Why do things fall? How to explain why gravity is not a force

Stannard, Warren

doi:10.1088/1361-6552/aa9d6e

Cited by 7 publications

(7 citation statements)

References 7 publications

(10 reference statements)

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“…Because gravity is an acceleration, not a force, it depends on the mass of the whole organism to create the mechanical stimulation of cells on Earth that is then diminished during spaceflight 51 . Although various simulation devices have been developed and optimized, it remains difficult to realistically simulate the microgravity environment on the ground.…”

Section: Discussionmentioning

confidence: 99%

Simulated microgravity reduces quality of ovarian follicles and oocytes by disrupting communications of follicle cells

et al. 2023

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Ovarian follicles are the fundamental structures that support oocyte development, and communications between oocytes and follicle somatic cells are crucial for oogenesis. However, it is unknown that whether exposure to microgravity influences cellular communications and ovarian follicle development, which might be harmful for female fertility. By 3D culturing of ovarian follicles under simulated microgravity (SMG) conditions in a rotating cell culture system, we found that SMG treatment did not affect the survival or general growth of follicles but decreased the quality of cultured follicles released oocytes. Ultrastructure detections by high-resolution imaging showed that the development of cellular communicating structures, including granulosa cell transzonal projections and oocyte microvilli, were markedly disrupted. These abnormalities caused chaotic polarity of granulosa cells (GCs) and a decrease in oocyte-secreted factors, such as Growth Differentiation Factor 9 (GDF9), which led to decreased quality of oocytes in these follicles. Therefore, the quality of oocytes was dramatically improved by the supplementations of GDF9 and NADPH-oxidase inhibitor apocynin. Together, our results suggest that exposure to simulated microgravity impairs the ultrastructure of ovarian follicles. Such impairment may affect female fertility in space environment.

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Section: Discussionmentioning

confidence: 99%

Simulated microgravity reduces quality of ovarian follicles and oocytes by disrupting communications of follicle cells

et al. 2023

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“…Second, the curvature of the timeaxis is chosen in such a way as to make a freefall tra jectory in the heighttime diagram straight. Thus, the timeaxis curves somewhat arbitrarily and the curvature does not accurately correspond to the way spacetime is warped around the Earth 3 .…”

Section: Warped-time Modelmentioning

confidence: 99%

“…The first direct detection of gravitational waves in 2015 [1] has led to a new interest in topics of gravity and gravitational astronomy. This interest leads to new opportuni ties for teachers and educators to engage students and the general public [2][3][4]. Indeed, topics of GR and astronomy seem to motivate high school stu dents to a great extent [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Free fall in curved spacetime—how to visualise gravity in general relativity

Kersting

2019

Phys. Educ.

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The first direct observation of gravitational waves in 2015 has led to an increased public interest in topics of general relativity (GR) and astronomy. Physics teachers and educators respond to this interest by introducing modern ideas of gravity and spacetime to high school students. Doing so, they face the challenge of finding suitable models that visualise gravity as the geometry of curved spacetime. Most models of GR, such as the popular rubber sheet model, only address spatial curvature. Yet, according to Albert Einstein, gravitational phenomena stem from deformations both in space and time. This paper presents a new model that builds on a relativistic generalisation of Newton's first law. We use Einstein's free fall thought experiment and a classical heighttime diagram to explain how warped time gives rise to gravity. Our warpedtime model acts as a convenient supplement to the rubber sheet model. To support teachers in integrating the model into their classroom practice, we have implemented the model as an interactive simulation that is freely accessible. The model is the result of a threeyear period of developing and trialling digital learning resources in Norwegian high schools. Based on these trials, we suggest specific instructional strategies on how to use the warpedtime model successfully in science classrooms.

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“…While in recent years physicists and science educators have argued for introducing general relativity to undergraduate and high school curricula, initial efforts to do so have mostly focused on the development of teaching approaches rather than to look at students' experiences and learning processes (eg. Kaur, Blair, Moschilla, Stannard, & Zadnik, 2017;Kersting, Henriksen, Bøe, & Angell, 2018;Stannard, 2018;Velentzas & Halkia, 2013). Consequently, student meaning making processes, including the role of imagination and its emergence, have been largely overlooked.…”

Section: General Relativity As Imaginative Challengementioning

confidence: 99%

Metaimagining and Embodied Conceptions of Spacetime

Steier

Kersting

2019

Cognition and Instruction

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Though we live in a four-dimensional universe, our minds and bodies are not particularly good at perceiving and depicting four dimensions. This study contributes to our understanding of collaboration with abstract concepts by examining particular activities where bodily and experiential understandings may conflict with the conceptual domain. Specifically, upper secondary physics classrooms studying Einstein's general theory of relativity are taken as a setting to identify the representational practices and conceptual challenges that arise when learners attempt to make meaning with, and express conflicting notions of, space and time. To unpack these challenges, we draw on the concept of imagination and on theoretical perspectives that treat imagining as a social activity. We also present the concept of metaimagining to characterize layered processes in which learners attend to and manage shifts between their own imaginative activities. This concept is illustrated through a detailed analysis of an extended conversation between two upper secondary physics students working with general relativity and spacetime. The students perform a diverse set of imaginative activities that are strongly tied to communicative, cognitive, and bodily action. We also show how the unique domain of general relativity presents particular challenges to student meaning making of abstract concepts which in turn prompt metaimagining. Based on our analysis, we offer recommendations to improve instructional practices in general relativity and argue for the consideration of imagining as a transdisciplinary competency in math and science education.

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Why do things fall? How to explain why gravity is not a force

Cited by 7 publications

References 7 publications

Simulated microgravity reduces quality of ovarian follicles and oocytes by disrupting communications of follicle cells

Simulated microgravity reduces quality of ovarian follicles and oocytes by disrupting communications of follicle cells

Free fall in curved spacetime—how to visualise gravity in general relativity

Metaimagining and Embodied Conceptions of Spacetime

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