Science 8th Grade

2.Mr. Lee used a globe to demonstrate to his class that Earth rotates around a central line. He also demonstrated that Earth travels around the sun by picking up the globe and walking in a circle around his desk. It takes Earth one year to make one trip around the sun. What word is used to describe one object moving around another object?

• A. Orbit

• B. Gravity

• C. Rotation

• D. Revolution

3.Karina is conducting an experiment based on Isaac Newton's law of universal gravitation. She is testing the strength of the force of gravity between two objects. What factors determine the strength of the force of gravity? Choose the two that apply.

• A. Distance between the objects.

• B. Sizes of the objects.

• C. Masses of the objects

• D. Weights of the objects

Kevin is taking a meteorology class in which he studies weather and climate. He learns that Earth's position

relative to the sun determines the seasons. For example, more sun shines on the Northern Hemisphere in July than in December. Write the letter of the correct answer on the line at left.

4. Why does the sun shine more directly on Earth’s Northern Hemisphere during the summer months?

• A. The rotation of the sun makes temperatures warmer.

• B. The tilt of Earth's axis tips the Northern Hemisphere toward the sun.

• C. The gravitational pull toward the sun is stronger in August.

• D. Earth's orbit is nearest to the sun in the summer.

6.Rachel reads about how astronauts appear to be weightless in space. She wonders how Earth stays in orbit around the sun when astronauts float while in orbit around Earth. She remembers that there is a force that keeps Earth in orbit around the sun. This force is the same force that keeps astronauts in orbit around the Earth. It also helps to explain why they appear to be weightless. What is this force?

• A. Gravity

• B. Motion

• C. Speed

• D. Weight

1. Early astronomers proposed many theories about the objects they saw in the sky. Using these theories, they tried

to explain the location and movement of these objects. The diagram below shows one theory about Earth and its

neighbors in space. Which theory does this diagram illustrate?

• A. Ptolemy’s Theory.

• B. Aristotle’s Theory.

• C. Geocentric Theory.

• D. Heliocentric theory.

2. How does Aristarchus’ view of the Solar System compare with Aristotle’s view?

• A. Their theories do not differ, because they are both geocentric.

• B. Their theories do not differ, because they are both heliocentric.

• C. Aristarchus’ theory is geocentric, and Aristotle’s theory is heliocentric.

• D. Aristarchus’ theory is heliocentric, and Aristotle’s theory is geocentric.

3. Johannes Kepler mathematically determined the motion of planets in our solar system. He stated those results in

his laws of planetary motion. According to these laws, how do planets move in the solar system?

• A. Circular orbits around Earth

• B. Elliptical orbits around Earth

• C. Circular orbits around the sun

• D. Elliptical orbits around the sun

4. Galileo used a telescope to observe Venus. The diagram below explains what he saw. What did Galileo conclude from his observations of Venus?

• A. It is always lit.

• B. It travels around the sun.

• C. It is farther from the sun than Earth is.

• D. It has moons and the moons have phases.

5. Which phrase best describes the HELIOCENTRIC MODEL of the solar system?

• A. Moon-centered.

• B. Earth-centered

• C. Sun-centered

• D. Planet-centered

6. Which of these tools enabled Galileo to study parts of the universe that had never been seen?

• A. Compass

• B. Geometry

• C. Mathematics

• D. Telescope