They are actually very different.
When you invest you are generally investing for a reason, you may like the companies' fundamentals, you may like the technology, the management, there could be a multitude of reasons which you want to invest in the company.
When you are looking to trade, you have an idea of what you are going for.
You can make a certain percent on the move, you generally set a stop and a target.
You have a defined time period, whether it is 5 minutes, the end of the day, a month, etc.
There are many different types of trading that one can do, fundamental, swing, position, pairs, etc.
When trading penny stocks you generally look at it a bit differently.
You will not ask yourself, "how will this company do in 10 years?", instead you will most likely say something like "this company is breaking out, what's going on?", you then look up the news and find out whether it's something which you would like to get into or not.
You make your move, or you get stopped out, and then you continue.
You do not hold it hoping that it turns into the next Microsoft, which it may very well do.
Penny Stocks can work well both as an investor, or as a trader.
One is certainly not better than the other, investing is longer term, without a finite life, your risk is usually higher, but you will be able to make it big.
When you trade, you will make a large percentage much faster, but you will usually never be able to catch the stock that most people only dream of, which is actually fine for me.
I do not need 100000% my return, a much lower percentage will make me a very happy man.