P1.1.3.2 Determining the Gravitational Constant (IRPD)

Determining the Gravitational Constant (IRPD) Determining the gravitational constant with the gravitational torsion balance after Cavendish recording the deflections and evaluating the measurement with the IR position detector and PC. This apparatus can be ordered as a complete set or individually for use with equipment your laboratory may already have. To select products for this experiment separately, use the item numbers listed at the bottom of this description to search and add to your cart. The IR position detector (IRPD) enables automatic measurement of the motion of the lead balls in the gravitation torsion balance.  The four IR diodes of the IRPD emit an infrared beam; the concave mirror on the torsion pendulum of the balance reflects this beam onto a row of 32 adjacent phototransistors. A microcontroller switches the four IR diodes on in sequence and then determines which phototransistor is illuminated each time. The primary S range of illumination is determined from the indiv