The price movements of any stock are posted throughout the trading day and summarized at the end of the trading day. For example, April 2, 2019, shares of Apple Inc. (AAPL) opened at $191.09 and closed at $194.02. During the day, as indicated in the "day's range" listed to the right of the closing price, shares dropped as low as $191.05—the intraday low—and hit a peak of $194.46—the intraday high.
Due to the increased leverage and quick returns, day trading can be extremely profitable. The downside is that if done incorrectly, it can also be extremely unprofitable. Due to the high volatility of day trading, some people have labeled Day Traders as gamblers or adrenaline junkies. However, many people make a very consistent and comfortable living from day trading. Some even make millions of dollars each year.
Relative Strength Index (RSI) – Used to compare gains and losses over a specific period, it will measure the speed and change of the price movements of a security. In other words, it gives an evaluation of the strength of a security’s recent price performance. Day trading tip – this index will help you identify oversold and overbought conditions in the trading of an asset, enabling you to steer clear of potential pitfalls.
Sincere interviewed professional day trader John Kurisko, Sincere states, Kurisko believes that some of the reversals can be blamed on traders using high-speed computers with black-box algorithms scalping for pennies. “That’s one of the reasons many traders get frustrated with the market. The timing is not like it used to be, and many of the old rules don’t work like before.” 
Day trading was once an activity that was exclusive to financial firms and professional speculators. Many day traders are bank or investment firm employees working as specialists in equity investment and fund management. Day trading gained popularity after the deregulation of commissions in the United States in 1975, the advent of electronic trading platforms in the 1990s, and with the stock price volatility during the dot-com bubble.