Review It

Now that you have had some practice determining the central idea by examining key details, let’s review how key details help to convey the central idea.

Reread the first paragraph in “They Never Game Up” below:

The new Nobel award winners worked for years to achieve blue LEDs. When combined with red and green LEDs, they can create white light. Red and green LEDs have been around since the 1960s. Creating blue LEDs took about another 30 years.

Newsela Opens a new window, October 8, 2014

The author uses details in this paragraph to explain how long it took the Nobel award winners to create the blue LEDs. The fact that it took 30 years before blue LEDs were created gives the reader a sense of the perseverance that might have been involved in such a discovery. Thirty years is a long time to be dedicated to a project.

Reread the second paragraph below:

“A lot of big companies really tried to do this and they failed,” said Nobel committee member Per Delsing in Sweden. “But these guys persisted and they tried and tried again and eventually they actually succeeded.”

Opens a new windowNewsela, October 8, 2014

The author uses a quote from a Nobel committee member to describe how the scientists persisted until they succeeded. The fact that big companies tried and failed, but a team of three men persisted and succeeded speaks to the significant of their achievement.

The details in the first two paragraphs convey the central idea that the scientists were persistent and never gave up in their discovery and kept trying until they succeeded.

Reread the third paragraph below:

The achievement required the growth of high-quality crystals, used as semiconductors. The team grew the crystals from gallium nitride, a semiconductor that produces blue light. Semiconductors allow electricity to flow between a conductor, such as copper, and an insulator, like glass.

Newsela Opens a new window, October 8, 2014

The information in this paragraph provides an explanation of how the blue LEDs were achieved. While this information may be helpful for those who want to understand the science behind the LEDs, it does not provide key ideas to convey or support the central idea of this section. As seen in the first two paragraphs, this section is mostly about the persistence of the scientists.

Read the subtitle, the title that introduces the new section of text: “They Never Gave Up.”

This subtitle, which you read before reading the section, was a text feature that the author used to tell you what to expect in your reading. When you read the subtitle, you most likely had questions about the challenges that the scientists faced that the section answered.

Now go to the next page to test your ability to determine the central idea for another section of the text.