Spectacular Science

Presentation by Daniel Riedinger

Teacher Reseda HS Police Magnet

Friction

• What is it• Opposes motion• empirical laws of

friction first investigated more than five hundred years ago by Leonardo da Vinci

Types of Friction

• Sliding Friction: friction produced when two solid objects slide over each other.

• Rolling Friction: friction produced when an object rolls over a surface.

• Fluid Friction: friction produced when an object moves through a fluid.

Is Friction a Good Thing or a Bad

Thing?

What Affects Friction

• Surface type and weight• Force from friction/weight of object =• A constant number• f / N = µ the coefficient of friction• f = µ N• What about surface area?• Friction is independent of surface area

Tornadoes

• Whirling funnel shaped cyclone

• Common on the great plains during spring

• Up to 300 mph winds

Tornadoes

• Tornados are the smallest, most violent, and shortest lived severe storm.

• When a thunderstorm encounters high altitude, horizontal winds, a tornado can be formed.

• These winds can cause the rising air in the thunderstorm to start rotating.

• A narrow funnel shaped, rapidly spinning extension may develop in the cloud.

• Tornados generally cover a path of about 100m wide, destroying everything in their path.

• The tremendous speeds of the winds in a tornado are responsible for the destruction they cause.

• The falling of debris when a home is destroyed or being struck by flying objects causes most deaths and injuries.

• It is very important to find cover in a low place.

Worst Tornado

• March 18, 1925

• Started in Missouri, ended in Indiana• Forward speed was a record setting

73mph • For over 100 miles, the path was

about three quarters of a mile wide• 2027 injured, 695 dead