by Lauren Harris & Harini Ramireddy

“ To truly understand and prove the validity of Newton’s law of Cooling”

The Purposeof Our Investigation

• Background of the Mathematician

• The Experiment and Devices Used

• Theories Concerning this Law

History English physicist,

mathematician, and natural philosopher

Born in Lincolnshire, England in mid-seventeenth century to a farming family

Attended Cambridge College

of Sir Isaac Newton(1642–1727)

Accomplishments• Laws of Motion

• Laws of Universal

Gravitation

• Philosophiae Naturalis Principia Mathematica

• Determination of the speed of sound in air, Newton’s Method, etc.

Newton’s Other

• Modern Study of Optics

• Scala Graduum Calories

• Involved in the development of Calculus

Newton Thermometer

• Long glass stem with a hollow bulb on the bottom

• Filled with linseed oil opposed to mercury: different benefits

• Use of the Celsius scale

• amber color

• high boiling point

• coefficient of expansion

• “Reference temperatures”

• Its solution, by the law of exponential change is Newton’s Law of Cooling:

sTTkdt

dT

Newton’s Law of Cooling?

What is

ss TTkTTdt

d

ktss eTTTT 0

• Newton's Law of Cooling states that the rate of change of the

temperature of an object is proportional to the difference between its

own temperature and the ambient temperature.

• If T is the temperature of the object at time t, and Ts is the

surrounding temperature, then:

• Since d T=d (T-Ts) , the above equation can be rewritten as:

Misleading Data• When graphed upon a scale of

temperature difference ratio versus time, the data does not follow the trend assumed by Newton

• Results obtained by Newton’s experiments do not follow a straight line; they follow a curve with a gradually decreasing slope.

• Newton’s own data using his unique device was skewed!

The Two Reasons

Linseed oil cooled faster in the stem of the thermometer than in the bulb

Convection currents within the thermometer

Why Newton’s Data was Misleading

1.

2. surface-area/volume ratio was roughly three times greater in the stem than in the bulb

currents caused mixing of the cooler oil in the stem with the warmer oil in the bulb

How Do We Fix These Problems?

Why do we care?• discovery that the data from Newton’s own thermometer did not

support his own Law of Cooling leads one to question whether it is

truly applicable

• fortunately, his theory and equations have been proven many times over and have been found to be accurate .

• it is fascinating that even though Newton created a unique device to test his hypothesis about temperature change, his data did not follow assumptions!

* We believe that one must consider all aspects of a mathematician’s life and past work to fully conclude whether or not his ideas are valid in the study of calculus

THE END.