My first year of teaching middle school science there were several topics I came across in the standards that I don’t ever remember having been taught myself. Being the ever-diligent lifelong learner that I am, I began to study each topic. One of these topics was Topographic Maps. How had I gotten all the way through college and NEVER heard of the term Topographic Map?! (In all fairness, I grew up at sea level my entire life- so elevation wasn't really something we talked about). I had NO IDEA what a topographic map was, much less how to teach about it. What was I to do? I couldn't teach something without a basic understanding of it... My first stop? Google. Hundreds of images came up on the screen, lines were everywhere, and I had no idea what I was looking at! As I dove into my study, I realized that while a topographic map appears complicated– it is actually quite simple and brilliant! For those who may have stumbled upon my post because you have found yourself in similar situation– I hope to help you find clarity and confidence! I promise that once you understand more about Topographic Maps and how to use them, you will really enjoy teaching about them. In fact, Topographic Maps are now one of my favorite teaching topics! Seeing your students have that “AHA!” moment while creating their own Topographic Map is the BEST!!!
First things first– What is a Topographic Map?
A Topographic Map is really just a 2-Dimensional representation of our 3-Dimensional Earth’s surface. Okay, now that we got that out of the way– Why in the world do we need them and how do we read them??? Topographic maps help scientists to determine the slope of the Earth’s surface, determine the direction of flow for groundwater, surface water, and mudslides. They show the surface of the earth and its crustal features– hills, depressions, plains, deserts, mountains, etc. They are an integral part of planning construction and are used to research natural resources. The main way that you or your students might utilize them in life would be to reference before hiking or going orienteering. To utilize a Topographic Map, you must first understand what you are looking at– those squiggly lines all over the map? They are important– they are called contour lines and they show areas that have the same elevation. These lines connect and eventually form a closed loop. The distance between contour lines represents the difference in elevation between the points and is called the contour interval. Contour lines that are spaced widely apart represent gradual change in elevation. Contour lines that are spaced closely together represent a steep increase in elevation. The distance between the highest and lowest points of elevation on a map is called the relief. Now you know the basics!
Fun Fact
Did you know that Scientists use sound waves to map the topography of the ocean floor?
Sound waves are sent down and then bounce back from the ocean floor. A receiver picks them up as they are reflected, mapping the depth. How cool is that?!
Word of Warning
While topographic maps are really useful, there is one disadvantage that the user must be aware of. Topographic maps can have information that is dated. Landscapes change over time– due to natural occurring events, weathering, erosion, deposition, and man-made
changes like building roads or excavating. Knowing this, it is crucial that the user check the date of the map they are using. The USGS is constantly adding updated maps to their online archive. These maps are free for use and are in the public domain.
How do I help my students understand Topographic Maps???
Now that you understand and know more about Topographic Maps, how do you help your students understand? I decided I needed to make the idea of topographic maps more concrete for my middle schoolers, so I created an activity that allowed them to build a 3-D
version of their topographic map. Cutting out the layers and building them helped students to see the direct correlation between topographic maps and elevation.
I created a background information sheet for my students to help them build schema. We reviewed vocabulary using a graphic organizer and then after building our 3-D models, students answered questions while reading a topographic map to check for understanding. It was a very successful lesson! You can use this hands-on activity to help your students understand Topographic Mapping and make this abstract concept more concrete. Happy Mapping!!!
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