Khan Space And Science Middle School Flashcards
Ocean water is more dense when it is…
colder and more salty.
Définition “érosion”
Unsure, dégradation et transformation que les eaux et les actions atmosphériques font subir à l’écorce terrestre.
What part of the sun is or are visible during a total solar eclipse?
Only the sun’s corona is visible. It’s disk is completely covered by the moon.
A warm front occurs when…
a warm air mass moves into a cold air mass. It replaces the cold front.
At a convergent boundary, there are two oceanic plates. Plate A has a density of 2.85 g/cm3. Plate B has a density of 3.20 g/cm3. What will most likely happen as the two plates converge?
Plate B will be pushed below plate A.
What happens during a lunar eclipse?
The shadow of Earth falls on the moon. Earth blocks direct sunlight from reaching the moon.
City A is located 60 degrees north from the equator (0 degrees). City B is located 30 degrees north from the equator. Which location is likely to have the cooler climate, and why?
City A, because it receives less direct sunlight throughout the year.
Mars is visible in the night sky from Earth. Most of the time, Mars is seen moving in one direction across the sky. During certain periods, however, the planet seems to move backwards as it travel through the sky. What type of motion is this an example of?
Apparent motion.
Mars does not actually move backwards in its orbit. Instead, it appears to do so during certain periods because it orbits the sun more slowly than Earth does.
By about how many ppm (units of part per million) did CO2 levels in the atmosphere rise between the start of the Industrial Revolution (mid-1700s) and 2021?
It went from about 280 ppm to about 420 ppm, thus an augmentation of about 140 ppm.
Between 1975 and 2020, global meat production approximately tripled. One reason for this is an increase in the number of people in the world. How did the population evolve between 1975 and 2020. Can it explain fully the increase in global meat production?
Between 1975 and 2020, the world population approximately doubled, going from about 4 billion to approaching 8 billion. This does not fully explain the increase in global meat production during this time.
Give 2 facts that are evidence for the theory of plate tectonics.
Fossils of the same species are often found on different continents. This suggests that the continents were once joined together.
Some of the continents seem to fit together like puzzle pieces. The coastlines of some of the continents have complementary shapes. This suggests that the continents were once joined together.
Name two factors affecting the force of gravity between two objects?
According to Newton’s law of universal gravitation, the force of gravity between two objects depends on the masses of the objects and the distance between them.
How can humans reduce erosion along a riverbank?
By planting trees and bushes on the riverbank. Plant roots help slow or prevent soil erosion.
Removing vegetation would likely increase erosion along the riverbank.
Redirecting water into the river to increase its volume would likely increase its erosion power.
Which 2 properties define an air mass?
Humidity (dry or moist) and temperature (warm or cold).
Not its location.
Which plate movement forms trenches?
Convergence.
