7 Tips for Teaching Children Science

Getting kids interested in science at an early age is very important. It's easier than

you think. Science does not have to be something mysterious. It is happening all

around us, and you can use everyday things to encourage your children's interest

and knowledge.

Most parents believe that they can't help their children with science. But you don't

need a advanced scientific degree to teach young children science. All you need is a

willingness to try, to observe the world, and to take the time to encourage their

natural curiosity.

You can help by having a positive attitude toward science yourself. Then start simply

by asking your child questions about the things you see every day. Why do you think

that happened? How do you think that works? And then listen to their answer

without judging it or judging them. Listening without judging will improve their

confidence, and help you determine just what your child does or does not know.

You can turn every day activities into science projects. For example,

don't just comment on how bright the moon is one night. Ask questions about why

it's brighter tonight, why does it change shape, etc. You can observe the moon's

phases throughout a month, and turn that activity into a science project, without

even mentioning the words "science project". For a child that likes cooking, observe

how milk curdles when you add vinegar, or how sugar melts into syrup. Try baking

a cake and asking why does the cake rise? What happens if you forget to put in

some ingredient? Voila! Instant science project idea, without being intimidating to

you or your child.

Different kids have different interests so they need different kinds of science

projects. A rock collection may interest your young daughter but your older son may

need something more involved. Fortunately, it's not hard to find plenty of fun

projects. Knowing your child is the best way to find enjoyable learning activities.

Here are some more tips:

- Choose activities that are the right level of difficulty - not too easy nor too hard. If

you are not sure, pick something easier since you don't want to discourage a child

by making science frustrating. You can always do the harder project later on.

- Read the suggested ages on any projects, books or toys labels, but then make

sure that the activity is appropriate for your child, regardless of age. Your child's

interest and abilities are unique. If a child interested in a topic,they may be able to

do activities normally done by older kids, while a child who is not interested may

need something easier aimed at a younger ages.

- Consider how well the type of project matches your child's personality and

learning style. Is the project meant to be done alone or in a group? Will it require

adult help or supervision?

- Choose activities matched to your environment. A city full of bright lights at night

may not be the best place to study the stars. But during your vacation to a remote

area, you may be able to spark an interest in astronomy.

- Let your child help choose the project or activity. It's easy enough to ask. Rather

than overwhelm them, suggest 2 or 3 possibilities. When a child picks something

they are interested in, they will enjoy it and learn more from it.

Go ahead. Try it and see for yourself how easy it is the spark the interest of a child.

 Read more of his articles about science fairs and science projects at Science Made Simple (http://www.sciencemadesimple.com).

30 Points, How Science Has Changed Our Lives

If we look life 100 years ago, and compare that with the today's life, we will notice that Science has dramatically changed human life. With the dawn of the Industrial Revolution in the 18th century, the effect of Science on human life rapidly changed. Today, science has a profound effect on the way we live, largely through technology, the use of scientific knowledge for practical purposes.

Some forms of scientific inventions have changed our lives entirely. For example the refrigerator has played a major role in maintaining public health ever since its invention. The first automobile, dating from the 1880s, made use of many advances in physics, mathematics and engineering; the first electronic computers emerged in the 1940s from simultaneous advances in electronics, physics and mathematics. Today we have extra high- speed super computers with 100 % accuracy.

Science has enormous influence on our lives. It provides the basis of much of modern technology - the tools, materials, techniques, and sources of power that make our lives and work easier. The discoveries of scientists also help to shape our views about ourselves and our place in the universe.

Research in food technology has created new ways of preserving and flavoring what we eat. Research in industrial chemistry has created a vast range of plastics and other synthetic materials, which have thousands of uses in the home and in industry. Synthetic materials are easily formed into complex shapes and can be used to make machines, electrical, and automotive parts, scientific, technical and industrial instruments, decorative objects, containers, packing materials and many other items.

