There are four main classifications of galaxies

Elliptical galaxies which are featureless and spiracle.

Galaxy Picture Credits

Spiral galaxy
The Hubble Heritage Team (AURA/STScI/NASA) NASA Headquarters - Greatest Images of NASA (NASA-HQ-GRIN) -http://nix.larc.nasa.gov/info;jsessionid=1sl2so6lc9mab?id=GPN-2000-000933&orgid=12http://imgsrc.hubblesite.org/hu/db/images/hs-1999-25-a-full_tif.tif

Elliptical galaxy

NASA/ESA Hubble Space telescope - http://www.spacetelescope.org/images/potw1519a/

Barred galaxy
NASA, ESA, and The Hubble Heritage Team STScI/AURA) - http://hubblesite.org/newscent....er/archive/releases/ http://www.spacetelescope.org/images/opo0501a/ ([cdn.spacetelescope.org/archives/images/screen/opo0501a.jpg direct link])

Lenticular

NASA, ESA, and The Hubble Heritage Team (STScI/AURA) - http://www.spacetelescope.org/images/opo0624a/ (direct link) http://hubblesite.org/newscent....er/archive/releases/ (direct link)
Spiral these have arms that spiral outward


Lenticular galaxies are given the symbol S0. These galaxies consist of a bright central bulge, similar in appearance to an elliptical galaxy, surrounded by an extended, disk-like structure.

Irregular galaxies are any other galaxy

Learn all about the stomach. The stomach is a major site of digestion and is a muscular pouch.
In the video, I cover the basic anatomy of the stomach and several facts about the stomach.
The stomach has four main regions, the cardia, the fundus, the body, and the pylorus.

Picture of stomach
By DBCLS 統合TV, CC BY 4.0, https://commons.wikimedia.org/....w/index.php?curid=55

The first stage of mitosis called prophase

State of Georgia 7th Grade Math Year in Review
Topics covered this video
Adding sign numbers
Subtracting sign numbers
Dividing Decimals
Multiplying fractions
Divide mixed numbers
Convert fractions to a decimal
Convert percent to a decimal
Convert decimal to a percent

Example Problems
-3 + 9
-24 + -17
72 - -5
-93.1 ÷ 24.5
3/4 * 1 2/3
convert 2/5 to a fraction
convert 5/8 to a decimal
convert 20% to a fraction

7th Grade Math Playlist ( Entire Year)
https://www.youtube.com/playli....st?list=PLurjkZV1ykG

Learn more about Arthropods
http://www.moomoomath.com/arth....ropods-characteristi

What are the main characteristics all arthropods have? Arthropods are everywhere. They range from bees to spiders. All arthropods have several traits in common. They all have an exoskeleton, bilateral symmetry, jointed bodies, and segmented
appendages.
Keywords: Arthropods for beginners, Arthropod Definition

0:00 Introduction
0:19 Exoskeleton
0:47 Segmented Bodies
1:08 Jointed Appendages
1:51 Open Circulatory System

Arthropods
https://moomoomath.com/charact....eristics-of-arthropo

In this video, I answer the question, " What makes an insect an insect?
An insect belongs to the phylum Arthropoda and the class Insecta
Insects have an exoskeleton,wings,6 legs, and a segmented body.

Ecological pyramids
Ecological pyramids show how energy is transferred in an ecosystem.
In this video, I cover three types,
pyramid of energy
pyramid of biomass
pyramid of numbers

Moons of the planets. I review the 7 largest moons of Saturn
I review the following moons
Mimas
Enceladus
Tethys
Dione
Iapetus
Rhea
Titan
Transcript
http://www.moomoomathblog.com/....2020/07/7-largest-mo

Pictures of moons
https://en.wikipedia.org/wiki/Moons_of_Saturn

In this video, I describe the four stages of mitosis, prophase, metaphase, anaphase, and telophase.
During metaphase, the sister chromatids align in the middle of the cell.
However for this to happen a couple of things had to happen during prophase
During prophase, the chromatin condensed into x shaped chromosomes.
Each half of the x is a sister chromatin with identical copies of the DNA
In other words, a sister chromatin is 'one-half' of the duplicated chromosome.
The two sides of the x shaped chromosome is attached at the centromere.
Centromeres are the regions of DNA where the sister chromatids are most tightly connected.
During anaphase, the chromosomes line up in the middle of the cell.
The chromosomes move away from each other during the phase of mitosis called anaphase.
Finally, in telophase, the nuclear membrane reappears and the cell pinches in the middle.

