{"schema":"pubphys.bundle/1","record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"99e7fd4d30312903d30e54ca9be6b2f3bd1a6b9080d42a09b33ecc5f930cbb80","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":["ai:gpt-5.5"],"kind":"seed"},"parents":["789c7d183315a46ee00f9052588cb93807a0eeb32e5195844c24759e22c7b05a","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"a356e0a485679259e317976cb642a72551a3cf505e65cc2fd211047502eb3f75","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"mechanism","assisted_by":["ai:gpt-5.5"],"external_id":"fluid.drop-impact.air-splash-mechanism","kind":"phenomenon","literature_status":"contested","n":"2","parents":[],"plain":"A drop hitting a smooth dry surface in air throws off a thin sheet that breaks into droplets, but in thin enough air the same impact does not splash at all. How the air produces the splash is not agreed.","posed_since":"2005","precise":"A low-viscosity drop of radius $R \\sim 0.1\\,\\mathrm{cm}$ hitting a smooth dry solid at speed $V$ of a few hundred cm/s splashes at 1 atm but not below a threshold gas pressure $P_{T}$ (Xu, Zhang, Nagel, PRL 2005). Identify the gas-mediated force that lifts the thin liquid sheet ejected near the contact line, and derive $P_{T}$(V, R, liquid viscosity, gas mean free path) together with the time and position of sheet ejection.","problem_ref":"789c7d183315a46ee00f9052588cb93807a0eeb32e5195844c24759e22c7b05a","references":"","settled_by":"Simultaneous measurement of gas-film thickness, sheet ejection time and $P_{T}$ across gases and liquid viscosities, matched by a theory without fitted parameters.","status_note":"Competing models invoke aerodynamic lift on the advancing sheet (Riboux and Gordillo 2014) and Kelvin-Helmholtz instability of a thin air film (arXiv:1509.01230); none is confirmed over the full parameter range.","title":"How does the surrounding gas cause an impacting drop to