1: The use of science in daily life has helped us a good deal in solving problems, dealing with the maintenance of health, production and preservation of food, construction of houses and providing communication and trans-portational (related to transport) facilities. With the help of Science we have controlled epidemics and much other kind of diseases. Now we know the basic structure of DNA and Genetic Engineering is conducting research to find out the right and correct Gene Therapy to overcome all the diseases.

2: Science has changed the people and their living, life style, food habits, sleeping arrangements, earning methods, the way of communication between people and recreational activities. All kinds of music systems, computer games, electronic video games, DVDs, cinema entertainment and communication have been brought to our door with the help of Science. The life of man was very different from what it used to be 100 years back. Science has given ears to the deaf, eyes to the blind and limbs to the crippled. Science has adequately, energetically and productively advanced, changed, civilized, enhanced and progressed human life. Science has brought sophistication to human life.

In short science has changed, improved, enhanced, modified and refined human life in all ways.

3: Today with the help of Science we can explain what was strange and mysterious for the people of the past. The Science of Genetics opening new doors of understanding the human gene and cell.

4: Now human beings have become more critical and less fearful than our fore-fathers and ancestors.

5: Two hundred years ago death rate among children was very high. In those days seven out of eight babies died before their first birthday. Now with the help of vaccines, medications and proper health care system life expectancy has improved. Now people live longer and safe lives as compared to 200 years ago. Biochemical research is responsible for the antibiotics and vaccinations that protect us from infectious diseases, and for a wide range of other drugs used to defeat specific health problems. As a result, the majority of people on the planet now live longer and healthier lives than ever before.

6: After that and up to the age of 12 one used to fall in a prey to diseases like small pox, measles, whooping- cough, scarlet fever and diphtheria. Now Science has defeated these diseases.

7: At a later stage again one was under constant threat of yellow fever, malaria, typhus, cholera, typhoid and influenza. Today we have vaccines and medical aid to cope with these health problems. Further research is underway to find out the causes and treatment of these and other diseases.

8: From one person the disease used to spread among the other people. It is called Epidemics. Now with the help of Vaccines and Medications we have defeated these diseases. But still Science has to do more research and has to fight with other arenas of diseases.

9: Life was uncertain. It was rare to see to somebody thirty years old because due to diseases many people died earlier than the age of thirty. These conditions were prevailing just a short while ago.

10: In everyday life, we have to communicate with different friends and relatives, various official people and for general purposes. And many people to be contacted can be at very far off distances. However, time and distance both have been conquered by Science. Whether we want to communicate or travel, both are possible quickly, briskly and expeditiously.

11: These days there are very little chances of babies catching diseases, because births normally take place in hospitals under the supervision of a team of specialist doctors. Science has invented vaccines for young babies to protect them against future life illnesses.

12: Young people are also given medical treatment in time and these days the man lives for about seventy years.

13: Science and scientific methods have helped in finding out the cause of disease and its prevention.

14: Sanitary condition in the past was deplorable. Now we have better sanitary systems.

15: The city streets were unpaved; there was no proper drainage system. Garbage and other refuse was seen everywhere. Pigs were seen wandering through the streets. People got water from filthy wells. Now filtered mineral water is available to overcome diseases. Solid waste management is not a problem now a days, it is the duty of the city municipal committees to manage and dump it with the latest machinery and equipments

16: Now all these defects have gone. There is cleanliness everywhere. It is illegal to throw garbage into the streets. There is a proper drainage system and new and improved methods for solid waste management as it has been told earlier. There are separate departments that bother about sanitary condition of the towns.

17: A century ago for house hold purposes water was carried from wells outside in buckets. It sometimes proved injurious to human health. Moreover, it was insufficient for the daily needs. But now water filters have become a thing of common usage.

18: Now there is sufficient supply of water in cities. For example Los Angeles gets water through pipes from Colorado River, which is 340 miles away. This water is supplied to Los Angeles after the proper water filtration process.

19: With the help of science there is change in our food also. We get varieties of food. In the past, food could not be preserved. But now the quick freezing methods have made possible preservation possible. Due to modern technologies like dehydration and sterilization there is no chance of food poisoning. We get all kinds of fruits, meats and vegetables. Even those fruits and vegetables which are out of season.

