Differences between words that tell time: 时间 vs. 时候, and 点 vs. 小时
时间 and 时候 are both related to time, but their usage is a bit different.

时间 means the "physical time". For example 你在什么时间睡觉？ What time do you sleep?

时候 means "when". For example: 你什么时候睡觉？ When do you sleep?

点 and 小时 are used differently. 
小时 is used when you actually calculate the time taken in terms of hour. For example, 我睡了一个小时。I slept for 1 hour.

点 is used to ask the precise time at the moment. For example, 现在几点了？ What time is it now?

In English, you don't ask "What hour is now", instead, you ask "What time is now". In mandarin, it's also the same. You don't ask "现在几小时了", instead you ask "现在几点了".

Hope this help :)