Scientific Investigations
What is a hypothesis?
A testable prediction or proposed explanation that can be investigated.
What force attracts objects with mass toward one another?
Gravity.
Which planet is the largest in our solar system?
Jupiter.
Approximately how old is the universe?
13.8 billion years.
Which visible-light color has the shortest wavelength?
Violet.
In an experiment, what is the variable that scientists deliberately change?
The independent variable.
Two planets have the same mass. One is closer to a star. Which experiences greater gravitational attraction from the star?
The closer planet.
Which planet is closest to Earth in size?
Venus.
Describe the temperature and density of the universe during its earliest moments.
Extremely hot and dense.
Which has a higher frequency: ultraviolet or infrared radiation?
Ultraviolet radiation.
Students test how water temperature affects how quickly sugar dissolves. What is the dependent variable?
The time required for the sugar to dissolve.
What happens to gravitational force if one object's mass increases while the distance stays the same?
Gravitational force increases.
Which planet takes longer to rotate once than to complete one revolution around the Sun?
Venus.
What is cosmic microwave background radiation (CMB)?
Radiation left over from the early universe.
As the wavelength of electromagnetic radiation increases, what happens to its frequency?
The frequency decreases.
Scientists perform an experiment three times and calculate the average results. What is the main benefit?
It makes the results more reliable.
What is the difference between a light-year and an astronomical unit (AU)?
A light-year is the distance light travels in one year; an AU is Earth's average distance from the Sun.
As a planet's distance from the Sun increases, what generally happens to its period of revolution?
It increases; planets farther from the Sun generally take longer to orbit.
Which two elements formed in the greatest amounts during Big Bang nucleosynthesis?
Hydrogen and helium.
Arrange these types of radiation from lowest to highest frequency: ultraviolet, infrared, microwaves, visible light.
Microwaves → Infrared → Visible light → Ultraviolet.
How is a scientific theory different from a scientific law?
A scientific theory explains natural phenomena, while a scientific law describes observed patterns or relationships.
Arrange these structures from smallest to largest: galaxy, solar system, planet, star, universe.
Planet → Star → Solar System → Galaxy → Universe.
Using the Solar System Objects Data Table, which has the most elliptical (stretched) orbit: Mercury, Pallas, Pluto, or Eris?
Eris.
What does redshift in the light from a distant galaxy tell astronomers?
The galaxy is moving away from us; cosmological redshift supports the expansion of the universe.
Two electromagnetic waves travel through a vacuum. Wave A has a shorter wavelength than Wave B. Which wave has more energy and why?
Wave A, because a shorter wavelength means a higher frequency and greater energy per photon.