"Help! My child is choking!" This is one of the most terrifying cries heard by many of the nation's 911 telephone operators. Why are so many children involved in choking incidents? The culprits are usually small blocks, Legos, Construx, K'Nex, jewelry, buttons, bells, beads, coins, and a host of other small toy parts which toddlers put in their mouths, and may ultimately get stuck in their throats.

The U.S. Consumer Product Safety Commission (USCPSC) has implemented a "choking" test for toys and a recall system to beef up their already high safety standards. In addition, all toy packaging boxes are required to display an age recommendation label for consumers. Unfortunately, as can be reported by the USCPSC, many products which are dangerous for small children are overlooked by cautious parents and fall into the hands of curious tykes. In fact, of the 171 toy-related deaths reported from January 1, 1988 to September 30, 1994, 93 of them (more than half!) were caused by choking. During this period, many more choked on toys but were saved by the Heimlich Maneuver.

Because there is no fool-proof way to prevent children from choking on toys, it is essential that scientists continue to develop and promote new safety measures. Otherwise, children will continue to die. Through careful contemplation, discussion and research, perhaps the answer to this problem is a rather simple one: give the child a reason not to put these toys into his or her mouth.

One precaution which could easily be taken would be to manufacture toys which have an unpleasant taste while at the same time maintaining their playful quality. Obviously, toys that smell, look, or feel bad will cause a decline in product sales, making both businessmen and children alike very unhappy. If one were to alter the taste of these toys to a rather pungent flavor, children would think twice before using their big brother's Legos for chew toys.

Taste is a complicated process in which series of chemical reactions must take place first. The taste buds relay chemical and electrical messages throughout the mouth before the final signal of flavor is sent to the brain. Taste actually begins when a flavor comes in contact with the receptor cells of the taste buds, located on the papillae throughout the mouth. For a food to be tasted it must contain fat or be moistened (by saliva). The molecules dispatch signals to the receptor cells. They send messages back and forth. These signals are then sent to the basal cells. Here, the signs switch the electrical charge and induce a discharge of chemical stimulants. These chemical stimulants are then received by the glossopharyngeal nerve at the back of the tongue which carries the signals to the thalamus.

We become aware of the taste when the brain interprets the messages of sweet, bitter, sour, or salty tastes. Salty and sweet flavors easily circulate through the taste bud receptors found on the tip of the tongue. The spicy bitter flavors, which we will primarily be dealing with, inflame sensory nerves and enhance other flavors. A person's acceptance of flavors is developed both psychologically by parents and determined genetically. While young children don't have a fully developed sense of receptors, they will reject one substance over another. However, a substantial Scoville heat quantity must be used.

Flavor is measured according to its "bite" or heat. The heat is measured in Scoville units. The FDA uses a standard Scoville heat test to document all foods. It takes the foods and brings them down to the threshold of their flavor. The threshold refers to the initial point where a taste other than sugar is recognized. By bringing it down to that point, scientists can then increase the "bite" as high or low as they want.

In addition to searching for a spicy flavor, it was necessary to set up other standards. The substance would have to be relatively clear and not too aromatic. It should also be relatively inexpensive, accessible, and durable. It has to be non-carcinogenic and not caustic, and FDA approved. It must also be soluble in water (or alcohol, which is how we chose to dilute it).

We scrambled in vain through spice books, flavor books, and chemistry books. Through extensive research and a cross reference of all bitter flavors to our set standard, we came up with ten possible solutions. A rather likely substance, was quinine (C20H24N202) since it offered such a bitter flavor to tonic water. But further research revealed that it was an extremely expensive substance, used to cut heroin. We were told that keeping this product in a laboratory without its being stolen is almost impossible.

We also examined both natural and artificial extracts. Mustard oil seemed to be a good candidate until we discovered that one whiff could cause the capillaries in the nose to burst resulting in a nose bleed. Mace, unfortunately, is a hallucinogenic which would not go over well with the Food and Drug Administration (FDA). Cinnamon, which is used to create spicy flavors, causes topical burning when applied to the skin. Licorice is too sweet while lemon grass and lime juice are too aromatic. Horse-radish was too strong and would cause eyes to tear. Cardamon is mainly used in bakeries for flavor.

