MY NASA DATA Science Project Ideas

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Science Project: Make a Sky Mirror to Observe Clouds and Contrails	Image courtesy Forrest M. Mims III
Web Id: P5
Purpose: Provide one method for making a sky mirror to better estimate the fraction of the sky covered by clouds and spreading contrails.
Age Range: 6 - 99
Time Required: About 15 - 20 minutes to complete the Sky Mirror once supplies have been obtained. To get a good feel for the different types of clouds, continue observations for a month or more.
Background: The huge eyes of a dragonfly allow it to see almost the entire sky. Our eyes look straight ahead, and we see only a small portion of the sky. How can we see the sky the way a dragonfly does? Photographers use a 'fisheye' lens to photograph the entire sky at once. These lenses are very expensive. Inexpensive versions sold by hardware stores are designed to be installed in the doors of homes so the occupants can safely see who is knocking on the door or ringing the doorbell. While these lenses can be used to observe the sky, it is best to avoid using them since direct sunlight passing through the lens may damage your eyes. A safer way to observe most of the sky at once is to use a sky mirror. This is my name for a curved mirror designed to be attached to the rearview mirror of a truck so the driver can see around a trailer being pulled by the truck. These mirrors are available in various sizes from automobile parts stores and variety stores. A sky mirror will give you a greatly expanded view of the sky. A sky mirror will also allow you to better estimate the fraction of the sky covered by clouds and spreading contrails.
Significance: A simple but useful technique to facilitate sky cover observations.
Project Links: Sun and Sky Observations at Geronimo Creek Observatory
Real Time Data Source: MODIS Rapid Response System
MY NASA DATA Source: In the Live Access Server: Datasets: Atmosphere: Clouds: Cloud Coverage. Historical data on Monthly Cloud Coverage for a variety of cloud types is available from ISCCP.
Project Ideas: Because all mirrors can reflect sunlight into your eyes, they must be used with great caution. Here are some safety guidelines for using a sky mirror. 1. Never use a flat mirror as a sky mirror. It will not allow you to see more than you can see with your eyes alone, and it may reflect dangerous levels of sunlight into your eyes. 2. Only use curved mirrors for observing the sky. Protect your eyes by wearing dark sunglasses. Stand or sit with your back to the sun, and hold the mirror so that it is in the shadow of your head. This will keep direct sunlight from striking the mirror and being reflected to your eyes. 3. For added protection, place self-adhesive, circular labels across the center of your sky mirror. Should the sun be high in the sky, you can hold the mirror so that the sun is blocked by one of the circles.
Analysis Ideas: You can use a camera to photograph the clouds displayed in a sky mirror. However, be sure that direct sunlight is blocked by either your head or a self-adhesive label attached to the mirror.
Related Projects: Use a marking pen to divide the mirror into 8 slices or oktas. With the sun at your back and while wearing dark sunglasses, place the mirror flat on a table or the ground so that you can see the entire sky while looking at the mirror. If the sun is not blocked by clouds, move your head so that it forms a shadow over the mirror. This will protect your eyes from reflected sunlight. Estimate the number of oktas blocked by clouds.
Questions: How does your cloud coverage estimate using the Sky Mirror vary from your estimate without using the mirror?
Going Further: Some scientists have developed instruments based on this model, which have a camera mounted above the sky mirror that takes regular pictures of the sky.
Project ideas contributed by Forrest M. Mims III

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