20: Not only our eating habits are changed, but also there are improvements in our houses. Means of transport has also undergone a big improvement and change.

21: Science has also changed our attitudes. Superstitions have been discarded, because there is no scientific basis for them. Now people do not fear cloud thunders.

22: Now people no more believe that diseases are caused by evil spirits.

23: Astrology and fortune- telling have lost popularity as compared to 100 years ago. Nobody now fears black cats, broken mirrors and the number 13. Because science has proved that these kinds of fears are un-scientific and illogical.

24: Science has changed the longstanding false notions of the people, which are not supported by Scientific Facts.

25: Research in the field of science and technology has made people open-minded and cosmopolitan, because the Scientist does not like to travel on the beaten track and he always tries to find out new things, new explorations, new discoveries and new inventions.

26: Science has also brought medical equipments that help to save human life. The kidney dialysis machine facilitates many people to survive kidney diseases that would once have proved fatal, and artificial valves allow sufferers of coronary heart disease to return to active living. Since the 1980s, lasers have been used in the treatment of painful kidney stones. Lasers are used when kidney stones fail to pass through the body after several days, it provides a quick and low-pain way to break up the stone and allow the stones to be easily passed through the body. This technique is called Lithotripsy.

27: Arthroscopic surgery is a technique using fiber optics to probe complex joints such as knee, shoulder, ankle and wrist to evaluate injury. It is a minimally invasive operation to repair a damaged joint; the surgeon examines the joint with an "arthroscopy" while making repairs through a small incision.

28: 200 years ago nobody even knows that human body parts can be replaced or transplanted. Now kidney transplant is widely used to save human lives around the globe. Dr. Christian Bernard first of all invented the method of heart transplant. Eye transplant techniques are used in these days to see again this beautiful world, for those who have lost their eyes. These all are the blessings of Science.

29: Ultra-high-frequency (UHF) waves are allocated for variety of uses, including television, cellular phones, public safety radios, business radios, military aircraft communications, military radar, cordless phones, baby monitors, etc. So, whether someone is watching over-the-air TV, talking on cell phone, having police/fire/ambulance dispatched to an emergency they are experiencing, or having national airspace protected by military aircraft, they all are benefitting from the science that has allowed the use of UHF waves. Even it is used to treat some illnesses.

30: For communication, now we have fixed wire telephones, moveable wireless phone sets, cordless phones, mobile phones, wireless, video conferencing, Internet, Broad Band Internet, E-mail, Social Networks, Satellite Communication and many other ways to communicate. These all are blessings of Science. Today we are better aware of what is happening around the globe due to satellite television channels. The benign and benefits of science for human life are endless.

Mushroom Books - Learn How to Pick Wild Mushrooms Using a Book

One of the great things about mushrooms and fungi is that they will pretty much grow anywhere in the wild, especially here in the UK, and the chances are that there are some interesting, exciting and most importantly edible mushrooms that are growing not very far from you. There are thousands of species of mushrooms that grow in the UK alone, and without either some kind of encylopedic knowledge or (and perhaps more plausible), a decent mushroom guide book.

Armed with just a mushroom book and penknife, anyone can go searching for mushrooms if they like. You have to be careful of the places that you search for mushrooms however, for example you will need to stay away from private property (unless you have permission to pick fungi on their land), and you will need to heed any signposts and take care not to cause any kind of damage to the environment in which your mushroom hunting leads you. You mustn't pick too many mushrooms either, and currently there is a limit of 1.5kg per person in the UK, which is more then enough.

There are hundreds of mushroom guide books that are available for the would-be hunter to purchase, but it can be quite a hunt to actually try to find a decent book. Its best that you buy a couple of good quality books, probably about 3 would be suffice for your average mushroom picker, and you must be willing to take time when trying to identify any wild mushrooms before consuming them.

