- Cold Cathode Crookes Tube with cross plate
The purpose of Narika Crookes tubes in the demonstration
Narika Crookes tubes have two purposes in the demonstration. The 1st one is to confirm the electron have a negative charge. And the 2nd one is to confirm the electron have behavior of particles.
1. Confirmation or demonstration that the electron has a negative charge (with deflection plate inside).
Deflection plates are assembled at near by negative electrode, each plate is located upper and lower side of beam way inside of tube. In a dark room or box, the demonstration is showed the behavior of electron beam depend on the charging deflection plates such as voltage or polarity.
In the first demonstration, you observe the way of electron beam without any charges to deflection plate. In this observation, you can understand the electron beam is emitted linearly from negative electrode to positive electrode inside.
In the 2nd step demonstration, during emitting the electron beam linearly, you charge the deflection each plate to positive or negative. Then the linear electron beam is changed a curving line by the deflection plate. Depend on a level of its voltage or turning over polarity, you can control the curving line of electron beam.
Through those observation of the electron behavior, you can explain that electron have a negative charge to students.
2. Confirmation or Demonstration of the electron’s behavior of particles.
The metal cross plate as a positive pole is assembled movable plate like a tip-up one inside. And the inside surface of tube end at back side of the metal cross plate is coated by fluorescence agent. Then when the emitted electron from the negative pole reaches at its inside surface of tube, the fluorescence agent on it becomes green luminous.
When the part of emitted electron is trapped by the metal stands and the other part of emitted electron reaches the end of tube, a shadow of cross is projected onto the end of tube. Therefore the electron has particles behavior.
Capability of Crookes tube (with deflection plate, cross plate)
Narika Crookes tube has a good enough capability to accomplish those two purpose in the demonstration. However, the caused Crookes tube is made by hands
When Electron Beam is emitted from anode side and collides with cathode of cross plate, shadow of cross plate appears on surface of glass tube inside. The operating voltage of tube does not require high voltage by an induction coil, it is just less than 5,000V by 4 batteries (AA) or AC Adaptor DC6V.
- Operating Voltage: less than 5,000V
- Power: AC adaptor or 4 Alkari Batteries (AA)
- Size: 260×160×215mm
- Weight: 1.3kg
Experiments in progress