Origin of the three types of bee. The workers build three types of cell. Worker cells predominate. Drone cells are fewer and slightly larger. Queen cells are still larger and quite different in shape. They are made singly and often project from the base or surface of the comb.

The queen lays indiscriminately in all these cells but the eggs in the drone cells are unfertilised and develop into males. The eggs in the worker and queen cells are fertilised and develop into females. However, the queen is fed a diet different in quantity and quality from the workers diet and, as a result, develops into the only fertile female.

The queen produces hormone-like substances called pheromones or queen substance. These play a vital part in suppressing the egg-laying propensities of the workers. Wherever the queen goes, she is followed by a crowd of workers who feed her and lick her body with their probosces and so absorb the pheromones.

Swarming. When the size of the colony reaches a certain stage, usually in Spring or Summer when the nectar flow is at its greatest, the queen and a great many workers leave the hive in a swarm. The swarm comes to rest in a great cluster on a tree branch or similar situation. Scout bees, who may have left the hive some days before, seek out a suitable situation for a new nest and return to the swarm and communicate this information, whereupon the whole swarm moves off to the new site. Meanwhile, in the old hive, one of the new queens hatches out, mates, and takes over the colony that is left.

D G Mackean is the author of GCSE Biology, IGCSE Biology, and many other Biology text books. He has a site of Biology Teaching Resources at http://www.biology-resources.com which includes a bank of experiments for teachers, sample PowerPoint presentations, and many biological drawings

For years I taught about density as well as the properties of carbon dioxide, though never at the same time. Why it took so long to put the two together, I'll never know. Here then, are a few demonstrations involving the density of carbon dioxide gas and a flame. These should be done by adults or under careful adult supervision as there is a potential of fire hazard.

I suggest starting by showing that air and carbon dioxide have different characteristics. Hold a lit candle in a glass for a few moments. It keeps burning. Now place a small amount of baking soda in the glass and pour in a bit of vinegar. What do the kids see happening (bubbles) and what do they think is happening (gas is produced)? Now lower the lit candle into the glass and it will go out instantly (the gas does not support the burning of the candle).

For the next part of the demonstration you will need several candles of different height. You will want as many different heights as possible so some candles may be broken, some placed on supports such as candlestick holders, inverted coffee cups, etc. I always hold these candles in place by lighting one and allowing the hot wax to drip onto the surface where I want a candle to be placed. I then place the bottom end of the candle in the wax and allow the wax to harden. The candle will be "glued" in place by the cooling wax. I have the candles / supports placed in the upright aquarium so that one corner remains open.

Now, light all of the candles. The effect should be quite pretty, but that is not the purpose. Place one cup of baking soda in the free corner of the aquarium. To this add two cups of vinegar. The familiar bubbling will occur. By watching the candles, something intriguing will be seen. They will go out, one by one, from the candle closest to the aquarium bottom to the uppermost candle. The reason? The carbon dioxide is more dense than air, therefore it rests below the air in the aquarium. Since it is continually produced, it pushes the air out of the aquarium so that it can remain below it. If enough vinegar / baking soda are added, the aquarium will become brim full of carbon dioxide. To prove this just light another candle and slowly lower it into the aquarium. It will extinguish itself once it gets below the aquarium's opening. In fact, the carbon dioxide will rest in the aquarium for quite some time, especially if the room is still.

Another demonstration to try is to make a long trough out of V-shaped aluminum foil and use it as a guide for pouring carbon dioxide. Place a candle in a candlestick holder and light it. Place some baking soda and vinegar in a large bottle and let the bottle fill with carbon dioxide. Now, hold the aluminum foil trough so that one end is just above the candle flame. The other end is held higher. If water was added to the trough, it would pour down and extinguish the candle. We are going to do this with the carbon dioxide instead. "Pour" the carbon dioxide from the bottle into the higher end of the trough. The candle flame will flicker and usually extinguish at the lower end of the trough. Why? (The carbon dioxide, being more dense than air, actually does pour down the trough. Once it reaches the other end, it pours out of the trough and over the candle flame. Since the gas does not support combustion, the flame flickers and goes out.) This should re-instill the idea that carbon dioxide is more dense than air, as well as the fact that carbon dioxide does not support combustion.

A final thought... if you have easy access to affordable dry ice, it can be used in place of the baking soda and vinegar. It really is just carbon dioxide gas cooled and compressed into solid form. If you handle it, be sure to use gloves and tongs as it can quickly and easily cause frostbite.

Until next time... keep having fun with science!

Thomas Smith owns and operates Wonder Workshops, an online supply mecca of retro toys, puzzles, puppets, magic tricks, books, novelties, and DVDs, all based in science, math, and problem solving. Tom also presents hands-on, mind-on science workshops for teachers and parents around the country. To find out more about the workshops and store, be sure to visit http://www.wonderworkshops.com You'll be glad you did!

