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NASA (James Webb Space Telescope); NASA/Chris Gunn (Space Telescope)
Math,

New Space Telescope

The James Webb Space Telescope will help astronomers see the first stars in the universe

By Jessica McKenna-Ratjen
From the February 2022 Issue

Learning Objective: Students will use area models to find equivalent fractions representing parts of the new James Webb Space Telescope.

Lexile: 920L; 700L
Focus Area: Fractions and Decimals,
Standards
  • CCSS: 3.NF.A.3.B TEKS: 3.3F

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Lexile® measure

  • 920L
  • 700L

NASA (James Webb Space Telescope); NASA/Chris Gunn (Space Telescope)

Last winter, a telescope was launched into orbit 1.5 million kilometers (930,000 miles) above Earth. This telescope, known as the James Webb Space Telescope, is the largest telescope ever sent to space. It was designed to give astronomers a glimpse of something no one has ever seen before: the birth of the universe!

The first large space telescope was the Hubble Space Telescope, launched in 1990. Hubble’s pictures have led to many discoveries. But Hubble isn’t able to detect light from the universe’s formation, which scientists believe happened 13.8 billion years ago.

Scientists launched a telescope into space last winter. The telescope went into orbit 1.5 million kilometers above Earth. That’s 930,000 miles! This telescope is known as the James Webb Space Telescope. It is the largest telescope ever sent to space. Scientists designed the James Webb Space Telescope to allow astronomers to see something no one has ever seen before: the birth of the universe!

The first large space telescope was the Hubble Space Telescope. Hubble was launched into space in 1990. Scientists have made many discoveries using the pictures Hubble took. But Hubble is not able to detect light from the universe’s formation. Scientists believe the universe was formed 13.8 billion years ago.

“Hubble can see back to the universe’s teenage years,” says Stefanie Milam. She’s a scientist who works with the Webb telescope. “We want to see the universe’s infancy.”

Hubble’s view is limited because the universe is expanding. As ancient galaxies move away from us, the visible light they give off shifts into a different type of light called infrared. Infrared light is invisible to the human eye—and to Hubble.

“Hubble can see back to the universe’s teenage years,” says Stefanie Milam. Milam is a scientist. She works with the Webb telescope. “We want to see the universe’s infancy.”

Hubble’s view is limited because the universe is expanding. Galaxies are always moving away from us. The oldest galaxies are very far away. We see visible light from galaxies when they are closer to us. But this visible light changes into a different type of light as the galaxies move farther away. This different type of light is called infrared. Infrared light is invisible to the human eye. It is also invisible to Hubble.

NASA (James Webb Space Telescope); NASA/Chris Gunn (Space Telescope)

The Webb telescope is 3 stories tall and weighs 6 tons!

The Webb telescope specializes in detecting infrared. Because light from distant galaxies is extremely faint, Webb needs a gigantic mirror to detect it. Webb’s mirror is 6.3 meters (21 feet) in diameter (side to side)!

Astronomers plan to use  Webb to explore exoplanets, or planets outside our solar system. But Webb’s most exciting discoveries might end up being things no one imagined.

“We’re about to enter a whole new era,” says Milam.

The Webb telescope is good at detecting infrared. Light from distant galaxies is extremely faint. Webb needs a very big mirror to detect it. Webb’s mirror is 6.3 meters in diameter, or from one side to another. That’s 21 feet wide!

Astronomers also plan to use Webb to explore exoplanets. Exoplanets are planets outside our solar system. But Webb’s most exciting discoveries might be unexpected.

“We’re about to enter a whole new era,” says Milam.

Math Talk

Why would it be important for a telescope-building team to include a mathematician?

Math Talk

Why would it be important for a telescope-building team to include a mathematician?

Equivalent Fractions

What to Do

Two fractions are equivalent, or equal, when they describe the same amount of the whole but have different numerators (top numbers of fractions) and denominators (bottom numbers of fractions). Area models can help you visualize equivalent fractions.

Example

Find an equivalent fraction for  with a denominator of 10.


First, draw an area model to represent 1/5.


