4.6
Ions on the hike Experiment (Photo
1)
1.
Cut a stripe of filter paper as broad as of the slide and 2 cm longer.
2. Fold the stripe around the slide. Fix it on the lower side.
3. Prepare two pencil leads that are 1 cm longer than the slide´s breadth.
4. Fix them at the sides with paper clips
- like seen in photo
2.
. . These electrodes must have a free end to fix
the corocodile clips.
.......................
5. Completely wet the paper and the electrodes with sodium sulfate solution.
6. Connect the 6 batteries in series - like seen in Photo
2 -. Press 10 of the 12
terminals together like popers.
7. Connect the black wire with the negative terminal and the red one with the
positive terminal.
8. Soak cochenille read into the thread. Place it on the middle of the wetted
paper parallel to the electrodes.
9. Repeat 1 - 9 with methylene blue.
Observations Photo
2: The cochenille red ions migrate
to the positive electrode (anode). Photo
3: The methylene blue ions migrate
to the negative electrode (cathode).
Explanation
The
colour of the food dye cochenille
red A is
generated by its negative ions (= anions), the colour
of methylene
blue by its
positive ions (= cations).
The positive electrode (anode) attracts negative ions (anions). The negative electrode
(cathode) attracts positive ions (cations).back.....................,,........first
publication: 08.06.2010............last
modification: 08.06.2010
