Self-Carving Exploding Jack o Lantern Demonstration

Self-Carving Exploding Jack o' Lantern Demonstration The self-carving pumpkin uses a chemical reaction to cause an explosion inside a pumpkin, forcing out the pumpkin pieces of a jack-o-lantern face (with an accompanying bang and fire). You can perform this popular chemistry Halloween demonstration yourself: Self-Carving Exploding Pumpkin Materials 50 ml hydrogen peroxide (H2O2)20 ml water~7 pea-sized chips of calcium carbide (CaC2)Â  cat food or tuna canoven mitt (to avoid getting burned)piezoelectric sparker Make a Self-Carving Pumpkin Carve a medium pumpkin with a simple face. Triangles, circles, squares and ovals are good choices. Re-insert the face pieces, making sure they can move easily out of the pumpkin. If the pumpkin has thick flesh, you may wish to cut away the back of the pieces so they are lighter/weaker.Poke or drill a small hole in the back of the pumpkin so you can insert the wire sparker. Insert the sparker and test it to make sure it works.Pour the peroxide in the pumpkin. (an optional step in some descriptions)Put the water in the cat food or tuna can and set the can in the pumpkin.Drop the calcium carbide chips into the water and replace the lid of the pumpkin. Allow about a minute for the acetylene to build up.Be sure the face of the pumpkin is facing away from you and that your audience is a safe distance from the demonstration. You may wish to wear ear protection. Goggles and a lab coat are recommended. While holding down the lid of the pumpkin (with an oven-mitted hand), spark the sparker. How the Self-Carving Pumpkin Works In 1862 Friedrich WÃ ¶hler discovered calcium carbide and water would react to form flammable acetylene gas and calcium hydroxide: CaC2 2 H2O → C2H2 Ca(OH)2 This reaction is used in the commercial manufacture of acetylene and for carbide lamps, which are used by miners in some areas. Safety Precautions This demonstration is best performed by a chemistry teacher or other adult experienced with chemicals or pyrotechnics. It is not a suitable project for kids to try. Youll likely need to order calcium carbide through a chemistry or educational supply store or else buy it online. Remote ignition of the acetylene is safer than holding the pumpkin and striking a sparker, though youll want to secure the lid of the jack-o-lantern so that it wont simply blow off, leaving your pumpkin uncarved. If the pieces of the face are not loose, either the pumpkin will explode or else the explosion will be contained and the pumpkin will be uncarved. Safe Self-Carving Pumpkin This is also a safe version of this project which uses carbon dioxide gas to blow out the jack-o-lantern face. Although carbon dioxide can be compressed to where it explodes, using a plastic bag to contain the gas provides enough pressure to produce the desired effect without the risk of injury.

Old World Monkeys - Cercopithecidae

Old World Monkeys - Cercopithecidae Old World monkeys (Cercopithecidae) are a group of simians native to Old World regions including Africa, India and Southeast Asia. There are 133 species of Old World monkeys. Members of this group include macaques, geunons, talapoins, lutungs, surilis, doucs, snub-nosed monkeys, proboscis monkey, and langurs. Old World monkeys are medium to large in size. Some species are arboreal while others are terrestrial. The largest of all Old World monkeys is the mandrill which can weigh as much as 110 pounds. The smallest Old World monkey is the talapoin which weighs about 3 pounds. Old World monkeys are generally stocky in build and have fore limbs that are in most species shorter than hind limbs. Their skull is heavily ridged and they have a long rostrum. Almost all species are active during the day (diurnal) and are varied in their social behaviors. Many Old World monkey species form small to medium sized groups with complex social structure. The fur of Old World monkeys is often gray or brown in color although a few species have bright markings or more colorful fur. The texture of the fur is not silky nor is it woolly. The palms of the hands and soles of the feet in Old World monkeys are naked. One distinguishing characteristic of Old World monkeys is that most species have tails. This distinguishes them from the apes, who do not have tails. Unlike New World monkeys, the tails of Old World monkeys are not prehensile. There are a number of other characteristics that distinguish Old World monkeys from New World monkeys. Old World monkeys are comparatively larger than the New World monkeys. They have nostrils that are positioned close together and have a downward facing nose. Old World monkeys have two premolars that have sharp cusps. They also have opposable thumbs (similar to the apes) and they have nails on all fingers and toes. New World monkeys have a falt nose (platyrrhine) and nostrils that are positioned far apart and open either side of the nose. They also have three premolars. New World monkeys have thumbs that are in line with their fingers and grip with a scissor-like motion. They do not have fingernails except for some species that have a nail on their largest toe. Reproduction: Old World monkeys have a gestation period of between five and seven months. Young are well developed when they are born and females usually give birth to a single offspring. Old World monkeys reach sexual maturity at about five years of age. The sexes often look quite different (sexual dimorphism). Diet: Most species of Old World monkeys are omnivores although plants form the larger portion of their diet. Some groups are almost entirely vegetarian, living on leaves, fruit and flowers. Old World monkeys also eat insects, terrestrial snails and small vertebrates. Classification: Old World monkeys are a group of primates. There are two subgroups of Old World monkeys, the Cercopithecinae and the Colobinae. The Cercopithecinae include primarily African species, such as mandrills, baboons, white-eyelid mangabeys, crested mangabeys, macaques, guenons, and talapoins. The Colobinae include mostly Asian species (although the group does include a few African species as well) such as black and white colobuses, red colobuses, langurs, lutungs, surilis doucs, and snub-nosed monkeys. Members of the Cercopithecinae have cheek pouches (also known as buccal sacs) that are used to store food. Since their diet is quite varied, Cercopithecinae have non-specialized molars and large incisors. They have simple stomachs. Many species of Cercopithecinae are terrestrial, although a few are arboreal. The facial muscles in Cercopithecinae are well developed and facial expressions are used to communicate social behavior. Members of the Colobinae are folivorous and lack cheek pouches. They have complex stomachs.