Two atoms bump into each other. One says 'I think I lost an electron!' The other asks, 'Are you sure?', to which the first replies, 'I'm positive.'
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so, I am a nerd. This is my favorite science joke. Of course, most will not think it is funny and most science jokes may be considered more pure puns, rather than jokes.
In a similar vein, most "x walked into a bar jokes" are not based on a wrongness, I think. But, again they are more word play than actual jokes. No belly laughs for them?
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A termite walks into a barroom and asks, "Is the bartender here?"
A neutron walks into a bar; he asks the bartender, 'How much for a beer?' The bartender looks at him, and says 'For you, no charge.'
A man walks into a bar with a slab of asphalt under his arm and says, "A beer please, and one for the road."
A guy walks into a bar with jumper cables. The bartender says, "You can come in, but don't start anything!"
etc.