Atmospheric Pressure Bar end cap

thingiverse

This is a decorative end cap for Iron Atmospheric Pressure Bars. Each bar is 1 square inch at the end, is about 4 feet long, and weighs 14.7 pounds to represent the force of our atmosphere. This globe with "14.7" is just to make it a little more fun for the kids! Post-Printing Printed in white ABS. First had the model in an acetone vapor bath for 30 minutes, cured over night, than again for another 30 minutes. Used Sharpie markers to color the model, and coated with colored acetone/abs paint (except not on the red, because it kept turning orange??). Took forever, and definitely should have had better ventilation. Standards NGSS Overview and Background Ocean of Air Due to lesson plan copyrights of the educational organization I work for, I cannot post the full lesson plan, but I will summarize the experiment and trust my fellow educators to find the best way to work it into your class. This activity is designed to introduce students to the concept of a fluid, and prove that air takes up space, has mass, and exerts pressure. Prior to activity, students have been introduced to the concept of Mass vs. weight, particles (esp. molecules), and phases of matter. Students are in small groups of 3-5. Lesson Plan and Activity lesson summary This lesson begins with a front load of information about what the atmosphere is, the gases that make it up, and atmospheric pressure. Pressure bars are carried around by staff for students to feel the weight of 14.7 lbs, and are told there is the equivalent of that on each of their eyeballs right now! Students are then introduced to the experiment. After measuring the mass of all regular sized marshmallows together, students place one in each bell jar apparatus and take one pump each. Adults then assist by making 20 more pumps! As air is removed, the air inside the marshmallow causes it to expand for a few seconds, before it returns to equilibrium with the jar and shrinks back down to normal. Student make observations, and predictions, then twist the valve. Air rushes in, and crushes the marshmallow. All the marshmallows are placed on the scale again and we see a lower mass from the air leaving. (Six marshmallows usually have a difference of about 0.12 grams of air!) This lesson is a lot of fun for students and, with proper follow up, really reinforces the science of our atmosphere and gas as a fluid. Materials Needed Teacher: Bell jar apparatus with syringe pump to demo scale to find mass of all marshmallows (before and after) Per group: Bell jar apparatus with syringe pump Full sized Marshmallow (no organic or all-natural, they don't work.)