Thursday, March 19, 2020

Make Your Own Flash Paper (Nitrocellulose)

Make Your Own Flash Paper (Nitrocellulose) If youre a chemistry enthusiast with an interest in fire or history (or both), you probably ought to know how to make your own nitrocellulose. Nitrocellulose is also known as guncotton or flashpaper, depending on its intended purpose. Magicians and illusionists use flash paper for a fire special effect. The exact same material is called guncotton and may be used as a propellant for firearms and rockets. Nitrocellulose was used as a film base for movies and x-rays. It may be mixed with acetone to make nitrocellulose lacquer, which was used on automobiles, aircraft, and musical instruments. One unsuccessful use of nitrocellulose was to make faux ivory billiard balls. The camphored nitrocellulose (celluloid) balls would sometimes explode upon impact, producing a sound much like that of a gunshot. As you might imagine, this didnt go over well in gunslinger saloons with pool tables. Its unlikely you will want to make your own exploding billiard balls, but you might want to try nitrocellulose as a model rocket propellant, as flash paper, or as a lacquer base. Nitrocellulose is extremely easy to make, but be sure to read through the instructions carefully before proceeding. As far as safety goes: Any protocol which involves strong acids should be performed by qualified persons wearing proper safety gear. Nitrocellulose cannot be stored for long periods of time, as it gradually decomposes into a flammable powder or goo (which is why many old films have not survived to the present day). Nitrocellulose has a low autoignition temperature, so keep it away from heat or flame (until you are ready to activate it). It does not require oxygen to burn, so once it ignites you cannot put out the fire with water. With all that in mind, heres how you make it. Key Takeaways: Make Nitrocellulose or Flash Paper Nitrocellulose is a highly flammable polymer. It is also known as flash paper, guncotton, or flash string.All you need to do to make nitrocellulose is treat cellulose with nitric acid or any other strong nitrating agent. The cellulose can come from paper, cotton, wood, or other plant matter.Nitrocellulose was first made by Alexander Parkes in 1862. This was the first man-made plastic, which was named Parkesine.While useful as a plastic, nitrocellulose is equally popular for its flammability. Flash paper burns almost instantaneously and leaves no ash residue. Nitrocellulose Materials Christian Friedrich Schà ¶nbeins procedure has been widely used. It calls for 1 part cotton to 15 parts acid. concentrated nitric acidconcentrated sulfuric acidcotton balls (almost pure cellulose) Nitrocellulose Preparation Chill the acids below 0 °C.In a fume hood, mix equal parts nitric and sulfuric acid in a beaker.Drop cotton balls into the acid. You can tamp them down using a glass stirring rod. Dont use metal.Allow the nitration reaction to proceed for about 15 minutes (Schà ¶nbeins time was 2 minutes), then run cold tap water into the beaker to dilute the acid. Allow the water to run for a while.Turn off the water and add a bit of sodium bicarbonate (baking soda) to the beaker. The sodium bicarbonate will bubble as it neutralizes the acid.Using a glass rod or gloved finger, swirl around the cotton and add more sodium bicarbonate. You can rinse with more water. Continue adding sodium bicarbonate and washing the nitrated cotton until bubbling is no longer observed. Careful removal of the acid will greatly enhance the stability of the nitrocellulose.Rinse the nitrated cellulose with tap water and allow it to dry in a cool location. Shreds of nitrocellulose will burst into flame if exposed to the heat of a burner or a match. It doesnt take much (either heat or nitrocellulose), so dont get carried away! If you want actual flash paper, you can nitrate ordinary paper (which is primarily cellulose) in the same manner as cotton. Chemistry of Making Nitrocellulose Nitrating cellulose proceeds as nitric acid and cellulose react to produce cellulose nitrate and water. 3HNO3 C6H10O5 → C6H7(NO2)3O5 3H2O Sulfuric acid is not required to nitrate the cellulose, but it acts as a catalyst to produce the nitronium ion, NO2. The first order reaction proceeds via electrophilic substitution at the C-OH centers of the cellulose molecules.

Monday, March 2, 2020

ESL Conversation Lesson Plan on Creating a New Society

ESL Conversation Lesson Plan on Creating a New Society This classic conversation lesson plan is based on the idea of creating a new society. Students must decide which laws will be followed and how many freedoms will be allowed. This lesson works well for ESL students of most levels (except beginners) because the subject brings out many strong opinions. Aim: Building conversation skills, expressing opinionsActivity: Group activity deciding on the laws for a new societyLevel: ​Pre-intermediate to advanced Lesson Plan Outline Help activate vocabulary by asking students which laws they admire most and least in their own country - and why.Divide students into groups of 4 to 6. Try to include as many different personalities as possible in each group (to provide for more stimulating discussion!).Explain the following situation to the class: A large area of your country has been set aside by the current government for the development of a new nation. This area will include an invited international community of 20,000 men and women. Imagine that your group has to decide the laws of this new country.Distribute the worksheet and ask students to discuss the questions.Answer the worksheet as a class - ask the opinions of each group and leave ample time for discussion of differing opinions.As a follow-up activity, the class could discuss which laws and customs they would like to change in their own country. Scenario and Accompanying Questions Populate Ideal Land A large area of your country has been set aside by the current government for the development of a new nation. This area will include an invited international community of 20,000 men and women. Imagine that your group has to decide the laws of this new country. Questions to Ask Which political system will the country have?What will the official language(s) be?Will there be censorship?What industries will your country try to develop?Will citizens be allowed to carry a gun?Will there be the death penalty?Will there be a state religion?What kind of immigration policy will there be?What will the educational system be like? Will there be compulsory education to a certain age?Who will be allowed to marry?