Introductions and abstracts are two things that seem very similar, but are actually quite different. However, once you know the difference, they are easy to keep separate from each other.
An abstract is, at its most basic level, a summary. It outlines all of the important parts of your paper to the reader, so they can figure out if your paper is worth reading. This is why abstracts are important in the scientific field. They are a fast way for someone to analyze what is going to be said, and if that information is going to be beneficial for them.
An introduction provides the reader with detailed background information about a topic. This helps the reader make sense of what is going to be said later in the paper. If they do not understand the most basic parts of your topic, then they are not going to understand what you are trying to convey.
Now that you know the difference between the two, here is some advice for writing them:
The abstract is easiest to write last. By that point, you will have already written everything else, and you should know the important takeaways of your work. In the abstract, you should introduce your topic, discuss why you choose this topic, state your hypothesis, and reveal the results of your study. Remember, the abstract is like a summary. You should not go into a lot of detail here. Provide the reader with enough information that they can digest what you are saying. You will explain everything else in detail later in your paper.
The introduction is one of the most important parts of your paper. However, introductions vary based on the genre of paper. For this blog post, introductions for scientific papers are going to be discussed because abstracts are a staple of scientific reports. An introduction for a scientific paper should explain the reasoning behind why you choose this experiment, provide background information about the topic, reference other studies done on similar topics, and state your hypothesis. You want to make sure your reader can understand what is going to be said later in the paper.
Here are a few websites that have some more information about the two: