Starry Night
This cycle takes approximately 28 days to complete.
Moon cycle
This type of energy depends on how fast something is moving and how much mass it has.
Kinetic Energy
We rely on this liquid resource from rivers, lakes, and underground for drinking, farming, and sanitation.
Fresh water
This is the height of a wave from the middle line to the top.
Amplitude
This happens when light bounces off a shiny surface.
Reflection
The Northern and Southern Hemispheres experience opposite seasons because of this.
Earth's tilted axis
Holding a ball at the top of a hill stores this kind of energy.
Potential Energy
Coal, oil, and natural gas are useful for energy but take millions of years to form. That makes them this type of resource.
Nonrenewable resources
This wave feature is the distance from one crest to the next.
Wavelength
Unlike sound, light can travel through this.
Space or vacuum
This event occurs when the moon is covered by the Earth's shadow.
Lunar Eclipse
Two cars are going the same speed. The heavier one has more of this type of energy.
Moving energy or kinetic energy
Rain breaking rocks apart over time is an example of this type of Earth process.
Weathering or erosion
This is how many waves pass a point in a given amount of time.
Frequency
Light energy that is taken in by a material is doing this.
Absorption
This event happens when the moon blocks sunlight from reaching part of Earth.
Solar Eclipse
A stretched rubber band has this kind of stored energy before it snaps back.
Elastic potential energy
This type of resource, like trees and crops, can be naturally replaced over time—if we’re careful.
Renewable resources
A louder sound has a wave with a larger one of these.
You can’t hear someone scream in space because sound waves need this.
There's not air (medium) for the sound to travel through
Why don't eclipses happen monthly?
The moon's orbit is tilted.
When you drop a ball, this invisible force transfers potential energy into motion.
Gravity
If we use natural resources faster than Earth can replace them, they become this.
Depleted or limited
This type of wave converts information into 1s and 0s. It makes it easier to store and send information.
Digital wave
Digital signals are more reliable than these older, continuous types of signals.
Analog signals