Lesson plan: Jupiter's moon Io

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Objectives

Students will:

• Complete an experiment that illustrates the Earth's tidal bulge.
• Define and give examples of gravity.
• Differentiate between the Earth's gravitational pull and that of Io.
• Research tides on water and land.

Standards

National Science Education Standards

Gravity is a universal force that mass exerts on other mass. The strength of the gravitational attractive force between two masses is proportional to the masses and inversely proportional to the square of the distance between them.

Suggested time

2-3 class periods

Materials

CNNfyi article, "By the light of the fiery moon"
"Turning the tides" lab investigation (from Holt, Rinehart & Winston)
Internet access

Procedure

1. Facilitate a class discussion about gravity. Have students consider the following questions:

• What are the gravitational forces affecting the planets and satellites in the solar system? How do these affect us on a daily basis? Can you think of any realistic changes that could occur in the system that would affect us on Earth? What are they? What impact would they have?

• How were the close-up images of Io taken? What produces the yellow, green and red displays? Is this display hazardous to the Galileo spacecraft? Why or why not? According to planetary geologist Alfred McEwen, what triggers the volcanoes on Io and why?
• Name the moons of Jupiter. Why is Io shrinking at such an alarming rate?
• Discuss gravity as it relates to tides. McEwen says, "Every point on Io goes from high tide to low tide, with its rocky surface rising and falling by up to 300 feet or more." Direct students to the quote above, then ask: Can you imagine being present during such an event? What can you compare this to? How do you explain this phenomenon?

Evaluation

Examine the students' representational models created using the lab investigation. Discuss with students the fact that the number of moons a planet has affects its gravitational force. Share with them the fact that Io is in the middle of a number of gravitational pulls. Direct students to present their findings to the class, displaying their lab models and explaining the examples they found during their research.