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.