Out of the many thousands of different kinds of mushrooms throughout the world, only a small fraction are actually edible, and unfortunately some of the fungi that you could encounter near you include poisinous ones, which have claimed the lives of many people. Therefore it is imperitive that you are sensible, and consult a decent guide book when deciding which mushrooms are edible, and which are best to leave behind.

In my opinion it would be best to purchase a decent identification book, like a kind of mushroom encyclopedia, which you could leave at home and refer to after collecting mushrooms to check that you are 100% certain that it is in fact the type of fungi that you believe it is. This book wouldn't be taken with you when out foraging for mushrooms in the wild, simply because they are always big and bulky. Instead, you should take one or two good edible species guide books. Most decent books which specialise in the edible, common species of fungi usually have pages dedicated to the inedible species also - this is extremely important because you need to know what not to pick, and what to stay well clear of! You will have to compare the inedible species section against any of your own pickings so you can be completely sure that what you are about to eat is completely edible.

In summary, anyone can go mushroom foraging but you will need to have a lot of common sense, patience, and you must also take some decent mushroom identification guides with you. I recommend that if you are interested in going mushroom hunting you should purchase at least 2 guide books, and make sure you are very sure when it comes to picking and eating mushrooms. They can, and will, kill you if you make an incorrect identification, and if you aren't sure of anything that you have collected then simply do not eat it, because it is not worth taking any chances whatsoever.

Digital Photography - Photographing Wild Mushrooms Toadstools and Fungi With a DSLR Digital Camera

Buying a nice DSLR digital camera is one thing, but finding really cool subjects to photograph can be slightly more challenging than we might have hoped. Pretty much everything that has its picture taken by your DSLR camera comes out looking awesome, so capturing a worthwhile subject makes it even better. So, what about getting down and dirty with some earthly nature and photographing wild mushrooms and toadstools, you will be surprised to know these make stunning pictures when done right.

Wild mushrooms, toadstools and fungi make an exceptional subject for photographers and are very popular and rewarding as the search can take you to a variety of different locations and settings which are ideal not only for these, but many other great and interesting subjects as well.

Not only are mushrooms extremely versatile but there are over 38,000 different varieties worldwide with over 70 percent being inedible, in fact it is highly recommended that the only mushrooms that anyone should eat are those that are bought from the grocery store as these are grown in monitored conditions.

Personally I find mushrooms and toadstools extremely photogenic and enjoy the rewards and many different images that can be produced by taking my time to photograph them.

When photographing anything specific it is always a good idea to put some thought into what can be used to make the picture turn out better as well as equipment to make it more comfortable for you to do so.

The majority of mushrooms tend to reside in forested areas, woodlands and along the edge of where these meet grassland or fields. One of the best times of year to find them in great abundance tends to be around autumn.

Equipment that might come in useful for great clarity is a small bean bag to stand the camera on for stability or a mini tripod, but as you really want a low to the ground shot or at least side on view with most mushrooms bean bags tend to lend themselves better to these situations.

Again for great clarity, use a remote control (electronic shutter release) so there is no camera movement when taking the shot. It has been proved that by reducing camera motion to zero when taking a picture the image can be as much as twenty percent better so certainly worth a little effort.

Also when photographing wild mushrooms and toadstools try where possible to use reflectors (even sheets of white or grey paper work to an extent) to harness and direct the natural light onto your subject as a flash unless external can sometimes saturate the images better qualities, mirrors work equally as well, but try not to cast direct sunlight onto the subject and be careful how mirrors are transported. (Ideally use the white sheets attached to a cardboard back with cocktail sticks pinned between it and the ground to support it).

Plastic sheeting or a mat is often a good idea as this will protect your clothing when kneeling or laying on wet or damp ground while you are setting up the camera. Ideally you want close ups rather than distance shots.

By using these methods for photographing wild mushrooms, toadstools and fungi you will certainly produce some exceptionally rewarding and inspiring images. You could also adopt and adapt this information for your general photography activities providing you with a more enjoyable and rewarding experience from all your efforts. Wishing you much success.

