Upper Grades Math & Science Support
M. Mackenzie - Harbor View Elementary - NMUSD - CA

Be a Viking, explore your universe with respect and an open mind.

Study Guide for 5th graders
Go to the 4th grade page to review material you should know.

Correct answers to the question released by the Department of Education

EARTH SCIENCES ;   The Solar System

A few important words to know about astronomy.
( I mainly used WIKIPEDIA as reference.   www.wikipedia.org)

Astronomy :the study of celestial objects and phenomena which take place beyond outside Earth’s atmosphere.

Cosmos / Universe:   Later you will learn that there is a difference in meaning between the two terms but for the moment you can consider them as meaning the same.    The universe is all that exists, both known and unknown, from galaxies to atoms.   Observable universe is all that humanity can observe.

Galaxy :   a system of stars, gas, dust, plasma which are bound by gravitational forces and orbit around a center of gravity.   A galaxy can contain up to one trillion (10 to the 17th power, 17 zeros) of stars of which our sun is just an example. Galaxies contain hundred of solar systems, star clusters and nebulae and astronomers consider that there are billions of galaxies in the observable universe.   Our galaxy is the Milky Way, often written just as Galaxy with capitalized G.

Stars :   a massive body o plasma (ionized gas) outer space that is currently producing or has produced energy through nuclear fusion and which emits light because of the intense heat.   Most stars are about 1 to 10 billion years old. ( it is commonly accepted by the scientific community that Earth is about 4.5 billion years old).   Some stars are 1000 times as big as our Sun which is a yellow star about 1,392 million km (860,000 miles).   It is about 4.6 million years old, which is about half its sequence evolution, and it will later become a red giant and then a white dwarf.

Planets :   A planet is generally a large celestial object in orbit around a star and that is not a star itself (so planets do not emit light but they can reflect it).

Satellite :  any object that orbits another object (which is known as its primary). All masses that are part of the solar system including the Earth ,   are satellites either of the Sun, or satellites of those objects, such as the Moon.   You have natural satellites and artificial ones.   Our Moon is a natural satellite.

Asteroids :   small solid objects orbiting the Sun.   An example of asteroid are the planetoids (small planets).   The vast majority of asteroids are concentrated in the asteroid belt between Mars and Jupiter. This belt separates our planets into two separate groups. The four inner or terrestrial planets are characterized by their dense,rocky composition, lack of primary atmospheres, and few or no moons or ring systems. These planets are Mercury, Venus, Earth, and Mars. They other planets are called the outer planets (there are 5 of them)

Comets :   small bodies made of rocks, gas, dusty, and ice which   orbits the Sun and (at least occasionally) exhibits a coma (or atmosphere) and /or tail.

Rotation / Revolution.   Earth rotates around its axis but revolves around the Sun.   Rotation gives us the days and the nights while the revolution around the Sun gives us the seasons.

Meteorites:   usually very small (luckily) celestial bodies (many from comets) which fall of Earth.   About 2,000 pounds fall on Earth each day.

I hope you have read the above definitions as they will give you a good idea of the order of things in the universe.

The universe contains billions of galaxies.   Each of these galaxies contains in turn contain trillions of stars.   Some of these stars form systems with planets and other astronomical objects which revolve around them.
Our solar system formed around our Sun (the only body in our system which emits light) is composed of nine main planets (for the moment), some with some satellites (our Moon for example is one of 158 known moons), numerous asteroids, and small celestial bodies.   Planets revolve around the Sun at different speeds, the closer ones making a revolution faster that the outer ones.
Our solar system is located on the edge of our galaxy which is called the Milky Way.
Because our solar system is so vast, imagine the universe, scientists use a different measurement system; the Astronomical Unit (AU) which is the average distance between the Sun and Earth (150,000,000 km, 93,000,000 miles).
The Sun is the biggest body in our solar system, followed by Jupiter and Saturn.   Pluto, the farthest planet from the Sun is also the smallest and it takes it about 248 years to make one revolution around it (it takes us about 356 days, a year).   The Sun is made mainly of hydrogen (74%) and helium ( 25%).   The Sun gets its energy by the nuclear fusion of hydrogen nuclei into helium.   The Sun represents about 99% of our solar system’s mass and without it there we would be no life on earth as we know it.   There would be no photosynthesis which could be considered to be one of the fundamental building block for life on Earth.

