INPUT ARTICLE: Article: To ensure you build the best and safest catapult, find durable and strong materials to withstand the extreme forces your catapult will use when shooting objects. There are a great many materials you could use in the construction of your catapult, but at minimum you will need: Broomstick or crank Padding Plywood (1/4" to 1/2" thick, 15" by 18 and 1/2") Rope (strong, stretchy preferred,like kernmantle rope) Screws or bolts Weights (optional) Wood (preferably non-flexible, like oak wood) If using 2x4 planks collect: two pieces at 36", one piece at 30", four pieces at 15", and one piece at 18" Since your catapult utilizes such powerful forces to eject its payload, you will need a strong and sturdy platform for launching as well as a strong and stable foundation. Poor foundation can throw off your aim or cause your catapult to fail. Torsion catapults, which is the technical name for a normal catapult, have historically been built with heavy, reinforced sides, as these would allow for heavier payload, greater tensile force, and greater stability. For the base of this catapult, you will use a 2x4 base supported with plywood triangles. To prepare your plywood supports, take one rectangular piece of plywood 1/4" to 1/2" thick, 15" by 18 and 1/2", and cut it diagonally into two equal triangles. Traditionally, spruce or fir wood were used for the throwing arm, as these woods were light and strong. Consult your local lumberyard to see if these are an affordable option and, if not, ask for some alternatives, two of which follow: Thick PVC pipe Metal pipe (lightweight, durable) You will need rope torsion to provide the launching force for your catapult. The more twists, the greater the torque, the more power your catapult will have. The amount of torsion (twisting) you can achieve is limited only by your strength and the strength of the materials you've used in making your catapult. To make your torsion handles, take a broomstick and cut into two 15 inch segments.

SUMMARY: Gather the materials. Contemplate base and weights. Cut your plywood supports. Choose the right material for your throwing arm. Cut your torsion handles.

INPUT ARTICLE: Article: First degree burns are the most common, and happen as a result of light scalding, brief contact with hot items, and the sun. The damage is only on the most superficial or outer layer of the skin.They will likely appear red, slightly swollen, and may or may not be slightly painful. Treat your first degree burn at home, since there is usually no need for expert medical attention. The outermost layer of skin has the ability to heal itself with care and time. First degree burns are classified as 'minor burns' and should be treated as such. Sometimes you may get an extensive first degree burn, such as a full body sunburn, but this does not need medical attention. Your skin might also appear blotchy, blisters will form, and the pain will be much more intense. Second degree burns come from brief contact with incredibly hot things (boiling water, for example), extended contact with hot items, and prolonged exposure time in the sun. Unless your second degree burn is on your hands, feet, groin, or face, treat it like a minor burn. If you have blisters, don't drain them. If the blister is drained, keep it clean by rinsing with water and swabbing with antibacterial ointment. You can also cover the ointment on the skin with a bandaid or another dressing. This dressing needs to be changed daily. A second degree burn burns through two layers of your skin. If your second degree burn is wider than three inches, covers your hands, feet, joints, or genitals, or doesn't heal over several weeks, then you should call your doctor for medical help. Third degree burns are the most serious and need immediate medical attention. These happen when extended exposure to a hot object burns through all three layers of your skin, sometimes causing muscle, fat, and bone damage. The burns will look leathery and have a white or black appearance. The pain can vary depending on the level of damage to the nerves in the skin layer (pain receptors). These burns can look "wet" because of the rupture of the cells and protein leakage. Third degree burns are always classified as a major burn and need treatment from a doctor as soon as possible. These are 'burns' that occur when your skin is exposed to low temperatures, like snow or ice, for an extended period of time. The area will look bright red, white, or black and will have a strong burning sensation as the skin is rewarmed. A low temperature "burn" is still considered a burn because it damages the skin's tissue layers. Treat low-temperature burns as major burns in most cases, and get medical help for treatment. Rewarm the skin in 37C/98.6F to 39C/102.2F water immediately after exposure. Chemical burns are another type of burn caused by skin contact with harmful chemicals that damage the skin layers. These types of burns will probably appear in the form of red patches, a rash, blisters, and open sores on your skin. Your first step is always to determine what caused the burn and to call poison control immediately. Contact a poison control center immediately if you believe you've suffered a chemical burn. Care must be taken to neutralize and isolate the spread of the chemical. Irrigate chemical burns with lots of water, however, avoid water if exposed to dry lime or elemental metals (such as sodium, magnesium, phosphorus, lithium etc.) as these can react with water and cause more injury.

SUMMARY:
Figure out if you have a first degree burn. Know if you have a second degree burn. See if you have a third degree burn. Check low-temperature burns. Determine if you have a chemical burn.