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Exploring Lenses

A lens is a piece of transparent material with at least one curved surface, which refracts, or bends, light rays coming from an object. Lenses are important in optical devices that use light, including our eyes, cameras, telescopes, binoculars, microscopes, and projectors. Encourage students to learn about lenses by examining them firsthand and observing their similarities and differences. Discovering the characteristics of the different lenses will help your students complete Activity 5, which concentrates only on convex and concave lenses.

Required Materials

  • Science notebooks
  • Sets of lenses
  • Flashlights

What will the students do?

In pairs or small groups, students will look at various lenses. In their science notebooks, students will write a description of what each lens looks like, what objects look like when viewed through the lens, and other information that they decide is necessary to enhance their understanding of how lenses change the way we look at objects. Students will brainstorm with classmates about uses for the various lenses, answering the following questions: How would a scientist use each lens? What instruments can you think of that might use the lenses you looked at?

Activity Extensions

Research - Have students use a variety of media to compile a list of scientific instruments and tools that use lenses. Students should then list the types of lenses used in each and compare them to the lenses they have examined.

Reading - There are hundreds of American women who kept the lamps burning in lighthouses. Most of these women served in the nineteenth century, when the keeper lit a number of lamps in the tower at dusk, replenished their fuel or replaced them at midnight, and every morning polished the lamps and lanterns to keep their lights shining brightly. Several of these women were commended for their courage in remaining at their posts through severe storms and hurricanes. A few even went to the rescue of seamen when ships capsized or were wrecked. Their varied stories provide a unique picture of maritime history. Read excerpts from the book, Women Who Kept the Lights: An Illustrated History of Female Lighthouse Keepers by Mary Louise Clifford and Candace Clifford (ISBN: 0963641204) to students or require them to research and explore the lives of some of the more important women on their own. After learning about these women, students could then write a diary entry describing the daily life of a lighthouse keeper during this time.

Narrative writing - Use the following expository writing prompt: Key West, Florida, has a Wreckers' Museum that tells about how early residents of Key West purposely tried to wreck ships. Think about reasons why someone who lived in an isolated area would want to wreck a ship. Now write a description of what you imagine life as a child of a "wrecker" would be like.

Discussion - Have students determine how life as a lighthouse keeper could be enhanced by technological developments of the last decade (for example, e-mail and the internet). Encourage them to discuss and develop answers for the following questions: How might life have been different for "wreckers?" Would lighthouse keeping be a more popular career choice if keepers had access to these technological advances?

Historical Vignette: Ida Lewis

Idawalley Zorada Lewis, called Ida, was born in Newport, Rhode Island, in 1842. Her father, Captain Hosea Lewis, was a coast pilot and became the first keeper of the Lime Rock beacon on a tiny island near Newport. Shortly after he started this job he had a stroke, and Ida Lewis became responsible for the care of her father and of the light. She filled the lamp with oil at sundown and again at midnight, trimmed the wick, polished the carbon off the reflectors, and extinguished the light at dawn. After her father died, she received an official appointment as lighthouse keeper and continued at that post until she died in 1911.

Because of the many rescues for which she was responsible, Lewis became the most famous lighthouse keeper of her day. During her 39 years on Lime Rock, she is credited with saving 18 lives, although unofficial reports suggests that the number may have been as high as 25. Her last recorded rescue occurred when she was 63 years old. Many of the newspapers and magazines of the day wrote stories about some of her rescues. President Ulysses S. Grant and Vice President Schuyler Colvax even went to visit her in 1869.

In 1881 the Annual Report of the U.S. Life Saving Service reported that the highest medal awarded by the Life Saving Service had been presented to Mrs. Ida Lewis-Wilson. Then, in 1924 the Rhode Island legislature officially changed the name of Lime Rock to Ida Lewis Rock. Similarly, the lighthouse service changed the name of the Lime Rock Lighthouse to the Ida Lewis Lighthouse, the only such honor ever paid to a keeper.

Activity - Encourage your class to research lighthouses and, if possible, take a field trip to one that is nearby. Have students record similarities and differences among lighthouses that are found in different areas. For instance, lighthouses in southern coastal states can be compared with lighthouses on New England's rocky coast or European lighthouses can be compared with American ones.

Artist Vignette: Winslow Homer

Winslow Homer (1836-1910) was an American artist most remembered for his New England seascapes, who worked in a variety of media. He created oil paintings of rural early America, was a magazine illustrator of Civil War scenes, and used watercolors to produce his heroic scenes of the sea. He created hundreds of works that are admired for their beauty and depiction of rural American life. Lesser known than his seascapes is a series of tropical watercolors that reflected his winter stays in Florida, the Bahamas, and Cuba.

Homer had a robust sense of humor that is well documented. When visitors came to his studio, he often made his own illustrations the butt of his jokes. In fact, once he put a tin tag on one of his sketches as a hog's nose; when his visitor was not looking, the "nose" became a setting sun. Also, at the beginning of a path that led to Cannon Rock, one of Homer's favorite spots to paint, he placed a sign that said "SNAKES! MICE!" so that he would not be disturbed.

Activity - Recently Bill Gates, Chairman of Microsoft, paid a record $30 million for Winslow Homer's last seascape still in a private collection, Lost on the Grand Banks. The sale was a private one and was kept a secret until the deal was struck. Have students debate the issue of private versus public art collections and the value of each. You may wish to divide your class into two groups and have them brainstorm the points that they will make in order to defend their position.

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