_:nfc7c648d4803444fa66d50700b102fa5xb25
<http://schema.org/reviewBody>
"This becomes a stimulating demonstration for advanced students beginning to understand quantum physics.  If the ends are touched lightly, the red lights....better contact causes the green and blue to light subsequently.  They then figure out that blue is highest frequency and requires more energy and higher voltage.  There&#039;s a lot in this lesson!"
<https://www.teachersource.com/product/energy-tube/>