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, about 4 feet long, and weighs 14.7 pounds to represent the force of our atmosphere. This globe with "14.7" makes it more fun for kids! Post-Printing Printed in white ABS. First had the model in an acetone vapor bath for 30 minutes, cured overnight, then again for another 30 minutes. Used Sharpie markers to color the model and coated with colored acetone/abs paint (except on the red because it kept turning orange?). Took forever, and definitely needed better ventilation. Standards NGSS Overview and Background Ocean of Air This activity introduces students to the concept of a fluid and proves that air takes up space, has mass, and exerts pressure. Before the activity, students were introduced to Mass vs. weight, particles (especially molecules), and phases of matter. Students work in small groups of 3-5. Lesson Plan and Activity lesson summary This lesson starts with information about what the atmosphere is, its gases, and atmospheric pressure. Staff carry around pressure bars for students to feel the weight of 14.7 lbs, telling them that's equivalent to the force on each eyeball 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 turns pumping air out. Adults assist by making 20 more pumps! As air is removed, the air inside the marshmallow expands for a few seconds before returning to equilibrium with the jar and shrinking back down. Students make observations and predictions, then twist the valve. Air rushes in, crushing the marshmallow. All marshmallows are placed on the scale again, showing a lower mass from the air leaving (about 0.12 grams per six marshmallows!). This lesson is fun for students and reinforces science about our atmosphere and gas as a fluid with proper follow-up. Materials Needed Teacher: Bell jar apparatus with syringe pump to demonstrate 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)