Kindergarteners, elementary schoolers, and even high schoolers are unlikely to remember the physics behind the new permanent exhibition demonstrating “horsepower” at Jerusalem’s Bloomfield Science Museum.
But they will recall their turning of wheels to get things moving, create light and magnetic fields, make objects jump, and even produce hydrogen to make a miniature rocket pop noisily at the top of a column. Something will stick in their minds about what they saw when (or if) they take a physics class in the highest grades.
The museum’s creative minds conceived and built the exhibits that make up the “Horsepower” exhibition on the top floor. Although there were no horses, there certainly was a lot of power. At the opening last Friday, some of those who built the exhibits stood by to adjust small parts to make sure they were working as planned despite constant use by the children (and adults).
Bloomfield’s trained Jewish and Arab guides explained how a pendulum works, and the young participants in the library were even given parts to make their own and create colors that appeared and then disappeared on a piece of paper. The children were also shown how to make a miniature helicopter with a stick and rubber bands, inspired by Leonardo da Vinci, which flew upward and that they took home.
Many of the gadgets on display were explained by signs on the wall in Hebrew, English, and Arabic for all to see and consult.
The arm of a motor raises a pendulum to a certain height (giving it potential energy); when the pendulum is released, this energy is converted into kinetic energy (movement). In an ideal world without friction, the pendulum would continue to swing like this forever. The magnets moving across the coil generate an electrical voltage. When the LEDs were connected to the coil, they “pulled” the kinetic energy of the pendulum to create light, slowing it down as a result.
The participants then saw how the speed of the magnets affects the intensity of the light. When they pushed a green button to activate a motor that released the pendulum, they observed it swinging and the magnets moving back and forth across the coil.
Aiming to increase awareness of energy
RON EIFER, director of the Sustainable Energy Division at the Ministry of Energy and Infrastructure that sponsored the exhibition, said at the opening: “We believe that education is the basis for significant change in the energy sector; therefore, our ministry is investing significant resources for this. Through this new exhibition, we aim to increase awareness about the energy issue and the challenges in the field and to transform hundreds of thousands of children each year into agents of change on the path to making the Israeli energy sector more efficient, advanced, and cleaner.”
Electric cars are quiet, reliable, and don’t pollute the environment – but unlike vehicles that run on gasoline, electric ones need to be charged with electricity that is largely generated from burning fuels in power plants. In many cases, the pollution emitted by burning the fuel exceeds the pollution that would have been emitted by the internal combustion engine of a similarly sized gas-fueled car.
There are miniature turbines connected to an electric generator that converts wind energy into electrical energy that powers light bulbs. Wind energy was used in the past to sailboats, grind flour, and dry food. Turbines allow wind to be converted into electrical energy that can be transferred or stored.
Although wind is free, large turbines are relatively expensive and can be installed only in wide-open places where there are strong winds. Scientists and engineers are working to develop smaller turbines that are suitable for weak winds and can be installed in neighborhoods and even on private roofs, similar to solar cells.
In some devices, heating causes energy loss, so developers try to minimize it. This is the principle and the limitation of transformers that operate only with alternating current (AC); however, when the current is direct (DC), the bulb will not turn on. Their use is also the reason that almost all electricity grids operate on AC rather than DC.
Light bulbs are examples of technological developments designed to meet a basic need that has not changed over the years. Bonfires were replaced with oil lanterns, candles, and gas lamps, which were polluting and dangerous. In the 19th century, we switched to electricity and incandescent bulbs, and in the 20th century to LEDs.
Incandescent bulbs convert electricity into heat that ignites a metal wire that emits light; they are hardly used anymore. About 10% of the energy is converted into visible light, with most “wasted” as heat. In LED bulbs, light is produced almost directly by the movement of electrons jumping from one energy level to another in a process of ionization and excitation.
But who knows what will replace LEDs by being more efficient and what exciting horsepower energy sources are in our future? Hopefully, some of the children who visit “Horsepower” will help make them happen.