The denominator tells you how many equal parts to divide the model into. The numerator tells you how many parts to shade in.

Next, change the model to represent the new denominator: 10. You can draw a horizontal line to split the 5 columns into 10 equal parts. Count the number of parts that are shaded now.

So 1/5 is equal to 2/10.

Equivalent Fractions

What to Do

Two fractions are equivalent, or equal, when they describe the same amount of the whole but have different numerators (top numbers of fractions) and denominators (bottom numbers of fractions). Area models can help you visualize equivalent fractions.

Example

Find an equivalent fraction for  with a denominator of 10.


First, draw an area model to represent 1/5.


The denominator tells you how many equal parts to divide the model into. The numerator tells you how many parts to shade in.

Next, change the model to represent the new denominator: 10. You can draw a horizontal line to split the 5 columns into 10 equal parts. Count the number of parts that are shaded now.

So 1/5 is equal to 2/10.

Now You Try It

Use your knowledge of equivalent fractions to answer the questions below.

Use your knowledge of equivalent fractions to answer the questions below.

A. The James Webb Space telescope has a rectangular sunshield to protect it from the sun’s heat. The sunshield’s width is about 2/3 of its length. Which model below represents 2/3?

B. Draw a line through the model you chose so that it represents an equivalent fraction with a denominator of 6.

C. What is the equivalent fraction you created? 

A. The James Webb Space telescope has a rectangular sunshield to protect it from the sun’s heat. The sunshield’s width is about 2/3 of its length. Which model below represents 2/3 ?

B. Draw a line through the model you chose so that it represents an equivalent fraction with a denominator of 6.

C. What is the equivalent fraction you created? 

Three rows of blocks labeled A, B, and C with some blocks colored in and some not

A. Webb’s honeycomb-shaped mirror is made up of 18 hexagonal parts. Each part has a side length of 3/4 meters. Which model shows a fraction that’s equivalent to 3/4?

B. Write a fraction that is equivalent to 3/4 and has a denominator of 16.

A. Webb’s honeycomb-shaped mirror is made up of 18 hexagonal parts. Each part has a side length of 3/4 meters. Which model shows a fraction that’s equivalent to 3/4?

B. Write a fraction that is equivalent to 3/4 and has a denominator of 16.

Three rows of blocks labeled A, B, and C with some blocks colored in and some not

For the launch into space, Webb’s sunshield was folded down to a little more than  of its full area. On a separate sheet of paper, draw models to find two equivalent fractions for 1/12. Explain why all three fractions are equivalent.

For the launch into space, Webb’s sunshield was folded down to a little more than  of its full area. On a separate sheet of paper, draw models to find two equivalent fractions for 1/12. Explain why all three fractions are equivalent.

Continue Your Learning

  • Rewatch the video “Readying the Webb Telescope for Launch” (above). Then imagine you are building a space telescope of your own. What will you search for with your telescope? How big will it need to be? How far will it see? Create a poster that includes a labeled diagram of your telescope and a brief description of its features. Include at least 5 math facts on your poster.
  • Play an equivalent fraction game! Choose a unit fraction (1/2, 1/3, 1/4, etc.) . Write down 3 fractions that are equivalent to the fraction you chose and 1 fraction that is not equivalent. Then challenge a friend or family member to find the fraction that isn’t equivalent. After your partner answers correctly, it’s their turn to create an equivalent fraction set for you.

Continue Your Learning

  • Rewatch the video “Readying the Webb Telescope for Launch” (above). Then imagine you are building a space telescope of your own. What will you search for with your telescope? How big will it need to be? How far will it see? Create a poster that includes a labeled diagram of your telescope and a brief description of its features. Include at least 5 math facts on your poster.
  • Play an equivalent fraction game! Choose a unit fraction (1/2, 1/3, 1/4, etc.) . Write down 3 fractions that are equivalent to the fraction you chose and 1 fraction that is not equivalent. Then challenge a friend or family member to find the fraction that isn’t equivalent. After your partner answers correctly, it’s their turn to create an equivalent fraction set for you.
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