Science 8 Fall Semester Quiz 1.02 review

Which of the following is an example of how a scientist might use a model?

• Microscopes are used to magnify groups of cells on a slide
• Marbles are placed inside a hollow sphere to describe the protons in a nucleus
• A wrench is used to tighten a nut onto a piece of wood
• Stopwatches are used to measure the amount of time it takes runners to complete a mile

Which of the following is an example of how a scientist might use a model?

• Microscopes are used to magnify groups of cells on a slide
• The end of a slinky is moved vertically up and down to simulate a wave
• A wrench is used to tighten a nut onto a piece of wood
• A stopwatch is used to measure the rate of a chemical reaction

Which of the following represents a system that is completely open?

• a pressure cooker
• a pressurized canister of helium gas
• a pot of boiling water
• a capped soda bottle

Which best explains why a washing machine represents an open system?

• Most washers can use a variety of laundry detergent brands.
• The amount of wash in a load varies.
• It has multiple cycles, such as wash and spin.
• Water and power come from external sources.

Which best explains why a wood-burning fireplace represents an open system?

• because they are not all made of brick
• because they can be used for cooking
• because a fire requires oxygen from the atmosphere to burn
• because the ashes have to be swept away

No system is completely closed off from its surroundings. Which represents a system that is almost completely closed?

• a washing machine
• a wood-burning fire place
• a pot of boiling water
• a capped soda bottle

Which statement best defines a universal law?

• It is in effect some of the time.
• It operates only under specific conditions.
• It is in effect at all times.
• It changes over time.

Why is the law of gravity an example of a universal law?

• Gravity is the attraction of any mass to any other mass.
• Gravity is a force that only affects everyone on Earth.
• Gravity is the reason the Earth revolves around the sun.
• Gravity is a force that exists between any two masses in the universe.

Our understanding of the atom has changed over time. Which idea that was once accepted is now considered scientifically inaccurate?

• The nucleus is the center of the atom.
• An atom is a solid sphere.
• Electrons have a negative charge.
• Electrons are arranged in layers.

The model of the atom has changed over time in light of new knowledge and discoveries. Which option correctly describes one such change?

• In 420 B.C., John Dalton developed the idea that small atoms combined to form molecules.
• About 1900, Neils Bohr developed an atomic model where positively charged particles orbit a negatively charged nucleus.
• About 1900, J.J. Thomson discovered electrons were negatively charged particles.
• About 1915, J.J. Thomson developed an atomic model where negatively charged particles orbit a positively charged nucleus.