Sun and Earth Unit

5-ESS1-1, 5-ESS1-2

Light

What is light?

Light is a type of energy.

• The energy for almost all living things on earth comes from light from the sun.
• Plants use the light to make food and grow, animals eat those plants and then other animals eat those animals.

Light travels in Energy Waves

• Different wavelengths have different amounts of energy
• We can only see some wavelengths (visible light)

​

Image Credit

Speed of light

• Light is FAST. It is the fastest thing in the universe.
• 186,000 miles per second.

​

Light Year

• Since light always moves at the same speed, we can use it to measure very long distances.
• 1 Light Year = the distance light travels in a year

Light Lets Us see the past

• We see things when the light they emit or the light that reflects off of them hits our eyes.
• It takes a little over 8 minutes for sunlight to reach earth, so we are seeing light that left the sun 8 minutes ago.
• Icarus, a star, is so far away that the light we see from it has been traveling about 9 billion years.

Graphs

Why use tables and Graphs?

• Tables and graphs help us organize organize information.
• Seeing information on a graph makes it easier to see patterns or trends.

Line Graphs

A good way for us to see a continuous change.

Bar Graphs

Compare similar data.

Pie Graph

Shows parts of a whole or percentages

Parts of a Graph

When you make a graph, what are things you need to remember to include? Brainstorm all the things you think you need.

Parts of a Graph

• Title
• Both axes labeled
• Unit of measurement for both
• It makes a huge difference if you’re measuring in number of cheeseburgers or degrees fahrenheit!
• Consistent scale for each axes
• You have to go up by the same amount between each line in order to see the trends in the data

​

Day and Night

Earth’s Movements

Rotation-

Picture an imaginary line running through from the North Pole to the South Pole. This is Earth’s axis and the earth rotates, or spins, around it.

Revolution -

Earth’s movement in an orbit around the sun.

Image Credit

Day and Night

• It takes 24 hours for Earth to rotate once around its axis.
• It seems like the sun rises in the east and sets in the west. Really, the sun stays still.
• Day is when our part of the Earth has rotated so that we can see the sun. Night is when it has rotated away from the sun.

Earth’s rotation causes the cycle of day and night.

Day Length

As you learned in your graphing activity, in many places on Earth, the length of day changes with the seasons.

​

At the equator, day and night are always the same, 12 hours each.

​

The farther you get from the equator, the more of a change there is in day length.

Seasons

It’s not Distance

• Earth is actually physically closer to the sun in December than in June, so distance can’t cause the seasons.

Earth’s Movement

• We already know Earth rotates around its axis. That axis is tilted 23.5°.
• That means as Earth revolves around the sun, one pole points more directly towards the sun sometimes and away from the sun other times.
• Remember when you shined your flashlight at an angle? The light was less intense than when you shined it straight at the paper.
• Less intense light means less heat.
• The tilt causes seasons.

Seasons (Northern Hemisphere)

• In June, the North Pole is pointed more directly at the sun, so the Northern Hemisphere is in summer. Days are long.
• In September, the North Pole is neither pointed towards or away from the sun. Days and nights are about the same length. We have fall.

Seasons (Northern Hemisphere) Cont’d

• In December, the North Pole is pointed away from the sun, so the Northern Hemisphere is in winter. Days are short.

​

• In March, the North Pole is neither pointed towards or away from the sun. Days and nights are about the same length. We have spring.

Constellations

Constellation Backgrougnd

Star - a ball of very hot gas that generates energy in the form of light.

​

Constellation - a group of stars that appear close together from Earth. They were given names and stories by ancient people.

Appearance of Constellations

• Stars in constellations seem close together, but can actually be thousands of light years apart from each other.
• The patterns of the constellations don’t change, but they do appear to move around the sky.
• Appear to move as the Earth rotates on its axis.
• Appear to move seasonally as the Earth revolves around the sun.
• Since the patterns stay the same, they can be used for navigation.

Polaris

• The axis around which the Earth rotates, is in line with the star Polaris.
• Known as the North Star, because it always appears straight North.
• Does not appear to move like other stars.
• The “tail” of Ursa Minor (Little Bear), otherwise known as the Little Dipper

Image Credit