What tool, associated with homo erectus, is perhaps the most successful tool humans ever invented?

For the answer to the question above, the most successful tool they invented was hand axes made with sharpened stones and wood. They can hunt and chop animals in the wild. They can also use it for chopping trees. I hope this helps

You should never redesign your experiment. try and see what in your experiment you made a mistake on or try and test your experimemt with somebody else. see if they get the right results.