Knowing how to set up good pictures is one thing, but having the right equipment at a great price is also important. By visiting this informative DSLR Camera Guide site with a unique free offer you can discover why and which DSLR Camera would suit you. You can now see some of the best deals by going to: http://www.squidoo.com/dslr-camera-secrets-exposed

How To Photograph Fungi

Most photographers shy away from shooting fungi, mostly because it is not seen to be a glamourous thing to do. Yet these life forms are just begging to be photographed and the picture potential is there to be taken. Fungi can be found anywhere where organic matter is decaying, especially in woodland, and in particular around autumn and early winter.

To photograph fungi all you need is a simple set-up, so this form of photography is widely accessible and thoroughly enjoyable.

• Where To Find Fungi To Photograph

Different types of fungi have their own habitats, but most will be found growing in deciduous woodland. The best places to look for them are on fallen branches and decaying stumps. You can also find them among mossy areas and dense leaf litter. Another good place to find them is on tree trunks, when a telephoto lens will be required.

One thing to remember about fungi is that they spread as mycelia (very thin root-like structures) underground and absorb nutrients from decaying vegetation before revealing their existence on the surface as reproductive fruiting bodies we commonly see as toadstools or mushrooms. Mycelia can travel for a at least a mile underground.

• Your Photography Gear

Most lenses can be used to shoot fungi, but because some species can be rather small, a dedicated macro lens will be the preferred lens to use. Macro lenses give results that are lifesize. They also give you maximum aperture, which means you will get a brighter image that is essential in dark woodland.

If you do not have a macro lens you can easily use much cheaper, but effective, close-up filters. These do not affect your camera's automatic functions. Another possibility is the use of extension tubes.

An effective way of photographing fungi is to use a telephoto or a zoom lens from a distance to isolate the fungi from their surroundings. Actually, different focal lengths will help create different perspectives and results, so it is best to experiment.

A tripod, especially one that the legs can be splayed almost flat will be very useful when shooting fungi. If shooting at ground level, a beanbag will be very handy. Be sure to lay out a plastic groundsheet to kneel on in order to keep your legs dry.

In order to minimize camera shake, even though you are using a steadying tripod, it is best to take the shot with a remote release rather than pressing the shutter. Alternatively, use your camera's self-timer.

• Beware of Toxins

Although some mushrooms are edible, it is generally a good idea not to handle fungi unless you know the subject well. There are some types of fungi out there that are known to be poisonous and potentially deadly. So if you find that you need to clean bits of vegetation and dirt off a fruiting body, it will be safer to use a blower brush instead of picking off the particles with your fingers.

As soon as you have found a good looking fungus to photograph, be it the fruiting body of a puffball mushroom, a stinkhorn mushroom, a death cap mushroom or whatever, you need to figure out the best way to photograph it.

The good thing about photographing fungi is that they are static objects, so you have lots of time to shoot them. You have to take note of the surrounding light and the size and shape of the fruiting body.

If the amount of light is an issue, that will mean mounting your camera on a sturdy mount such as a tripod or a beanbag. Then, the actual exposure time will not matter too much. However, fungi being what they are, tend to grow in uneven and awkward places, so setting up your tripod can become a bit fiddly. Patience in setting up will always be rewarded.

• Lighting

Woodlands being dark places by nature mean that fungi generally prefer to grow in dark locations. Fungi are not plants, so they have no need for light in order to flourish. The dark environment in which you find the fruiting bodies means that the available light has to be supplemented.

A typical fruiting body like a mushroom has more light on the cap than on the underparts, so if you do not balance the light, a lot of detail will be missing in your photographs. You can rectify this by using a reflector or fill flash.

A reflector can be hand-held or placed nearby the fungus so that lateral light falls on the subject at an angle. By moving the reflector closer or farther away, you can vary the light intensity. You do not have to use a fancy foil umbrella like you might use in studio photography. Instead, you can use a white card or a piece of aluminium foil to act as the reflector.