DNA testing is becoming increasingly used to determine genetic links between individuals as a highly accurate and individual way of identifying people and their relationships with one another. The process itself is one carried out in advanced laboratories under the strictest of lab conditions to ensure no cross-contamination and improve result accuracy. As such DNA testing can be said to present with a high degree of accuracy any particular biological relationship that may exist, particularly in paternity disputes where samples of both the mother and the father are provided.

Preparing For the DNA Test and Collecting Samples

Normally a DNA testing kit is sent to the person who ordered the test by the company from whom the order was made. The test begins with samples being collected from everyone preparing to undertake the test. In most cases, that will mean the mother, the father (alleged) and the child concerned. Samples are taken by the way of oral swabs, which collect cheek cells which are then dried and passed on for testing. In order to prepare the sample, it is first important to make sure that the cotton of the swab never touches any other surface including your hands, and that you have a number of swabs for each person taking the test to ensure reliability in the end results. Press the swab into the inside of the cheek and behind the lips, as well as the tongue area in order to get as good as possible a sample from the mouth. Having left to dry for around an hour, the swab should be carefully sealed off before the collation and mailing process.

Testing the Samples

After all the samples have been collected and labelled accordingly, they should be sent off to the laboratory for the DNA testing analysis. At this stage, the samples will be individually examined and DNA will be extracted from within the cells present in the sample. The same will be done for both the other two parties to the test and the results of the DNA profiles will be compared.

The person analysing your results will be looking for a 50/50 split between your alleles, contained within the DNA, between those found on your mother and father. As you can only inherit genes already carried by one or both parents, no alleles can be present in the child's DNA that are not present in that of either parent. Naturally, this is where it becomes obvious when there is and is not a genetic link between those taking the DNA test. Further to that, the results are processed through the appropriate systems and a conclusion is reached, having covered 16 of the locus which are used as the template by which samples are matched.

Receiving the DNA Test Results

Once the DNA test is completed, the result will be sent to the participants via email, letter, fax or as otherwise agreed. The DNA test report should show the individual profile of each person that submitted a sample for the paternity test. Also the result should show the percentage probability of the stated relationship, for example in a DNA paternity test this is normally in excess of 99.99%.

There's no doubt about it - DNA testing is here to stay. Whilst most people are not very knowledgeable on how DNA paternity testing works, it is probably a good idea to gain some level of understanding given the way in which DNA testing is likely to continue to affect our lives over the coming decades. With growing calls for more extensive DNA databases and records for crime prevention, DNA testing and analysis looks set to remain at the forefront of the civil liberties/state interests debate.

Kevin Camilleri writes articles for dna paternity test. Other articles written by the author related to paternity testing, home paternity test and paternity test kit can be found on the net.

Are men and women different in their tastes of how to spend free time? Are teenagers different? Here's some background information that could be an interesting science fair project to help you find out. If you are not interested in doing a project, you could do this experiment for the fun of it.

Let's begin with some preconceived notions of what we think men and boys like to do. Sporting events of all kinds; car racing, football, baseball, basketball, hockey and wrestling would be among the favorites. Men like to male bond doing things like hunting, fishing, camping, playing golf, playing cards and other forms of gambling.

Some stereotypical diversions for girls and women might include visiting art galleries, spending time with book clubs, shopping and window shopping, charitable work and child care.

These gender-related avocations may seem a bit medieval and chauvinistic. Or are they? We will find out with an experiment to learn the truth.

Gather a list of all of the friends and family that you think would enjoy participating in the experiment. If you are doing a science fair project, make sure you quantify all of your data to make your presentation. Get a good mix of men and women, boy and girls. The more the merrier.

Structure a questionnaire listing activities like those mentioned above and add as many different activities that you can think of. If you wish to focus on high school students, for example, you may wish to include items like school social activities, school trips, athletic events, dances, lectures, seminars, field trips, after-school activities, home work and so on.

If you are working with adults, you might include luncheon meetings, parent-teacher activities, going to the playground with your children, and most anything that you wish to include. You should create a good mix of so called male and female oriented diversions.

It would be helpful to have as many as twenty people on your list, making certain that you have a representative number of people of different genders and age groups. Prepare your questionnaire and ask them to rate what they like on a scale of one to five, with one being something they really like, and five being something they never do.

Gather the finished data, reduce the figures, and come up with your answers. What have you found? Where your preconceived notions borne out? Or where you surprised with the results?

Mort Barish is co-founder of Terimore Institute, Inc. providing science fair projects for children in grades K-12 to help them successfully compete in science fairs. He has been creating educational materials for children and related graphic communications for almost fifty years. He is the author of seven books and has won numerous awards for his graphic presentations.