The basic physics behind how rockets work! (plus a special announcement) Perimeter Institute: http://www.pitp.ca VomitPhysics video: http://www.youtube.com/watch?v=T7JLXg7yGx0 "Milkman" by freddiew: http://www.youtube.com/watch?v=1eFDra1XimA&list=PL627F181E0CB37E19&index=2&feature=plcp Bottle rocket video: http://www.youtube.com/watch?v=I5En8uBdKM4 ... https://www.youtube.com/watch?v=XwaGW-x7hS0

Thanks to the Heising-Simons foundation for their support: https://www.hsfoundation.org (their COVID-19 grants: https://www.hsfoundation.org/grants/covid-19-response-grants/ ) Check out https://aatishb.com/maskmath to explore and for references. This video is about how masks (whether surgical, or N95, or cloth) are counterintuitive and actually work much better epidemiologically than one might expect. Masks do double-duty, and the fraction of interactions with masks is much higher than the fraction of people wearing masks, so partially adopted, partially effective masks are able to reduce the basic reproduction number surprisingly well. REFERENCES: Aatish’s detailed writeup on github: https://github.com/aatishb/maskmath/blob/master/model/mathmodel.ipynb Amid the Coronavirus Crisis, a Regimen for Re-entry: https://www.newyorker.com/science/medical-dispatch/amid-the-coronavirus-crisis-a-regimen-for-reentry Face Masks Against COVID-19: An Evidence Review https://www.preprints.org/manuscript/202004.0203/v3 Mask FAQ Test Results: https://www.maskfaq.com/test-results The Effect of Mask Use on the Spread of Influenza During a Pandemic: https://onlinelibrary.wiley.com/doi/full/10.1111/j.1539-6924.2010.01428.x Calibrated Intervention and Containment of the COVID-19 Pandemic: https://arxiv.org/ftp/arxiv/papers/2003/2003.07353.pdf Cloth Mask Breathability and Filtration Efficiency Technical Report: https://static1.squarespace.com/static/5e8126f89327941b9453eeef/t/5f2c4463a5c9f75a38d2b26f/1596736614213/N95DECON_cloth_mask_breathability_filtrationtechnical_report_v1_200804.pdf What kind of mask should I be wearing to protect against COVID-19? http://built-envi.com/what-kind-of-mask-should-i-be-wearing-to-protect-against-covid-19/ Masks for all? The science says yes. https://www.fast.ai/2020/04/13/masks-summary/ The Real Reason to Wear a Mask: https://medium.com/the-atlantic/the-real-reason-to-wear-a-mask-e6405abbc484 Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics Link to Patreon Supporters: http://www.minutephysics.com/supporters/ MinutePhysics is on twitter - @minutephysics And facebook - http://facebook.com/minutephysics And Google+ (does anyone use this any more?) - http://bit.ly/qzEwc6 Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute! Created by Henry Reich ... https://www.youtube.com/watch?v=Y47t9qLc9I4