The document discusses different types of forces and friction. It begins by asking about balanced and unbalanced forces on a book sitting on a desk. It then lists several scenarios involving objects in motion and asks about similarities between them. The document goes on to define friction as the force between two surfaces in contact, and identifies the two main factors that affect friction as the pressure between surfaces and their material composition. It outlines the four types of friction - static, sliding, rolling, and fluid friction - and provides examples of each type.

1. Daily Science
1. If a book is sitting on a desk would it be a
balanced force or unbalanced force? Using
arrows, show what forces are acting on the
book.
2.How would you make the book become
unbalanced if it’s balanced.

2. Scenarios
What are the similarities between each
scenario:
•You sitting in a chair
•Puck gliding across the rink
•Brakes stopping a car
•Football players colliding
•Tires screeching across the pavement
•Riding your bike
•Surfing on some killer waves

3. What is friction?
• Friction is a force that two surfaces exert
on each other when they rub against each
other.
• What two factors do you think affect
friction?

4. Two factors that affect friction.
• The first factor is how hard the surfaces
push together.
• Ex. Rubbing your hands together, the
harder you rub your hands the warmer
they get.
• The second factor is the types of surfaces
involved.
• Would you rather rub your face with sand
paper or wax paper?

5. Types of Friction
• There are four types of friction:
1. Static Friction
2. Sliding Friction
3. Rolling Friction
4. Fluid Friction

6. Static Friction
• Static Friction is when friction is acting on
objects that aren’t moving.
• What could be some examples of this?
• Example: desk not moving, standing still,
pencil laying on desk.
• The objects aren’t moving because of
friction.

7. Sliding Friction
• Sliding Friction occurs when two solid
surfaces slide over each other.
• How can this be useful?
• Spreading sand on ice for more traction,
using your brakes on your bike to stop.
• How can this not be useful?
• Slipping and falling on ice, falling off bike
and skinning your knee.

8. Rolling Friction
• Rolling friction is when objects roll across
something. This provides rolling friction.
• What are some examples of rolling
friction?
• Skateboard, rollerblades
• What do scientist use to reduce the
amount of friction in wheels?
• They use ball bearings.

9. Fluid Friction
• Fluid friction occurs when a solid object
moves through a fluid.
• Some types of fluids are water, air, and oil.
• What are some examples of fluid friction?
• Surfing
• How is riding a bike an example of fluid
friction.
• A cyclists cuts through the air.

10. Fluid Friction
• Fluid friction occurs when a solid object
moves through a fluid.
• Some types of fluids are water, air, and oil.
• What are some examples of fluid friction?
• Surfing
• How is riding a bike an example of fluid
friction.
• A cyclists cuts through the air.