread at first, and then, once they have grown, keep only one — the largest crystal of regular shape. Lower it back into the glass with the saturated solution, making sure it touches neither the bottom nor the walls of the glass, and let it grow.
The crystal will gradually become larger and larger. In this way you can easily grow a genuinely big crystal of aluminium alum or copper sulphate.
Growth by accretion in non-living things
Growth in non-living things happens by accretion — the addition of material on the outside — rather than from within. When a crystal enlarges, matter dissolved in the solution is deposited unchanged on its faces, following physical laws of crystal growth, the laws of deposition of substance on its surfaces. This is the opposite of how a plant or animal grows: a living organism absorbs the substances it needs from soil or food and then "builds" the tissues of its own body out of them.
Repairing damage: a crystal versus a living organism
Both crystals and living organisms can seem to "heal," but the underlying processes are completely different. A crystal restores its shape by depositing more material from solution, while a living organism rebuilds lost parts using its own cells. Comparing the two side by side shows why apparent similarities do not erase the line between life and non-life.
How a crystal "heals" damage
Besides growth, crystals reveal another curious property that at first glance seems to blur the difference between living and non-living matter. Take a crystal out of the solution and carefully break off its corners with pliers or scissors, then lower it back into the solution. To one's great surprise, after some time the mutilated crystal will have restored its former appearance — the crystal seems to have healed the damage done to it.
Repair of damage in living nature
Repair of damage in living nature happens in a completely different way. Everyone knows, or has seen for themselves: grab a lizard by the tail and it instantly breaks off, and the lizard slips away. By losing part of its tail it gains its freedom and its life.
If you take an injured lizard and care for it at home, you will soon notice that the tail gradually begins to grow back. It will only be shorter than before and somewhat changed in shape.
The crystal, by contrast, fully restores its damage and even becomes somewhat larger, yet there is no miracle and no sign of life: the crystal, as science has firmly established, obeys special growth laws, the laws of deposition of substance on its faces. That is why there is nothing in common between a damaged crystal and a maimed lizard's tail. Quite different causes are at work. On a crystal, the substance dissolved in the solution is laid down unchanged, whereas plants and animals take up the substances they need from soil or food and then "build" the tissues of their bodies from them (more on this: Roots supply the plant with water).
Criteria for distinguishing living from non-living
To classify something as living or non-living, check it against the life processes: anything that feeds, respires, excretes, grows from within, responds to stimuli, reproduces, and is made of cells is alive. A single shared feature — growth, movement, or even self-repair — is never enough on its own, because non-living things like crystals can imitate one of these without being alive. The reliable rule is that living things satisfy the whole set together.
Comparison table of living and non-living nature
| Feature | Living things | Non-living things |
|---|---|---|
| Nutrition | Make or take in food | None |
| Respiration | Release energy from food | None |
| Excretion | Remove metabolic waste | None |
| Growth | From within, by cell division | By accretion on the outside, if at all |
| Movement | Self-driven by stored energy | Only when pushed by external force |
| Reproduction | Produce offspring, pass on traits | None |
| Structure | Made of cells and protoplasm | No cells |
| Damage repair | Living cells rebuild tissue | Material redeposited from outside |
Examples of living and non-living things
Examples of living things include humans, animals, earthworms, a sunflower and other plants, mushrooms, corals, and sponges — even the ones that never move from place to place. Examples of non-living things include rocks, water, salt crystals, copper sulphate crystals, metal, and glass. A third category, once-living things, covers items such as wood, leather, paper, and fossils: they came from organisms that were once alive but no longer carry out life processes.
Common science misconceptions
A frequent misconception is that anything which moves is alive and anything still is not — but rooted plants are alive while a rolling stone is not. Another is that growth alone proves life, which the growing crystal disproves. Students also often assume that all living things must move around (locomotion), forgetting that plants are firmly anchored. Clearing up these ideas is a key goal of biological classification lessons, from early science vocabulary in Grade 1 right up to the 11th grade biology curriculum, where the molecular basis of metabolism and photosynthesis is studied in depth.
Experiments and practical tasks for independent study
The best way to understand living versus non-living things is through hands-on investigation, and the crystal-growing project above is an ideal starting point. Try these DIY activities to compare growth, response, and repair directly:
- Grow a salt or copper-sulphate crystal and measure how its size changes day by day — then compare it with a germinating bean seed.
- Plant a sunflower seed and record its growth and its turning toward light to observe sensitivity in action.
- Place an earthworm on damp soil and watch how it responds to light and touch.
- Break a corner off a grown crystal, return it to solution, and observe accretion "repair" versus biological regrowth.
- Compare a watered houseplant with a dry stone over a week to see which one changes by itself.
Teachers can extend these into full lesson plans aligned to the Next Generation Science Standards (NGSS), which is developed with organizations such as WestEd. Video-based resources like Generation Genius, BYJU'S Biology, and KnowAtom offer quiz games, assessments, and interactive activities on this topic; many use a freemium model with free trial lessons and a paid subscription for full access. If a streaming lesson is blocked behind a video paywall or a network error, that is a separate access issue rather than a science question — see the note below.
Discussion and review questions
Use these questions to check understanding and to spark classroom or family discussion:
- Name three life processes a crystal cannot perform.
- Why is a growing crystal still classed as non-living?
- How does a plant's nutrition differ from an animal's?
- Why isn't movement alone proof that something is alive?
- What is the difference between how a lizard regrows its tail and how a crystal restores its corners?
A quick note for anyone watching the lesson videos online: streaming platforms hosted through services such as Wistia and protected by Cloudflare network security can sometimes return Error Code 1020 ("Access Denied"). This error is triggered by a security rule on the web server, not by a problem with your device, and it has nothing to do with the biology content. To resolve or prevent error 1020, refresh the page, disable any VPN or proxy, clear your browser cache and cookies, switch networks if a connection timeout occurs, and contact the site's support if the block persists. Discussions on communities like Reddit confirm that these video security and connectivity problems are usually fixed on the provider's side.