Fill-flash is used to lighten the shadows. Normally it is best to reduce the output of the flash by a couple of stops to balance the flash with the ambient surrounding light. You will have to experiment on the subject distance.

Off-camera flash is generally the preferred method to use because of its versatility and the way it gives fungi a more natural look. You simply place the flash to the side or at an angle to create interesting backlighting, which will always be particularly impressive on translucent fruiting bodies.

• Image Sharpness

If your camera has mirror lock-up, use it. This will maximize image sharpness in the poor lighting conditions associated with fungi photography. Mirror lock-up works by locking-up the reflex mirror in a DSLR camera before firing the shutter. This reduces unwanted vibrations. It will work best when the camera is fitted to a tripod and when the self-timer or a remote release is also used.

Reproduction Fungi

Fungi are the member of eukaryotic organisms. They can be found everywhere and are omnipresent. In a recent study, fungi were declared to be closely related to animals rather than plants and for this reason they have been put in a separate group, i.e. different from plants, animals and microbes. Mycology is the branch of biology which deals the study of fungi.

Fungi do not have photosynthetic pigment, also known as chlorophyll, and therefore, they cannot prepare food and depend on others for it. They are a great help in decaying dead organism and clean the surroundings. Thus, making the place suitable for living.

Many modes of reproduction of fungi are responsible for their large numbers. Reproduction through spores involves scattering of spores from one place to another through winds, water etc. These spores give birth to new fungi.

Scientifically, more than 100,000 kinds of fungi have been found. Mushroom is one of the examples of fungi which is consumable. Mold, yeast, rust are other examples. Fungi reproduce by both sexually and asexually.

Asexual reproduction in fungi is more common than sexual reproduction. Almost every variety of fungi can reproduce by asexual means. Spore formation, fragmentation, budding and fission are the types of asexual reproduction. Vegetative spores or conodia are widely known.

Sexual reproduction in fungi is not very easy. This is achieved when the male gamete fuses with the female gamete. In the initial phase of reproduction, haploid hyphae come together. The fusion of male and female cells leads to the formation of fertile diploid cells, which are known as spores. These spores come out, get scattered and grow into new fungi.

Microbiology - A Brief Introduction to Microorganisms

Microbiology is the study of "small life" - in other words the study of all living organisms that are too small to be visible with the naked eye and are usually visible only through a microscope. Such organisms are referred to as microorganisms or microbes. Microorganisms were first observed over three hundred years ago and it is estimated that only one percent of the species of microorganisms that exist have been studied so far. Microbiology is a broad term that includes bacteriology, virology, mycology, phycology, parasitology, and other branches of biology.

Microorganisms include bacteria, archaea, viruses, protozoa, protists, microscopic fungi and moulds, yeasts, and microscopic algae. Note that viruses, though not always strictly classed as living organisms, are included.

Although it may not be quite obvious, the world of microbiology is quite enormous! In most cases, microorganisms are invisible in front of the naked eye. Microorganisms, or microbes, are usually observed through a microscope. Interestingly, the amount of microbes outnumbers humans exponentially. Though not entirely visible, microbes are all over the place. In fact, there are many bacteria that live peacefully inside your mouth. Yes, quite charming. In most cases, people who lack the understanding of microbiology would consider bacteria harmful. This is true, yet not entirely. Although many forms of bacteria are harmful, or pathogenic, there are still many helpful bacteria. Some bacteria can be harmful, while others are beneficial.

There are many types of bacteria, as well as other microbes, that are harmful to living organisms. Certain types of bacteria can cause damage to our bodily functions, or make us sick. Others can be annoying and cause us to have bad breath. One common example of a harmful bacterium is Escherichia coli, or E. coli. Although not all forms of E. coli are harmful, some virulent strains can cause gastroenteritis and even urinary tract infections.

Not all bacterial microorganisms are harmful. In fact, there are many bacteria that are essential for livelihood and well-being. One example is the photosynthetic bacteria. Obviously, these bacteria play a major role in photosynthesis. Photosynthetic bacteria contribute to a large portion of the world's photosynthesis production. Photosynthesis is important for us because the by product is oxygen!

