FRICTION!
Overview
This resource provides basic information on four types of friction - sliding, static, rolling, and fluid. It is aimed primarily at an upper elementary or lower middle school curriculum.
Background Information
Friction is all around us! Friction is a force that is trying to slow down the motion of objects. It even tries to stop objects from moving in the first place! In the photograph above, the girl is having a great time sledding down the sand dune at Great Sand Dunes National Park and Preserve. However, friction is trying to slow her down!
There are four main types of friction. These are:
- Sliding Friction
- Static Friction
- Rolling Friction
- Fluid Friction
We will learn about each type in the next several sections.
Sliding Friction
Sliding Friction
Sliding friction is the friction that occurs between two objects sliding over each other. This kind of friction can produce a lot of heat! In the picture below the man used a bow drill to start a fire without matches!
Static Friction
Static friction is the friction between two objects that are not moving. Static friction is trying to keep the object at rest! If you want to push an object and get it sliding, you would have to overcome the static friction. Static friction can often be the strongest frictional force.
In the picture below, the dog and the couch have static friction. It looks like it would take a lot of force to get the dog moving off of the couch!
Rolling Friction
Rolling friction is the force of one object rolling over another. Rolling friction is often a lesser force than static or sliding friction. Think about how the wheel makes life easier! Imagine having to carry all of the vegetables or drag them across the ground on a tarp. The wheel greatly decreases the amount of friction!
Fluid Fricton
Fluid friction is the frictional force when an object is moving through a fluid, which is a gas or liquid. Air resistance is a common form of fluid friction. Think of how hard it is to walk or ride a bicycle in the wind! The fluid friction is trying to slow you down and making it harder to move!
Dogs seem to love the fluid friction of air moving past a car's window!
Review and Assessment
To review, please watch the video titled "Real Life Examples of Friction" by MooMoo Math and Science. Then, answer the questions below. Please write the answers on paper and bring them to class.
Questions from the lesson and video:
- Which kind of friction is often the strongest?
- When you rub your hands together, what kind of friction are you experiencing?
- What kind of friction exists between a stationary refrigerator and the floor?
- What kind of friction exists between a swimmer and the water?
- Give an example of fluid friction from the video.
- Give an example of rolling friction from the video.
- Describe a situation in which you would want to have a higher frictional force. Explain why.
- Describe a situation in which you would want to have a lower frictional force. Explain why.