World pendulum - a distributed remotely controlled laboratory (RCL) to measure the Earth's gravitational acceleration depending on geographical latitude

摘要

We suggest that different string pendulums are positioned at different locations on Earth and measure at each place the gravitational acceleration ( accuracy Delta g similar to 0.01 m s(-2)). Each pendulum can be remotely controlled via the internet by a computer located somewhere on Earth. The theoretical part describes the physical origin of this phenomenon g(phi), that the Earth's effective gravitational acceleration g depends on the angle of latitude.. Then, we present all necessary formula to deduce g(phi) from oscillations of a string pendulum. The technical part explains tips and tricks to realize such an apparatus to measure all necessary values with sufficient accuracy. In addition, we justify the precise dimensions of a physical pendulum such that the formula for a mathematical pendulum is applicable to determine g(phi) without introducing errors. To conclude, we describe the internet version - the string pendulum as a remotely controlled laboratory. The teaching relevance and educational value will be discussed in detail at the end of this paper including global experimenting, using the internet and communication techniques in teaching and new ways of teaching and learning methods.