What happens in the mitochondria?
In this video I would like to talk about what happens in the mitochondria.
The mitochondria is often called in school the powerhouse of the cell. It is a structure in the cell that generates ATP which is converted into energy. Think of the mitochondria as the charging station for your cell phone. Without any power your cell phone is not very helpful.

A mitochondria looks almost like a small cell inside a cell. It has ribosomes and dna. It has the ability to duplicate.
The mitochondria has two layers, an inner membrane and an outer membrane, the matrix, and the intermembrane space.

Cellular respiration requires sugar and oxygen in order to create ATP

First, the sugar in the form of glucose is converted into two pyruvates in a process called glycolysis This occurs outside the mitochondria and produces 2 ATP

The pyruvate which earlier was sugar travels into the mitochondria and more specifically the matrix.
At this location the pyruvate helps power the krebs cycle
During this process carbon dioxide is given off and NADH and FADH2 are formed and 2 molecules of ATP

Now we move to the step in which oxygen is used.Inside the inner wall are protein pumps.
NADH and FADH2 provide energy for these pumps and hydrogen ions flow back and forth through the protein pumps and generate 34 ATP.
This is called the electron transport chain.

The waste products from powering the electron transport chain protein pumps combine with oxygen to produce water molecules.
Take a journeyto the cell
https://www.youtube.com/watch?v=QS274gwv_Sc
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Take a journey into a cell and learn about the cell organelles
https://www.youtube.com/watch?v=3sgSJ44hOEg

A concave mirror curves inward in the center. In this video, I use a laser to demonstrate ray of incidence, the ray of reflection,focal point,center of curvature, and the vertex

The Equinox is the date in which the day and night are equal. The Solstice is the longest day of the year? Because the Earth is tilted at a 23.5 degrees angle and also rotates and revolves around the earth the length of the day varies though out the year
During each equinox, both hemispheres receive almost equal amounts of sunlight
12 hours of daylight and 12 hours of nighttime.
Questions answered in this video?
What are the dates of the vernal equinox and the autumn equinox?
What are the dates of the summer solstice and the winter solstice?
What is the equilux?
When is the shortest day of the year?
When is the longest day of the year?

Have you ever wondered how you catch a cold? I discuss 5 ways microorganisms spread.
These include direct contact, indirect contact, airborne, oral route, insects and pests.

Learn how to create a stem and leaf plot. A stem and leaf plot is another method for organizing data so you can see patterns.
Draw the Stem and Leaf Chart
Identify the Stem
Sort your data and divide the numbers into a stem and a leaf
Provide a key

Mountain and Valley Breezes occur when the slopes of the mountain and the valley heat up and cool off at different rates. Valley breezes occur during the day and mountain breezes occur at night.

What happens during metaphase?
In this video, I would like to talk about the stage of mitosis called metaphase.
Mitosis consists of four stages and I always remember mitosis using PMAT
For Prophase Metaphase Anaphase Telophase
During metaphase the sister chromatids align in the middle of the cell.

However for this to happen a couple of things need to happen during prophase
During prophase the chromatin condenses into x shaped chromosomes.
Each half of the x is a sister chromatid and identical copies of the DNA
The two sides of the x shaped chromosome are attached at the centromere.

During metaphase spindle fibers appear These fibers create something called the spindle apparatus.
It consists of spindle fibers, centrioles, and another fiber called aster fibers
In plants, the centrioles are missing.
These spindle apparatus move to the poles of the cell.
The spindle fibers attach to the centromeres of the sister chromatids at the kinetochore.
After the spindle fiber is attached at the kinetochore the sister chromatid is pulled along the spindle apparatus and eventually end up in the middle of the cell.

Metaphase is the shortest stage of mitosis but is important because it helps ensure that new cells have correct copies of the chromosomes.
Take a journey to the cell
https://www.youtube.com/watch?v=QS274gwv_Sc

Learn the basics of Lichen and Moss. In many places on Earth, you will find Lichen and Moss living beside each other. Although they may look similar they are very different. Lichen are actually a symbiotic relationship between fungi and cyanobacteria. Moss are nonvascular plants.

Learn how to easily memorize the global winds.
Polar easterlies, westerlies, and trade winds.
Memorize the location, name, and direction that that flow.
Includes the tropical easterlies.
Use the mnemonic device Every wind together in order to help remember the global winds.

