8th Grade STAAR Review

The model shows sunlight reaching Earth. Four points are shown on different parts of Earth. Based on the position of Earth in the model, which point is experiencing nighttime during a summer month?

• Position 1

• Position 2

• Position 3

• Position 4

A scientist performed an investigation involving a reaction that produced Al₂(SO₄)_3. How many sulfur atoms are represented in this formula?

• 1 atom

• 3 atoms

• 7 atoms

• 9 atoms

Which statement correctly compares the masses of subatomic particles in an atom such as carbon?

• An electron has a greater mass than a proton.

• A proton has about the same mass as an electron.

• A proton has about the same mass as a neutron.

• Neutrons, protons and electrons has the same mass.

Part of a Periodic Table is shown. In which numbered position would a period 4 element that is a metal with 3 valence electrons be located?

• Position 13

• Position 15

• Position 20

• Position 31

Students were studying the effects of moon positions on tides. When neap tides occur, the difference between the high tide level and low tide level is at its smallest of the tidal cycle. Which model shows a correct arrangement of the Sun, Earth and Moon when neap tides occur?

• B

• D

Four elements are shown as they appear in the Periodic Table. Which statement makes an accurate comparison of some of these elements?

• An atom of Scandium contains two more protons than an atom of Vanadium.

• An atom of chromium contains seven more protons than an atom of Scandium.

• An atom of titanium has fewer protons than an atom of vanadium but more protons than an atom of scandium.

• An atom of chromium contains four more protons than an atom of scandium but only two more protons than an atom of titanium.

A swimmer makes a turn at a pool wall. Which answer choice best describes the direction the swimmer accelerates when she pushes against the wall?

• Away from her push because the wall exerts equal and opposite force.

• Away from her push because the wall exerts a stronger force in the same direction.

• Same direction as her push because the wall exerts an equal force in the same direction.

• Same direction as her push because the wall exerts a stronger and opposite force.

The model shows eight positions of the moon around Earth during the lunar cycle. In which positions would a first quarter moon and last quarter moon appear to an observer on Earth?

• First quarter- position 1

  Last quarter- position 5

• First quarter- position 2

  Last quarter- position 6

• First quarter- position 3

  Last quarter- position 7

• First quarter- position 4

  Last quarter- position 8

Which statement best distinguishes comets from nebulae?

• Nebulae can form stars, but comets cannot.

• Comets are in galaxies, but nebulae are not.

• Nebulae have moons, but comets do not.

• Comets can be part of a constellation, but nebulae cannot.

Part of an identification key for some marine animals is shown. Which statement can be used to describe some characteristics of the narwhal?

• It has tail fins that extend horizontally from its body and it has a tusk.

• It has a dark body, and its tail is half the length of the body.

• It's body coloring is similar to the killer whale's, but it is larger than the killer whale.

• It's head is shaped like a hammer and has a single tusk.