Pluto Vs Neptune - Farthest from the Sun

The Titius-Bode Law
This law is a rough rule that predicts the spacing of the planets in the Solar System.. The relationship was first pointed out by Johann Titius in 1766 and was formulated as a mathematical expression by J.E. Bode in 1778.� The law relates the distances of the planets to a mathematic progression of numbers.� First assign 10 numbers in the sequence 0,3,6,12.....(doubling each number to get the next).� Add 4 to each number and then divide by 10. Compare these numbers to the distance of each of the planets from the sun in astronoimical units (AU).� Make a data table.� What do you notice?� Why did this lead astronomers in the early 1800's to scan the night sky for the existence of another planet between Mars and Jupiter?� What did they find? Uranus was discovered in 1781 and Neptune in 1846.� How well do these fit Bode's Law?� Although the law has no theorectical basis, it formed part of the drive to look for a ninth planet.� How does the position of Pluto fit Bode's Law?

EXTENSION:
Research the life of Clyde Tombaugh, the discoverer of Pluto.� Read both about his personal life and the work done by him and others that led to his discovery.� Write a letter Tombaugh may have written to a friend, family member or colleague after the discovery of Pluto in 1930.

Clyde Tombaugh 1906-1997

Rock and Roll Minor Planets - online or research activity
When asteroids were first discovered they were given names from Roman and Greek mythology.� Now, however, with over 7000 known asteroids, this supply of names fell short.� Describe how asteroids or minor planets are named.� Record the description of an asteroid with an interesting name.

Impact Craters - laboratory activity
Design and conduct an experiment to determine what factors affect the size and shape of craters.� Things that can be measured are the average length of ejecta rays, the depth of the crater and the diameter of the crater.��� Include numerical data and sketches.� Write a formal lab report including a purpose, hypothesis, procedure, data and observations, data analysis (graphs and calculations), and conclusion.� A surface for this activity can be prepared from flour, a 1:1 ratio of baking soda and salt or a 1:1 ratio of sand and cornstarch.� A thin layer of coffee grounds or powdered drink mix over the surface helps make the features of the craters more visible.

-online or research activity
Research the following questions about comets.� Record your findings.� What causes a comets tail?�� How are comets observed?� What is the association between comets and meteor showers?� What is a comet made of?� Make a comet and describe the results and play the game on this website.� Choose a famous comet to write about.

Asteroid and Comet Impact Hazards - online or reasearch activity
Describe the Torino Impact Hazard Scale.� Summarize the purpose of the NASA NEAR Mission.� Play the National Geographic impact game.� Take notes on the information given about each impact site and describe how you knew which object was the culprit.

EXTENSION:
Many many more activities may be found in Exploring Meteorite Mysteries, a downloadable guide from NASA.