This video on Global Winds may help
https://www.youtube.com/watch?v=oCdqGkn-B1E

When telling time there are different ways you can tell someone what time it is.
For example, when the small hand is on the three and the large hand is on the five could be called 3:05 o five past three.
In this video, I go over common phrases used when telling time.

Diffraction is the bending of light as it passes around the edge of an object or through a slit.
Refraction is the bending of a wave when it enters a medium where its speed is different.
When a wave passes through a slit it spreads out in waves as it passes through the slit.

Learn about the arctic and alpine tundra.
The tundra is a very cold and dry biome.The arctic tundra is found in North America, Asia, and Europe and circles the arctic ocean and stretches southward down to the taiga.The alpine tundra occurs at any latitude and is found at high elevations of 10,000 feet and
above.
The alpine tundra is found above the tree line and does not have any trees
Because of the high elevation, the alpine tundra has a climate and rainfall similar to the arctic tundra.

Let’s take a look at the difference between specular reflection and diffuse reflection.
Specular reflection reflects all light that arrives from a given direction at the same angle, whereas diffuse reflection reflects light in many different directions.
I also review the law of reflection and the difference between the incident ray and reflective ray.

Picture of spheres
https://en.wikipedia.org/wiki/....Specular_reflection#

Transcript
http://www.moomoomathblog.com/....2020/07/specular-and

This video is about biomes of the world. I include great video and pictures of the following biomes, Desert, Rainforest, Taiga, Deciduous Forest, Grasslands, Savana and the Tundra.

0:24 Desert Biome This tundra can be hot or cold but what it has in common is the small amount of rainfall this biome receives.

3:46 Tropical Rainforest This biome is the complete opposite of the desert because of the amount of rainfall this biome receives.It has a very large diversity of plants and animals.

7:01 Taiga The taiga is cold and contains coniferous trees.

9:42 Deciduous forest This biome contains trees that drop their leaves.

11:50 Temperate Grassland The grassland has lots of grass and very few trees.

14:06 Savanna The savanna is home to very large animals like an elephant and giraffe.

16:19 Tundra The tundra is cold and is found near the arctic circle.

MooMooMath and Science upload a new Math and Science video every day.

You may also enjoy ....
Introduction to Biomes
https://youtu.be/cXo9YczQBo4

In this video I would like to talk about physical and chemical changes. Physical changes are changes in appearance only.
A new substance is not created and new chemical bonds are .not formed or broken.
For example, take this stack of paper, and wading it into smaller pieces is a physical change.It still has the same properties as the original paper.
Cutting someone's hair is a physical change.
The hair has the same properties as the original hair.
Phase changes are physical changes.
When ice goes to solid,liquid ,then a gas and back it is a physical change.
Most mixtures are a physical change.
Mixing salt and water is a physical change because you can separate it later.
Chemical changes on the other hand create a new substance.
It involves breaking or making new chemical bonds.
between atoms.
Chemical changes leave behind clues or indicators of a chemical change.
Here are 5 indicators of a chemical change.
First if you see burning or fire it is a chemical change.
A temperature change without heating or cooling is a chemical change.
An explosion is a chemical change. They are also pretty cool.
A change in color is a chemical change.
A change in odor is a chemical change and anytime you have bubbles of fizzing you have a chemical change.
Thanks for watching physical and chemical changes,, MooMooMath and Science uploads a new Math and Science video everyday.

Updated video Physical and Chemical Changes
https://youtu.be/W5tifZPNo_Y

More on Physical and Chemical Changes
http://www.moomoomathblog.com/....2017/03/physical-and

Physical and Chemical Properties
http://www.moomoomathblog.com/....2023/01/physical-and

What is a chemical Reaction?
https://moomoomath.com/what-is....-a-chemical-reaction

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Please watch: "Study Skills Teacher's Secret Guide to your Best Grades"
https://www.youtube.com/watch?v=f3bsg8gaSbw
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For more Life Science videos and summaries see,
http://www.moomoomath.com/Midd....le-School-Science-an

Confused about Science variables? In this video, I use 5 experiments in order to help you gain an understanding of Science variables. For example, which car cooler is the coolest temperature in the summer. The different colors are your independent variable and what you are measuring which is temperature is your dependent variable. Your control variables would be same location, measuring the temperature the same way.
Does eating bananas lower your blood pressure? What would be your variables in this experiment?