The order of the planets starting from the Sun is:

Mercury      Venus      Earth       Mars      Jupiter      Saturn      Uranus     Neptune     Pluto

My             Very            Educated    Mother    Just      Sent        Us            Nine           Pizzas

Planets and other celestial bodies revolve around the Sun and this is made possible by the force of gravity tendency of bodies to accelerate towards each other) that all celestial bodies exert on each other.   Gravity is also the force which allowed planets to be formed.   Without it matter could not have coalesced in to large objects.

Some relationships between Sun, Earth and Moon.

Solar eclipse:   this occurs when the Moon is between the Sun and Earth and intercepts some of the light thus creating a shadow on Earth. (I will be putting a diagram soon).

Lunar eclipse takes place when the Earth is between the Sun and the Moon and it intercepts some or all of the light thus creating a shadow on the Moon which often is reddish.

Length of shadows:   while Earth revolves around the Sun, it orbits at a different angle.   The Sun has a greater altitude (goes higher in the sky) during our summer thus creating shorter shadows compared to our winter month when the shadows are shorter (also the days).

Death of a myth.   Our summers are warmer not because it is closer to the Sun but because the North Pole, and the northern hemisphere faces towards the Sun due to Earth’s tilted axis thus receiving more light radiation.   Seasons are reversed in the southern hemisphere.

MATTER AND THE PERIODIC TABLE

We started with the question:   What is matter?   and we gave various definitions.

Matter is anything that has a mass and a volume.

Matter is anything that is not energy.

Matter is made of one or more elements.  

Matter can be liquid, solid or a gas.

An atom ( means ‘indivisible’ in Greek) is the smallest particle of a chemical element that retains its chemical properties.   Each element is made of only one kind of atom (only one atomic number) An atom is divisible as we saw in class but it no longer has the chemical properties of that element.

When atoms combine they form molecules.   Water is not an element nor an atom but is made of 2 hydrogen atoms and one oxygen atom.   H2O

At this level of study we assume that there are only 3 subatomic particles which form an atom.   At the center there what we call the atomic nucleus which contains the protons (positive charge) and the neutrons ( no electric charge).   Around the nucleus and at different energy levels are the electrons (negative charge).   These electrons form a cloud around the nucleus as they jump from one energy level to another. We saw that the first level can contain only 2 electrons, the 2nd a maximum of 8 and the third18. There are more than just 3 energy level but this is good for now.

Protons and neutrons make up most of an atom's mass;  a proton’s mass is 2000 times bigger than an electron’s.

Elements are identified by their atomic number which is the number of protons in an atom of a given element.   Usually atoms have the same number of electrons and of electrons.  

Oxygen’s atomic number is 8 thus it has eight protons ( and usually 8 electrons).   Carbon has 6 protons and its atomic number is 6 ( and 6 electrons).

picture                                                                                     picture

Periodic Table:

The table is a tabular method of displaying the chemical elements.   It was first devised by the Russian Mendelev who wanted to illustrate the properties of elements. The elements are listed in order of increasing atomic number (number of protons).   The table is also divided into 7 periods (horizontal rows).   Elements in each period have electrons at the same energy levels.   The table is also organized by vertical columns (groups or family) )which group elements with similar properties because they have the same electron configuration. As an example of these similar properties remember what we called the last group (18); the Noble Gases which have all their energy level saturated.

The last column to the right groups all the Noble Gases (they are inert and do not react with other elements)