splash?","topic_ref":null},"content_withheld":"false","files":[],"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"f099b6e830b808f5a33bf79c69aea85f4afc00cc279cb0c73164ba7a282a89d3","schema":"pubphys.attested/1"},"id_token":null,"id_token_withheld":"false","envelope":{"attested_hash":"fa7b27b158382f31038bde9af6d91fcfabde2dc5b8b0347d42b4fe393be052e2","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"PKUlbIi_lA0napBRaENOjh6GKoAhpJ8FDTlgrarwjLMHw57IN2Pn4MAxzo1-8I8vQDv1MzbJkrlxUz95vM8NCg"},"schema":"pubphys.envelope/1"},"ots":{"attested":["AE9wZW5UaW1lc3RhbXBzAABQcm9vZgC_ieLohOiSlAEI-nsnsVg4LzEDi96a9tkfz6veLcW4sDR9QrT-OTvgUuLwIPqdn5lxfOcQNelst6fcUrpuz_5L-hiy2NmwHdlLYAWRCPAgfAmCs4DKlN2wqieDchsZpUwP9QZaVRFvS-tNXo7k56II8SC_PkEwTObxbtuyOw-ZZnDs4z0fqz4IV4e_rkeQx-3aVwjxIEh0utbI2uYKIkzEPuJyUzv3vecxVe3Wy1tfaPt443FqCPAgyPoIxaouw9cYM_tJ1An7VaxGnbLBkR4O49bNEuCP05gI8SC-tKcgBscltf39qqvFXDW9FeXZ0N1z6gJlQnFYoXuTHQjwICHA10i6bPvZ9I1Ag67qE-LPAlaVdbccRYSx1XHhVLRDCPEgLknXQLPBphDVPQ2JIPapNIpNFDYAu57cOPZiO3xVZPcI8SBFZ7nkuh-5IaK75jNF2I3u9gWIJeTINL1f_rXWP5TwxwjxIK8CKI34eu_sgR6N3zB1SKGijO7ko6-mgEUnS-DdScYBCP_wCOf1iajMfCj1CPAQnjpoz1kO_dN22pXdltGw2AjxIE4XykgsZ_WSh2vkwqZCzoJ33eOitoafeDpQ-3_6R7A_CPAg4b6CYztt395HgCIMw1-W5LfG-vu-JwtH6wIGvmq0bZwI8CCtU0WsKh5BwLGGWacTQHMeBHwdClkCV-rMMMXN9ZvwZQjxBGrRZZPwCNknZwX9zuTwAIPf4w0u-QyOLCtodHRwczovL2JvYi5idGMuY2FsZW5kYXIub3BlbnRpbWVzdGFtcHMub3Jn8Aj1kxLXPF3sgQjwEN3TRaAlnRGdywLUXJqL_hoI8SC_EwWue7sXTkhbkg2KtpDc5URgyM3Hol8HHDVDiM8uLgjxBGrRZZLwCDbPE8C0jkmw_wCD3-MNLvkMji4taHR0cHM6Ly9hbGljZS5idGMuY2FsZW5kYXIub3BlbnRpbWVzdGFtcHMub3JnCPEgcCe_goUV_i6JgQUm8vGIzFLLPxWjAk_iuhN8MP2HtsgI8CCPm2C9s0XubFI_iMYYTrp7NQVEucjiDVVOS-5XhW0I8AjwILGVzUe4o5G4eCfsNghhwOFziij306RNYES910HKmhrsCPAgVyONoXyQM0NgJkZo0hKVGO9f4juKf5A3CyvglhBsUm8I8CCeXSTiCzsu5jmLW6aIc74nszLe4FOEslRZChj0t1VKtAjxIDr4W3XX8r8aow1ZiGRWxWoIW9dJhunhLwmguwsGdTO-CPEgELz-YATskE_flI3EMFwbuOgsnBRGkzF1Xa9I7rj-MQ4I8SB7TgKiPXFKLsITxTCqIEY2E_JnlB0P9hnCf6F5J05tTgjxIGB0NKCvdVTHWPyb-krv47MzDAWBd4vLje6N98K_6F_kCPAgyX4-cC3jGOgERVTj6eTI3Q0pFr0C9fiQQx-WUXIglL0I8VkBAAAAAfPitX67BAWDTZtWcQxQWCkh0YqMzi1a4gPWRNWeuOKwAAAAAAD-____AlREAgAAAAAAFgAUEXKzahzT5T5tisLdW6UYvM0Pl9sAAAAAAAAAACJqIPAEctMOAAgI8SAwkgFiLjrE4i4UPDMn2c7HXieBbkduCVR_rk5GmSghhwgI8CAeAZYQYIMdaCxzBP3Y06gnuz57Ns-TKJavZGdhkML93AgI8CC198zLIu74yxwmwNzR3PAaynBKuua9UCcw2CyBaEcKWAgI8CAxSXU58ENTCGnlVmMfBUDSe7PUXkdlNQkIcCczUvUXcwgI8CBK0rtRametS55XkRoTu4TTLoEsynoQA2atuGtOoQFm7wgI8CDktVbsge1QvmY068_HWE5N8syaqVDu30QVb4oO2shIhAgI8CAAGBdnq6kVTyqINAoW1AWmqSMrCXQ-zEzglSNUuUMpuQgI8CATBv3oWI6GOVvAjwYVlDhrkZfDGzhtR2pU4wqu0FZXfQgI8SCoGD7CnRzwIA9X2TonvAhr38a1B-laaGkTXOoVnKLalAgI8CDalktNU8YluuKLPRSEzK1gNVgBc6BCdYNysw57Ar07xwgI8SDGbdDDNu9PiyInO5tAadJPrtta_57FjBI8_UoOLsJpTAgI8SCbq51S51-NRozSBQVPKUoYMzKmPum0xMbTObF39PnJNwgI8CAyk4ieSMUJWnWk5mF9mfI8CXyF1YaYfNBysYuAvBIouAgIAAWIlg1z1xkBA_OmOw"],"envelope":["AE9wZW5UaW1lc3RhbXBzAABQcm9vZgC_ieLohOiSlAEISAVY7DIrIA096axKejKK_p5liTPExTuSvLkliFlreLDxIEfMC8VeMk86-SE97vGcboCnVpYPNkYNUG3IGDPdJZJ0CPAgURlZht0UUVn9XBVxZx8b78wPmo1uXbIjyAwVnm8erhkI8SCMqp8mzyAU6g6LG0XXT_DfuvXsMoCRr6VvzU35dF977AjwIElYbg2Wnzc1BIP5kmcyR9lCM1E0eufrTMPOZotUsOrDCPEgMX8oV34h_j_aI9XVqOqsHoldySGXyV3WuqszHJhVrpII8SCxSIzs5Bz2-aA0hohgWVe-Jl5Es-3tSXoAu69KEXg2YgjwIIty2HwK5vrs2CMdyGCJIg9c3gHEb2VgCePnDOqzEY_GCPEgY6scDRpMTELRyAdQzoM_M72JG6gtvT5rKuV0H9Htq4AI8SDYW1nvfhAbf15fxYweLGiGtYK21xyRv_zJHX5DdVcU4wjxIJdQdDsL3v2lA7qZb8kMJtOgaTQmbgchdPcS5lYJqDLnCPAgkPXX-naXR0fRIdS-sEDlzYmtMvSCNH42ESUF0QXb6NUI8CDQo_sIWZiWXaTGRSQBLmU-lHJKskYKqsjO1r02DhB8LAj_8Ajn9YmozHwo9QjwEJ46aM9ZDv3TdtqV3ZbRsNgI8SBOF8pILGf1kodr5MKmQs6Cd93joraGn3g6UPt_-kewPwjwIOG-gmM7bd_eR4AiDMNfluS3xvr7vicLR-sCBr5qtG2cCPAgrVNFrCoeQcCxhlmnE0BzHgR8HQpZAlfqzDDFzfWb8GUI8QRq0WWT8AjZJ2cF_c7k8ACD3-MNLvkMjiwraHR0cHM6Ly9ib2IuYnRjLmNhbGVuZGFyLm9wZW50aW1lc3RhbXBzLm9yZ_AI9ZMS1zxd7IEI8BDd00WgJZ0RncsC1Fyai_4aCPEgvxMFrnu7F05IW5INiraQ3OVEYMjNx6JfBxw1Q4jPLi4I8QRq0WWS8Ag2zxPAtI5JsP8Ag9_jDS75DI4uLWh0dHBzOi8vYWxpY2UuYnRjLmNhbGVuZGFyLm9wZW50aW1lc3RhbXBzLm9yZwjxIHAnv4KFFf4uiYEFJvLxiMxSyz8VowJP4roTfDD9h7bICPAgj5tgvbNF7mxSP4jGGE66ezUFRLnI4g1VTkvuV4VtCPAI8CCxlc1HuKORuHgn7DYIYcDhc4oo99OkTWBEvddBypoa7AjwIFcjjaF8kDNDYCZGaNISlRjvX-I7in-QNwsr4JYQbFJvCPAgnl0k4gs7LuY5i1umiHO-J7My3uBThLJUWQoY9LdVSrQI8SA6-Ft11_K_GqMNWYhkVsVqCFvXSYbp4S8JoLsLBnUzvgjxIBC8_mAE7JBP35SNxDBcG7joLJwURpMxdV2vSO64_jEOCPEge04Coj1xSi7CE8UwqiBGNhPyZ5QdD_YZwn-heSdObU4I8SBgdDSgr3VUx1j8m_pK7-OzMwwFgXeLy43ujffCv-hf5AjwIMl-PnAt4xjoBEVU4-nkyN0NKRa9AvX4kEMfllFyIJS9CPFZAQAAAAHz4rV-uwQFg02bVnEMUFgpIdGKjM4tWuID