Jump to main content

Slippery Slopes and Sticking Surfaces: Explore the Forces of Friction

40 reviews


Whoopee! No matter what age, who doesn't like flying down the slides at parks and pools? In this experiment, you might be surprised what you can learn about the fascinating forces of friction while sliding down (or sticking to) those fun, slippery slopes. Caution: only speed demons need apply for this activity.


Areas of Science
Time Required
Short (2-5 days)
Material Availability
Readily available
Very Low (under $20)
Minor injury possible
Darlene Jenkins, Ph.D.

This project is based on a DragonflyTV episode.


The goal of this project is to use a slide to learn about the forces of friction.


Frictional forces surround us. We rub our hands together to generate heat when we're shivering. Screeching tires burn rubber on the road when cars start too quickly or turn too sharply. Meanwhile, special treads on those same tires cling to the road to keep us safe when we travel icy highways. And who hasn't been grateful at least a few times for the traction exerted from rubber-soled running shoes or water sandals in slippery situations?

We all recognize what friction is, but do you really understand what causes it? This project focuses on friction, its causes and forces and specifically how it affects how fast you can slip down slides. We most commonly think of friction in terms of surface roughness, like the resistance of two pieces of sand paper catching between our fingers. But there are also small electromagnetic interactions of atoms and molecules sitting on the surface of even smooth objects that are important in generating friction. These tiny but strong molecular snags are especially apparent between very smooth surfaces like two pieces of plate glass that stubbornly stick to each other if not separated by paper or sheets of plastic. In general, when two objects interact they produce some level of frictional force upon each other determined by their weights and the combination of surface roughness and intermolecular sticking. How much friction the two surfaces produce determines whether the objects move or simply remain in place.

A couple of basic laws of physics describe the forces of friction. You'll learn more about these principles as you complete your background research and run your experiments. But in simple terms, when an object is stuck on a surface, like a heavy box you are trying to push along the floor, scientists describe this as a "static" friction interaction because there is no movement. The weight of the box essentially holds it against the floor and the friction generated between the box and floor's surface is greater than the pushing force trying to move it (you). When your buddy comes along to help you out, the pushing force now becomes greater than the static frictional force and the box slides easily along. However, there still is some resistance from the box because it remains in contact with the floor surface; this moving type of friction is called "kinetic" friction. In general, static friction is greater than kinetic friction and that explains why it sometimes takes a shove to get a heavy box moving, but once it's unstuck, it's easier to keep it sliding along the floor.

In this project, a local playground slide serves as your test site for experimenting with static and kinetic friction. You and a friend will explore how to change the frictional forces that can slow you down or speed you up when you push off and slide down. You'll time your runs and experiment with different materials (e.g., pillowcase, towel, cardboard, carpet, plastic bag) to find out how each "speed mat" interacts with the slide to affect your starts and total times. While we've offered suggestions for the types of materials to try in your experiments, no doubt you'll be able to come up with a few ideas of your own. You'll have to take careful measurements with a stopwatch in these experiments because there might only be a fraction of a second difference between some runs and others.

Good luck, have fun, and watch out below!

Terms and Concepts

To do this project, you should do research that enables you to understand the following terms and concepts: For a more advanced understanding that includes the mathematics of friction, you should research:



  • Introductory site with simple definitions of terms related to friction:
    Kurtus, R., (2006). Resistive Force of Friction. School for Champions. Retrieved April 28, 2007.
  • Basic introduction to a few concepts and mathematical relationships between friction, coefficients of friction, and normal force:
    Nave, C.R., (2005). Friction. HyperPhysics, Department of Physics and Astronomy, Georgia State University. Retrieved April 28, 2007.
  • Good website for high school level lessons on physics and how to use vector diagrams to represent the forces acting on an object:
    Henderson, T., (2004), Force and Its Representation. The Physics Classroom. Retrieved April 28, 2007.
  • This project is based on:
    TPT, (2014, March 5). Luge by Jenn and Emily. DragonflyTV, Twin Cities Public Television. Retrieved Janujary 15, 2018.

