Electrolysis with baking soda solution, a penny as the cathode and graphite for the anode I set up an electrolysis experiment to show my kids and wanted to explain to them what is happening.
My setup has a penny as the anode and graphite for the cathode. The solution is water with baking soda mixed in.
I see bubbles at each of the electrodes which I assume are hydrogen and oxygen bubbling out. I also see some cloudy substance coming off the penny, which I assume is some sort of copper compound, but I'm not sure.
Can someone help me figure out what's going on in the setup at the two electrodes?
Edit : corrected the electrode descriptions. I earlier stated penny as the cathode and graphite as the anode.
Yes, I agree you are getting hydrogen an oxygen as you expected.
However, the copper anode is undergoing anodic corrosion and forming CuO (which is characteristically black) and possibly also some Cu2O (yellow or red, depending on the size of the particles, where the color combination could be described as orange).
Now, in the presence of HCO3- and O2, a naturally occurring mixed salt, copper patina (which forms on the copper roofs of houses) could also be forming. Wikipedia on patina, to quote:

patina is a coating of various chemical compounds such as oxides, carbonates,... formed on the surface during exposure to atmospheric elements (oxygen, rain, acid rain, carbon dioxide,...

Patina has been described as a blueish-greenish naturally forming on a copper surface (here, your copper penny electrode).
A closely related version of your electrolysis experiment has been previously discussed elsewhere.