Lesson Summary

	Students will make inferences about the cause of shadows by observing and making their own shadows in the sun. Many properties of shadows (such as heat and brightness of light) will also be identified firsthand as the students conduct simple experiments to observe changes that are comparable to those experienced by the MESSENGER spacecraft in its voyage to and around Mercury.
The shadow cast by Mars' potato-shaped moon, Phobos. Courtesty of Astronomy Picture of the Day. http://apod.gsfc.nasa.gov/apod/ap991105.html	Take me to the complete lesson Back to Scientific Process Modules

Essential Question

How does the amount of sunlight and heat change in areas that are shades?

Essential Concepts

• Sunlight and other types of light form shadows.
• Shadows form because light travels in straight lines.
• Light cannot pass through some materials and this leads to the formation of shadows.
• Shadows can change position and shape and size depending on the position of the object in relation to the position of the light source.
• Darkness is the absence of light.

MESSENGER Mission Connection

The generation of heat by sunlight ia also why shadows are important for the MESSENGER mission to Mercury. Because the spacecraft will be very close to the Sun, it will receive much more intense sunlight than we get on Earth. To reduce the temperatures in the probes, a sunshade is included on the craft. The spacecraft is oriented so that the shade always faces the Sun, and the sensitive instruments used to make observations of Mercury are always in shadows.