Materials and Equipment

To do this experiment you will need the following materials and equipment:

Experimental Procedure

Collecting Your Data
  1. Find a slide to use for your study—the longer the better. Decide which materials you want to use for speed mats in your experiment. Select at least three you think will give you different results.
  2. You should make two different observations for each mat you use in your tests:
    1. The Push Off (Static Friction): Note how much effort it takes to get going down the slide. Try to keep your push offs as consistent as possible (where you place your hands, how many times you push, the position of your legs, etc). This will be a "qualitative" measurement. That means you won't assign a number to it, but instead give a description about each push like an "easy" push was all that was needed to get you moving, or "medium", "hard", or "extra effort" was required.
    2. The Speed (Kinetic Friction): Note the time it takes to get from the top to the bottom of the slide. It's likely that the differences between your tests will be in fractions of a second, so your friend will have to be very good about making careful measurements with the stopwatch. They should start the clock right when you push off, and they should stop the watch the moment they see and hear your feet hit the ground.
    3. Tips: You might try a few trial runs with no mat to practice taking times before you get into your real tests. Also, be sure to not rush too much as you go down the slide so you don't risk falling off or hurting yourself.
  3. Do at least ten runs for each type of mat (more trials would be even better). Record a description of the start and the total time for each run in your notebook.
Analyze Your Data
  1. Calculate the average time for each mat material you used in your tests.
  2. Make a table that shows the average time for each material as well as your description of each start.
  3. Do you see any differences in the times or ease of start for your materials? Were some materials faster or slower by a small or large margin?
  4. Were your results what you expected or were you surprised? If so, how?
  5. For more advanced analysis, make vector diagrams showing the direction and relative magnitude of the friction forces that illustrate the results for each of your test materials.
  6. For help with data analysis and setting up tables, see Data Analysis & Graphs.
  7. For a guide on how to summarize your results and write conclusions based on your data, see Conclusions.
icon scientific method

Ask an Expert

Do you have specific questions about your science project? Our team of volunteer scientists can help. Our Experts won't do the work for you, but they will make suggestions, offer guidance, and help you troubleshoot.


  • Pick one of the fastest materials from your initial experiment to try these variations.
    • Size of contact surface area: sitting vs. lying down; legs straight ahead or tucked onto the mats; taller person vs. shorter person of similar weight.
    • Weight of slider: compare two people of very different weights.
    • Temperature: try your experiment on a hot day and then repeat it on a cold day.
    • Moisture: dry, sunny day versus a foggy day or just after a rain.
  • If you use a concrete slide, try it with and without loose sand on the surface of the slide.
  • If you have multiple slides, made from different materials (e.g., plastic, metal, concrete), you can extend your experiment to include the different slides.
  • For a more quantitative experiment on friction, see the Science Buddies project Effect of Friction on Objects in Motion.


If you like this project, you might enjoy exploring these related careers:

Career Profile
Mechanical engineers are part of your everyday life, designing the spoon you used to eat your breakfast, your breakfast's packaging, the flip-top cap on your toothpaste tube, the zipper on your jacket, the car, bike, or bus you took to school, the chair you sat in, the door handle you grasped and the hinges it opened on, and the ballpoint pen you used to take your test. Virtually every object that you see around you has passed through the hands of a mechanical engineer. Consequently, their… Read more
Career Profile
You use mechanical devices every day—to zip and snap your clothing, open doors, refrigerate and cook your food, get clean water, heat your home, play music, surf the Internet, travel around, and even to brush your teeth. Virtually every object that you see around has been mechanically engineered or designed at some point, requiring the skills of mechanical engineering technicians to create drawings of the product, or to build and test models of the product to find the best design. Read more

News Feed on This Topic

, ,

Cite This Page

General citation information is provided here. Be sure to check the formatting, including capitalization, for the method you are using and update your citation, as needed.

MLA Style

Science Buddies Staff. "Slippery Slopes and Sticking Surfaces: Explore the Forces of Friction." Science Buddies, 11 May 2023, https://www.sciencebuddies.org/science-fair-projects/project-ideas/ApMech_p022/mechanical-engineering/friction-slippery-slopes. Accessed 22 Sep. 2023.

APA Style

Science Buddies Staff. (2023, May 11). Slippery Slopes and Sticking Surfaces: Explore the Forces of Friction. Retrieved from https://www.sciencebuddies.org/science-fair-projects/project-ideas/ApMech_p022/mechanical-engineering/friction-slippery-slopes

Last edit date: 2023-05-11
Free science fair projects.