1kTVnrjisAAAAAAA_v___wJURAIAAAAAABYAFBFys2oc0-U-bYrC3VulGLzND5fbAAAAAAAAAAAiaiDwBHLTDgAICPEgMJIBYi46xOIuFDwzJ9nOx14ngW5HbglUf65ORpkoIYcICPAgHgGWEGCDHWgscwT92NOoJ7s-ezbPkyiWr2RnYZDC_dwICPAgtffMyyLu-MscJsDc0dzwGspwSrrmvVAnMNgsgWhHClgICPAgMUl1OfBDUwhp5VZjHwVA0nuz1F5HZTUJCHAnM1L1F3MICPAgStK7UWpnrUueV5EaE7uE0y6BLMp6EANmrbhrTqEBZu8ICPAg5LVW7IHtUL5mNOvPx1hOTfLMmqlQ7t9EFW-KDtrISIQICPAgABgXZ6upFU8qiDQKFtQFpqkjKwl0PsxM4JUjVLlDKbkICPAgEwb96FiOhjlbwI8GFZQ4a5GXwxs4bUdqVOMKrtBWV30ICPEgqBg-wp0c8CAPV9k6J7wIa9_GtQfpWmhpE1zqFZyi2pQICPAg2pZLTVPGJbriiz0UhMytYDVYAXOgQnWDcrMOewK9O8cICPEgxm3QwzbvT4siJzubQGnST67bWv-exYwSPP1KDi7CaUwICPEgm6udUudfjUaM0gUFTylKGDMypj7ptMTG0zmxd_T5yTcICPAgMpOInkjFCVp1pOZhfZnyPAl8hdWGmHzQcrGLgLwSKLgICAAFiJYNc9cZAQPzpjs"]},"log":{"leaf_index":"3260","tree_size":"3804","proof":["e2b12d73b25b7cee9cb62aa3d6927c23db5835ff6455106eb77dd5e6ae4357be","30517787b4d759bcae4ff9c4dbb0dc6850268b0b27f747dc2450a91ecc40643e","37b8d27bc6e66946dc4cb74f47bf2f2cfb68e4b8f886ddc13878638beee1b400","9b8ada902a979e5cf3c7fbf8be7f2e62e2015fd7ba862796a20c19d7d683375b","0474a467c9ee8e75e01e4804ccd534fa307ed958ff5de0b0d3c136242a7f178d","51747b36322b0d617609b618a645021cf4cc14a8f75b6309c7b53c622df86ebc","bcad5f24fa771bddd97e4cf7acbfd5d77087bad3e6f94962b11c748e4aeb9cd0","1ed62395399131ae4d5b365e81f741fbe796392ae81801387a716b09dc35a694","48906313613fdfddd2bd907650210a7f3e59ccb380a2b862e892089f41bcdced","98b5a14b42b3a202b6ef825f66833fa505601404c4c0f14575f3ec922607a858","af34d80d0065c0ab502282775e865492e2cb49c9493f4594d63ba5577922854a","3c578dccc15502c5f3efe228cadc99fee76ab536ed01f66b14d316fdcc157429"],"checkpoint":"pubphys.com/log/v1\n3804\nAK6t4qgu96+M9wScTrIlsJ10d/zhKVEtYguyM3aeJvo=\n\n— pubphys.com/log/v1 JFPwIPP8EtoxgcsQg7V7CwIdL4UKPqJtpv+eB8sFNJjyQHIdyA1VabmBsPyLqq2bLxJPn57rA6fQi8y0QDDjRXHvlQg=\n","promise":"pubphys.com/log/v1 promise\ne7302d3c8eed099e2cd8f2984c4bc47a8fccb224ddc8a68e97835e5fa814ddc3\n3260\n2026-10-15T23:43:57Z\n2026-10-16T01:43:57Z\n\n— pubphys.com/log/v1 JFPwICppn+oMe7QcMi2zl3q/p7tsVXOAas9TWECDAj3Q6x/pQexoxRgthOP7Uidw6DdYZ0W+knhF56tBfBYUU1ptaw0=\n"},"orcid_key_evidence":[],"attesting":null}