It wasn’t your ordinary science class. It wasn’t your ordinary history class. It was science history, the science of electricity that is.

Elementary school students from two different schools lit up with excitement Tuesday when they learned about the early days of electric power generation at the Pennsbury hydroelectric mill.

The hydroelectric mill on Fairville Road was built in 1917 and it supplied power to the Danby residence until 1935.

Matt Ochs, of the Pennsbury Historic Commission, demonstrated mill operations to a group from West Chester Friends School during the afternoon. Students from Pocopson Elementary School went through in the morning.

He said the little power station was likely used to light the home — eliminating the need for kerosene lamps — and to drive a well pump for indoor plumbing throughout the house.

The kids described the mill as awesome and cool and thought it was neat that if you made the wheel go fast, lights would come on.

As one student understood it, the mill was needed before there was a modern electric grid because “There were no tall thingies that carry wires.”

The “tall thingies” are utility poles.

Ochs explained how the mill needs running stream water to run the wheels that crank out the energy.

In the early days, he said, private hydroelectric mills were the only way to have electricity in rural areas.

He explained how electricity was generated and how volts and amps create watts.

At slow speed, the Pennsbury mill supplied 10 watts of power by generating five volts at two amps. But when the mill wheels sped up — by pulling ropes to allow greater water flow — there were 60 volts at seven amps generating 420 watts. At that rate, lights in the mill house lit up. (See top photo.)

At other stations at the mill, students learned about solar and steam power as part of their science curriculum.