Microbiology is an important field because it enables us to learn more about microorganisms. Microorganisms are numerous, and they come in many shapes and sizes.

Although it may not be quite obvious, the world of microbiology is quite enormous! In most cases, microorganisms are invisible in front of the naked eye. Microorganisms, or microbes, are usually observed through a microscope. Interestingly, the amount of microbes outnumbers humans exponentially. Though not entirely visible, microbes are all over the place. In fact, there are many bacteria that live peacefully inside your mouth. Yes, quite charming. In most cases, people who lack the understanding of microbiology would consider bacteria harmful. This is true, yet not entirely. Although many forms of bacteria are harmful, or pathogenic, there are still many helpful bacteria. Some bacteria can be harmful, while others are beneficial.

There are many types of bacteria, as well as other microbes, that are harmful to living organisms. Certain types of bacteria can cause damage to our bodily functions, or make us sick. Others can be annoying and cause us to have bad breath. One common example of a harmful bacterium is Escherichia coli, or E. coli. Although not all forms of E. coli are harmful, some virulent strains can cause gastroenteritis and even urinary tract infections.

Not all bacterial microorganisms are harmful. In fact, there are many bacteria that are essential for livelihood and well-being. One example is the photosynthetic bacteria. Obviously, these bacteria play a major role in photosynthesis. Photosynthetic bacteria contribute to a large portion of the world's photosynthesis production. Photosynthesis is important for us because the by product is oxygen!

Microbiology is an important field because it enables us to learn more about microorganisms. Microorganisms are numerous, and they come in many shapes and sizes.

Bacteria are a large group of unicellular prokaryotic microorganisms. A few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals. Archaea are single-celled microorganisms. Like bacteria, Archaea are prokaryotes and have no cell nucleus or any other organelles within their cells. Generally, archaea and bacteria are quite similar in size and shape however archaea possess genes and several metabolic pathways that are more closely related to those of eukaryotes. Viruses are sub-microscopic infectious agents that are unable to grow or reproduce outside a host cell. Microbiologists debate whether or not viruses are living organisms. They do not meet all the criteria used in the common definitions of life, however, viruses have genes and evolve by natural selection.

Fungi are eukaryotic, heterotrophic organisms. The majority grow as multicellular filaments called hyphae forming a mycelium but some fungal species grow as single cells. Fungi that are largely invisible to the naked eye are classed as microorganisms. Yeasts, moulds and mushrooms are examples of fungi. Algae include many single-celled organisms that are also considered protozoa, such as Euglena. Blue-green algae are in fact bacteria that obtain their energy through photosynthesis. They are generally, and more correctly, referred to as cyanobacteria.

Protozoa are mostly single-celled, motile protists that feed by phagocytosis, though there are numerous exceptions. Examples of protozoa include Euglena, Amoeba, Paramecium and Toxoplasma. Protists are a diverse group of eukaryotic microorganisms. Protists were traditionally subdivided into the one-celled animal-like protozoa, the plant-like protophyta (mostly one-celled algae), and the fungus-like slime molds and water molds. These groups have been replaced by phylogenetic-based classifications but are still used as informal names for describing the various protists.

Microbiology encompasses both prokaryotic and eukaryotic microorganisms but the majority of microbes are prokaryotes. Prokaryotes are a group of organisms that do not have a membrane-bound nucleus; they do not possess a nuclear membrane or nuclear envelope. They have DNA but the DNA is not enclosed in a membrane or envelope. In addition, they do not possess other membrane-bound organelles. Most are unicellular, but a few prokaryotes such as Myxobacteria have multicellular stages in their life cycles. The prokaryotes are divided into two domains: the bacteria and the archaea. Eukaryotes are defined as possessing a nuclear membrane enclosing their nucleus. Many eukaryotic cells also contain other membrane-bound organelles such as mitochondria, chloroplasts and Golgi bodies. Animals, plants, fungi and protists are eukaryotes.