Many things happen duing a "Gizmo". Graphs and charts are created for analysis (even though this blog won't let me paste one in to show you). This helps the kids see the data that is generated during their experiment in an organized fashion in order to help them to analyze their results. They can then use this information to form a conclusion to their hypothesis and answer the Critical thinking and extended thinking questions that are part of their lab.
There are Gizmo's for many different levels. In my co-taught class, we can be using 2-3 different Gizmos for the different level students, but the all address the same standard.
Here is a good video that goes more in depth: