Updated: Jun 3, 2020
I had a great discussion today with a student about prepositions. I also had a moment of inspiration when talking about the difference between across and through, as they are similar.
Across vs Through
First, let's clarify the definitions of across and through. Across means to go from one side to the other. You can also be sitting on the other side (across from) or be located on the other side of the street (across the street). Through means to go from one side to the other, also. However, it implies that you are also surrounded by something, while doing so.
The story of the needle as it passes through material
Imagine someone sewing by hand. They have a needle with a piece of thread attached and a piece, or pieces, of material being stitched. First the person ties a knot at the end of the thread. Then the person points the needle down and goes through the material with the needle ending up on the other side of the material. Next, the person moves the needle to the other side by going up and across the material (or over), but not through! Only once the needle has moved across the material to the other side, does the needle go through the material again, to continue sewing.
I hope this helps you visualize the difference between across and through!