After heavy debate, we decided to test what we found to be the five best flavors: ginger, black pepper, capsicum, turmeric, and quassia. We would then consider the advantages and disadvantages of each and see if we could work around them. Because all of these experimental substances are in their pure state, it was important to find a solvent to dilute them. In considering the perfect solvent, it would have to be clear, liquid, inexpensive, volatile, and non-aromatic. We considered water, ethyl alcohol, and isopropyl alcohol. Initially, we felt water would best. However, it was not volatile and took too long to evaporate. Ethyl alcohol was volatile, but had a bad taste which we did not want to blend with our flavors.

It turned out that isopropyl alcohol (C2H8O) was our best bet. It was clear, relatively neutral in smell, inexpensive, and most importantly - extremely volatile. While consumption of large amounts of this could cause flushing, headache, dizziness, mental depression, nausea, and vomiting, minute doses after evaporation should have no effect on children.

With five flavors to be tasted, a suitable agent to dilute them, and some small toys to try them on, it was time for the hands-on experimentation to begin. The MAIN OBJECTIVE of our experiment was to find a flavor that would cause a burning effect in the mouth without causing injury.

First, we made uniform solutions of our flavors to be tested. On a sensitive electronic gram scale we measured and recorded the initial weight of all the glass capsules to be used in the experiment. With a standard weight set, we continued to make the various solutions. Using a medicine dropper we added .1 grams of flavor to its labeled jar and 9.9 grams of isopropyl alcohol. This solution was one part per hundred or 1% flavor.

This procedure was followed for all five flavors resulting in 10 grams of a 1% solution of each flavor to test. Next, we decided to taste each of the flavors with a paper swab. In tasting them, we used a spatial screening test, in which one takes a swab of the substance and places it on certain parts of the tongue. The standard localized areas are at the tip of the tongue (which we wanted), the sides of the tongue, and the back of the tongue.

What we realized was that the different flavors affected different areas in different ways. What we had hoped for was to have a major reaction at the tip of the tongue. The actual bite that is experienced from each flavor is unique and difficult to describe, ranging from a mild sharp to sweet sharp. This experiment is based upon individual taste preferences; there is no right or wrong flavor, just preference! So, we took our two favorite flavors, capsicum and black pepper, and combined them into solution at 1% each. We were hoping for an added kick and a nice blend of the two flavors. That was a bad idea. It was awful! The whole flavor backfired! It was too strong and had a horrible flavor and smell.

After eliminating certain flavors, we moved on to the second part of the experiment, which was to double the bite of each flavor in solution. This was done by adding .2 grams of flavor to 9.8 grams of alcohol. This 2% flavor solution set our "mouths aflame" and kept them "smoldering" for the rest of the day. We decided that the 1% solution was best. And once again, a startling revelation was made. We realized that not only was the bite of the flavor important, but also a longer duration of the bite was necessary. The initial bite in the 1% solution was perfect, but in a second it vanished.

Through research we discovered that in order to make a flavor "last forever," it was necessary to add a lactone. We were able to acquire a bottle of gamaundecalactone. Lactones have a rather peachy smell and taste to them. So we created two solutions, one solution of .1 grams capsicum, .1 grams lactone, and 9.8 grams of alcohol.

The second solution substituted black pepper for capsicum. Well, that did it! The two final flavors were now perfect-tasting. Each one gave a desirably annoying spicy flavor which lasted long enough to have an impact and short enough to prevent major damage. The lactone also makes the flavor solution more durable on the toy.

But before we tell you which one we chose, let us tell you why we eliminated the other three: ginger, quassia, and turmeric. Ginger was rejected because of taste. It just wasn't what we had hoped it to be. It had a rather disagreeable smell and not the right type of bite wanted. It was also much too sweet. Also, ginger is not particularly soluble and is relatively expensive at $33.50 a pound. Though quassia was the cheapest at $5.00 a pound, it had a mild, sharp taste and a cooling effect on the tongue. We ruled out turmeric because of the flavor and the color. It had a thick bright yellow appearance which was unacceptable. It is interesting to note that turmeric is used as a cancer inhibitor.

Having to choose between capsicum and black pepper, we chose capsicum. Though black pepper had the perfect taste, the disadvantages were significant. It settled out of solution easily and the scent of the pepper was unpleasant. It was pungent and sharp and did not tone down with the peachy smell of the lactone. It was also expensive at $38.60 a pound and commercially impractical.

Capsicum, or a cayenne pepper, met all of our standards. The final product, Flavor-X, would be in a solution of 1% capsicum, 1% lactone, and 98% alcohol. Besides having a great taste, it had a good color and a pleasant smell. It was durable, accessible and affordable at $10.40 a pound. In addition, it might be good to note that when used in large quantities, it is a natural pain-killer. After pepper is eaten the burning sensation in the mouth is relieved by the release of endorphins. The capsaicin, which is very spicy, causes the release of Substance P, which signals pain signals from the nerves. The main ingredient giving this pepper its kick is a chemical called capsaicin (C18H27NO3).

Another step in manufacturing a product is the testing. On a professional level, once a flavor has been developed, it has to be tested by a panel of judges, who answer a questionnaire. In most cases, it is fellow scientists in the lab or a panel of 15 to 20 volunteering adults. We used our families, especially our little brothers and sisters. They all got a little jolt, but no harm was done. We had found the perfect solution.

One problem that we frequently thought about was the potential of an allergic reaction. This substance would have to be hypoallergenic. An allergy specialist felt that there would be no problems with the products used because people are generally not allergic them. We then considered the sensitivity of different taste buds. We feared that a person with very sensitive taste buds might be injured by such a strong flavor. So we tried to look for an antidote. Casein, a protein found in milk, milk chocolate, nuts and beans, relieves the burning sensation brought on by spicy foods. If one were to find the product very painful, a simple glass of milk would relieve the pain.

Durability was also a problem. But we solved that by adding a lactone and applying it to porous objects. In toys that had a special wax or high-gloss coating on them we sanded down and removed that layer. We wanted to develop a high-gloss lacquer for the toys that would combine the flavor into it so it could become part of the manufacturing process. We didn't have the resources to try this, so we applied the substance at home with an atomizer.

In order for a toy to retain the flavor, it must be applied in solution. The solution then permeates the pores of the plastic, wood, etc. This permeation causes the flavor to linger. The lactone gives added durability. From its design, it can easily be applied with a spray bottle at home or at the time of manufacture. That would depend upon which method would be more efficient.

For the permeation of one inch by half inch wooden blocks, we first washed them in an anti-bacterial soap and let them dry. We then continued to spray them with alcohol to further rid them of germs. A medicine dropper was used to saturate them. (Another discovery we made was that we didn't have to apply the product to each side of the toy. From tasting them, we realized that one or two sides of the figure would be more than enough to give it the right bite.) With the medicine dropper we added 6 drops of our flavor to the top side of the toy. When the children placed the object in their mouths, they immediately spat it out. This response made our project a success!

We had finally reached the conclusion of our experiments, and it was a great feeling to realize all the other discoveries we had made. The research went beyond reading books, performing experiments, and writing reports. We had the amazing opportunity to conduct our experiments in a professional laboratory next to real scientists. We learned about controls, flavors, the flavor process, taste process, anatomy of the tongue, etc. We learned how to research, how to question, and what to question.

We all realized that if we want something done, we have to pursue it for ourselves. We found ways to open new doors when all the others had been closed in our faces. It taught us how to budget our time wisely and how to communicate with people. We learned how to be a team: because as a team we worked together, we laughed together, we fought together, we lost together, and we triumphed together. And that is the most important lesson of all! u