[fwd.] The Four Sentences of Hengqu

An attempt at a translation of my motto, which was written about ten centuries ago. 为天地立心,为生民立命,为往圣继绝学,为万世开太平。张载(1020 - 1077) This motto has been used in diplomatic situations for several times in history, and translations, some with explanations, are readily available. Still, I will try to give it my own translation below. To decree the principles of … Continue reading [fwd.] The Four Sentences of Hengqu

[Little Demos] 04 – What Curve Do Shadows Trace (On a Spherical Earth)?

This was a cancelled "Work-At-Home" experiment for physics undergraduates, due to local weather conditions, and a second thought that this project is better suited for high school students. Conic Sections You may skip to the next section if you are comfortable with analytic geometry or related mathematical fields. If you use a plane to cut … Continue reading [Little Demos] 04 – What Curve Do Shadows Trace (On a Spherical Earth)?