The components were attached in a circuit as shown in the circuit diagram below;
The DC power supply was set to the lowest setting (2 V).
The power was switched ON and careful observations on the appearance of the globe were made.
What do you think will change in the appearance of the globe as the voltage is increased?
Will it be easier and safer to look at light given off or to assess heat given out by the globe?
If you measure light will your measurements be qualitative or quantitative?
The result was recorded in a table. Design your table so it communicates to others your observations in a clear manner. Plan your investigation making a risk assessment before you actually begin.
This was repeated, in turn, for each higher setting on the DC power supply, i.e. 4, 6, 8, 10 and 12 V or 1.5, 3, 4.5, 6, 7.5, 9, 10.5 and 12 V. The results were recorded, analysed and a conclusion written.
This was repeated, in turn, for each higher setting on the DC power supply, i.e. 4, 6, 8, 10 and 12 V or 1.5, 3, 4.5, 6, 7.5, 9, 10.5 and 12 V. The results were recorded, analysed and a conclusion written. The nail and the copper strip were polished with some sandpaper and then inserted into small slits in the surface of the lemon, being sure that they did NOT come into contact (as shown below).
An electrical lead was attached to the nail and another to the copper strip.
The other end of the leads were then touched briefly to a galvanometer and the result observed.
The wires were then reversed on the galvanometer and again touched to the contacts. The result were recorded.
The results were then analysed and a conclusion written.