They should identify the confounding variable.
Some condition that is not examined by the scientist might alter the experiment result. That condition is called confounding variable. If the method of the experiment same but result is very different, there should be unidentified confounding variable. It could be air humidity, temperature, ventilation, light, time of the year or anything that might not be seen by naked eye.
Try to redo the experiment with controlling variable as much as possible.
It is an open series circuit and this is why:
its obvious its a series circuit because all the symbols are in a straight rectangle.
its an open circuit because an open circuit has something that doesn't allow the electrons to flow all the way. and the thing blocking the electrons it the switch which is open, (off).
Hope this helped!! sorry its late!!
Answer:
the electron cloud model is the current model of atom
