# Do heavier objects roll faster?

You can help youth experience the excitement of science exploration by experimenting whether heavier objects roll faster.

Do heavier objects roll faster? Are you sure? How could you test it out? Encourage youth to answer the question and begin exploring multiple ways to test their answer, which is known as a hypothesis. Do not answer questions posed by the youth, but be part of the conversation; capture the brainstorming and ask questions to redirect or focus the discussion so youth can move on to designing and testing their answers. In the beginning, you may need to provide more guidance and support, but this will change as youth gain confidence in their STEM (Science, Technology, Engineering and Mathematics) skills and abilities. Help youth evaluate initial experiment designs so they are realistic for the time and materials available. An initial exploration can always be expanded or enhanced at a later date as the interest of the youth dictates. Remember, your role is to help youth explore their world!

To help youth explore whether heavier objects roll faster, you will need a ramp and similar objects that roll but have different masses, like an empty bottle and a full water bottle. Adjust the angle of the ramp so the bottles will roll well, but can be timed. Mark a finish line a few feet from the bottom of the ramp and the starting line at the top of the ramp. Place the two items at the starting line and release them at exactly the same time. Watch carefully and record the time each object crosses the finish line. Repeat at least five times – these different trials are called replicates and lead to a more reliable, reproducible explanation or design.

Talk about what the youth saw. Did the heavier items roll faster? Why or why not? Did your data support your original hypothesis? Why do things roll down the ramp rather than up? After discussing the results and coming to a conclusion, you can stop and move to the exploration of another question or take the conversation deeper.

Taking the conversation deeper involves some research by the youth into scientific theories. The goal is to connect the experimental conclusion to an existing scientific theory or multiple theories. Building on our question of whether heavier objects roll faster, youth can explore verbal and mathematical definitions of velocity, acceleration, mass and time. For example, velocity (speed) is a scientific theory and is defined as the relationship between the distance an object travels and the amount of time it takes to travel in that distance. Velocity can be mathematically defined by the formula V=d/t where d = the distance traveled and t = the time elapsed.

Would the angle of your ramp affect the speed? Could you change the angle, record your information and create a graph or equation to predict the speed based on the angle?

After their research, encourage youth to explore their original experiment using their existing data and collecting additional data as needed to verify whether their original conclusion agrees with the existing scientific theory or not.

Engaging youth in an exploration of their world will help them build skills and abilities useful throughout their life, whether they plan to be a scientist or not. Remember, the goal is exploration of our world, NOT the correct answer.

Astrophysicist Neil DeGrasse Tyson recognized the knowledge we have gained over the years is often through mistakes when he said, “It was the work of generations of searchers who took five simple rules to heart…and perhaps the most important rule of all, (5) Remember: you could be wrong. Even the best scientists have been wrong about things. Newton, Einstein and every other great scientist in history – they all made mistakes. Of course they did. They were human.”

4-H science is dedicated to helping you grow the next generations of searchers exploring their world. To learn more about the Scientific and Engineering Practices, go to the Michigan State University Extension website and explore the “Helping youth succeed in science” series. You can also download a free copy of “Framework for K-12 Science Education: Practices, Crosscutting Concepts, and Core Ideas” or Appendix F - Science and Engineering Practices on the Next Generation Science Standards. To learn about more ways to engage youth in STEM, explore “4-H Science: Asking Questions and Discovering Questions” on the MSU Extension website.