In this investigation, students use "point-source" light, light meters, and graphing software to quantify the reduction in light over distance. Through careful measurement of light received at several distances, students discover the best fit of the... (View More) data is the inverse square rule. Using this rule, students then calculate the distance between the light source and the light meter at random placements. Finally, students extend this principle to model the manner in which distances to Cepheid variable stars are measured. The distance between the Cepheid (here the light source) and the Earth (the light meter) can be determined by comparing the output of the source to the amount of light received. An historic scientific breakthrough occurred when the period-luminosity relationship of Cepheids was quantified throughout the early 1900s. This breakthrough allowed astronomers to gain a more correct understanding of the dimensions of our galaxy and the universe beyond. This activity is part of the "Cosmic Times" teacher's guide and is intended to be used in conjunction with the 1929 Cosmic Times Poster. (View Less)

This collection of activities presents learners with intriguing questions about the universe and provides an opportunity to explore topics related to the search for life beyond our own planet. The collection includes eight existing classroom... (View More) activities that have been adapted for after school school settings. Each activity can be completed in one hour, however some activities require advance preparation. The activities also require materials that may need to be gathered by the instructor. However, these include commonly available supplies. The activities in this collection are targeted for 5-12 year olds. Separate instructions for the different age groups are provided as appropriate. (View Less)

In this activity, students will use a simulator of an orbiting X-ray observatory to observe a supernova remnant, the expanding gas from an exploded star. They will take X-ray spectral data, analyze them, and answer questions based on that data. This... (View More) resource consists of a manual and software for the Introductory Astronomy Lab Exercise, from CLEA (Contemporary Laboratory Experiments in Astronomy). The manual includes introductory activities for students, background information, an instructor's guide, a student handout, an answer key, a software user's guide, and a glossary. The student section of the activity starts on page 13. See Related & Supplemental Resources for a link to download the software. Note: the software is only available for Windows. (View Less)

Gamma-ray bursts are distant explosions that briefly outshine the rest of the gamma-ray universe. In this lesson, students will follow the same procedures used by today's astronomers to determine two basic facts about gamma-ray bursts: their... (View More) distance from Earth and their power. (View Less)