Stars, galaxies and the universe

Grade 6 Science Worksheet - Challenge Me

Circle the best answer.

1. Read this first

   Use this

   Nested boxes, not to scale, each box drawn inside the next. Box W: the Sun and its planets. Box X: Box W plus more than 100 billion other stars. Box Y: Box X plus over 50 other galaxies. Box Z: Box Y plus many more groups and clusters of galaxies.

2. 1.

   Box Z, the universe, is about 13.8 billion years old and still expanding (NASA). What is happening to the space between far-apart galaxy clusters, Bo?

   • It stays the same as long ago
   • It shrinks as the universe cools
   • It keeps growing
   • It grows inside our solar system instead
3. 2.

   Esme's classmate draws the Milky Way inside the solar system. Which fix is right?

   • Keep it: the solar system is big enough to hold the whole galaxy
   • Draw the two the same size
   • Swap them: the solar system is a tiny part of the Milky Way
   • Take out the Sun, since it is not a star
4. 3.

   Two stars give off the same amount of light. Star P is 10 light-years away; star Q is 100 light-years away. Which looks brighter from Earth, Jun?

   • They look equally bright
   • Star Q, since 100 light-years is a longer time
   • Star P, the closer one
   • Star Q, the farther one
5. 4.

   Sirius is the brightest star in the night sky (NASA), yet the Sun outshines it by far. Which explanation fits, Kira?

   • The Sun is a planet, so it glows more
   • Sirius is a planet
   • Sirius gives off no light of its own
   • The Sun is far closer to Earth
6. 5.

   Luz reads about a faint star and a bright star that give off the same amount of light. Which claim, with its reason, fits?

   • The faint one is hotter, since faint stars are red
   • The faint one is a planet, since stars are bright
   • The faint one is farther away, so less of its light reaches us
   • The faint one is closer, since faint means near
7. 6.

   Galaxy card: round, no flat disk, made mostly of older stars. Milo must name the shape and one clue. Which answer fits?

   • Elliptical: it has spiral arms
   • Spiral: round, with older stars
   • Elliptical: round, with older stars
   • Irregular: it has no flat disk and no arms
8. 7.

   When two galaxies collide, the stars inside them do not crash into each other (NASA). Why not, Pia?

   • The stars bounce off each other like balls
   • Galaxies have no stars in them
   • Stars are too small to have gravity
   • The stars are very far apart
9. 8.

   Ren's friend says the universe has always looked the same as it does now. Which response is best?

   • Agree: the galaxies have stayed in the same fixed spots since the start
   • Agree: the universe stays the same size
   • Disagree: it began 4.6 billion years ago
   • Disagree: it began hot and dense and has been expanding
10. 9.

    A video says a light-year is how long a year lasts on a far planet. What should Tala write beside it in a class notebook?

    • Right: it is the age of a star
    • Right: it is a time, like a calendar year
    • Not right: it is the speed of a spaceship
    • Not right: a light-year is a distance, about 9.5 trillion km
11. 10.

    Zee's cousin says red stars are the hottest, since red means hot on a stove. Which response fits?

    • Agree: reddish Betelgeuse must be hotter than our yellow Sun
    • Disagree: stars have no temperature
    • Agree: red is the hottest color for stars
    • Disagree: blue stars are hotter; red stars are cooler