There are a few types of day traders out there. There are those that like to use charts to enter and exit trades and then there are those that like to watch the price directly and place trades using the time and sales information. These days most traders like to use charts as the modern computer has no problems showing many charts along with time and sales information. By far the most popular chart for day traders is the five minute chart.
Most traders use candlesticks as the price display on their charts. The reason for this is that a candlestick gives the most detailed information in the most condensed format. For this reason it is the most popular price display format on a chart. So why is the five minute time period the most popular? Well its likely that it is the most comfortable. See as traders get better they can learn how 1 minute and 2 minute charts may allow for faster entries, but in the beginning the 5 minute chart seems to have the best pace.
In reality it doesn't matter which chart you use. A 1 minute chart is just a slice of a 5 minute and a 2 minute is just a multiple of the 1 minute chart. Many new traders are taught to find patterns. When learning those patterns it can be stressful to try and find one as each one minute candlestick passes so 5 minute is usually the go to time period for many educational firms.
The reality is that patterns are a great tool for teaching how to see the emotion of other traders inside of a chart, and using a 5 minute chart is by far the best to teach on. As one gets better and more comfortable though they begin to realize that any time period will do and its how the price moves that will ultimately generate your entries and exits.