The two polarizer setup filters vertically and horizontally, so no light gets through. By adding a third one one in between, a superposition of vertical and horizontal polarization is induced in the light from the first polarizer, thus some light can pass through the third one. Also known as the Dirac three polarizer experiment
This demonstration demonstrates the Thermo-Electric effect and the conversion from heat energy into electrical energy and then into mechanical energy. It also demonstrates “useful energy”: the total heat energy is approximately the same in both scenarios, but only in the first one can we actually extract work from it
This demonstration shows energy conversion from heat to electrical in the Carnot cycle. Through varying the flame intensity, it can show that the work done by the system varies with the temperature difference and thus the heat input. Through the generator, it also shows that useful work can be extracted from the system.
This demonstration illustrates conservation of energy. The launcher stores potential energy, which is then converted to kinetic energy via the ball. The ball transfers this energy to the pendulum. By measuring the height reached by the pendulum, the potential energy can be calculated.
This demonstration illustrates how the ball has no “memory” of its initial direction of travel. We see the movement of the ball as it leaves the roller is perpendicular to the initial direction of travel.
The experiment shows how 2 oscillators with slightly different frequencies will drift in and out of phase in a process called “beating”. The frequency of this beating is the difference between the frequencies of the 2 oscillators. If the difference is very large, a “difference tone” might be observed, where the beating becomes fast enough to be heard as a 3rd tone, but this experiment is not able to create such a tone.
This demonstration shows how the forces are balanced, as the Newton meter should stay stationary as the masses are increased, and should show the sum of the forces created by the masses, demonstrating the tension in the string.
This demonstration shows Gyroscopic precession, which is a phenomenon that arises when a torque is applied to a spinning wheel (in an axis other than the one the wheel is spinning around). Because not all parts of the wheel are equidistant to the axis of the torque, the coriolis effect causes a torque in the 3rd axis, inducing a rotation. This rotation then induces a counter-torque in the original axis, keeping the wheel horizontal. This also explains why the wheel drops down once the precession is stopped.
This demonstration shows the conservation of angular momentum, since the excess of momentum created by “reversing” the rotation of the wheel is transferred to the person on the stool.
Although the force generated by the fan is constant, the track and wheels restrict the movement, and thus the component of force in the direction of movement is proportional to the sine of the angle.