Satellite Orbits

Learning Objective: to calculate the orbital period of satellites in various altitude earth orbits.

There are basically 3 major types of satellite orbits, LEO, MEO and GEO.

LEO: Low Earth Orbit
These orbits include;
The International Space Station. The station flies at an average altitude of 248 miles (400 kilometers) above Earth. It circles the globe every 90 minutes at a speed of about 17,500 mph (28,000 kph).
ISS

Using the formulas T = [r^3 / GMe]^1/2 and c= 2 pi* r, use the orbital altitude to confirm the period of the orbit and the orbital speed.

The “A” Train: atmospheric satellites in a sun synchronous orbit.

Chemistry: Representative elements worksheet

Assignment: Identify one element from each of the following categories. Identify each element’s position in the S-P periodic table and write in the elements’ symbol (example: H for Hydrogen).

pdf copy of this worksheet:  Representative element wksht

Symbol / Element Name Categories:
Alkali Metal
Alkali Earth metal
Metal
Semi-metal (metalloid)
Non-metal
Halogen
Noble gas

s-p_table

Watch the element film at http://ed.ted.com/periodic-videos . Next, fill in the table using information from the video and from http://webelements.com/ . More information is available at: http://education.jlab.org/itselemental/

Kepler’s Laws

Here is all you need to know about Kepler’s Laws.

There are 3 laws.
1] Planets move around the sun in elliptical orbits, not circular orbits.

2] Planets sweep out equal areas in equal time.

3] The ratio of the periods of two orbiting objects can be used to predict the ratio of their orbital radii.

formally: (T1/T2)^2 =(r1/r2)^3

Watch this video to learn about Johannes Kepler’s life (history quiz on Friday).

 

Here’s a really dumb but cute video:

Chemistry Unit 1 Test

Chemistry Unit 1Test

Chemistry Unit 1 Test

This test is the Unit 1 Common Assessment

Topics covered:

Models of the atom (Bohr, Rutherford)

Electronic structure of the atom, atomic emission spectra (flame test spectroscopy / gas discharge tube spectra)

The nucleus: neutrons, protons

Isotopes

Nuclear Chemistry: Why nuclei decay, decay modes – alpha, beta, gamma, half lives

Radioactivity: Half Lives

Definition: The Half Life of a radio active material is defined as te length of time it takes for one half the sample to undergo radioactive decay.This means that after one half life only half the origonal radioactive isotope remains. The other half of the material has decayed into other isotopes or other elements (depending on the type of decay).

The half life of radioactive isotopes is determined experimentally using a Geiger Counter.

Principle of operation of a Geiger Counter

Chemistry Unit 1 Practice Quiz

Study this quiz open book, open notes.
Please explore these questions thoroughly until you understand them fully!

Chemistry Unit 1 Practice Test

Chemistry Unit 1 Practice Test

This practice test is preparation for the Unit 1 Common Assessment

Topics covered:

Models of the atom (Bohr, Rutherford)

Electronic structure of the atom, atomic emission spectra (flame test spectroscopy / gas discharge tube spectra)

The nucleus: neutrons, protons

Isotopes

Nuclear Chemistry: Why nuclei decay, decay modes – alpha, beta, gamma, half lives

Newton’s Law of Gravitation

Standards:

PH1 m. * Students know how to solve problems involving the forces between two electric charges at a distance (Coulomb’s law) or the forces between two masses at a distance (universal gravitation).

PH1 e. Students know the relationship between the universal law of gravitation and the effect of gravity on an object at the surface of Earth.

Lesson Objective: To be understand the ideas of “Action at a Distance”, the 1/r squared law, and to be able to calculate the gravitational force between two massive objects.

Newton knew that if one object pushes on another or if there was a rope between 2 objects and one pulled the other, the object would experience an acceleration.

Newton was fascinated that the earth could pull on objects without any direct connection. He called this effect “Action at a Distance”.

Newton believed that objects had some internal essence, related to their mass that somehow spread out through space and got weaker as objects were moved farther from each other. He checked his idea by considering the orbital radii and speeds of the moons of Jupiter as compared with the Earth’s moon. This all made sense.

First understand how the surface of a sphere grows as the radius increases:

Sphere-math

Draw this diagram in your notebooks and identify (label)
a] the circumference of the circle
b] the area of the circle
c] the surface area of the sphere
d] the volume of the sphere

Now consider that the gravitational essence of a mass at the center of the sphere spreads out evenly to reach the surface of a sphere 1 meter in radius.

What happens if the radius of the sphere increases to 2 meters? (discuss)

From this Newton realized that the effect of gravity must get smaller by a factor of 1/r^2.

Now let’s use Newton’s 2nd Law to develop a formula for the force of gravity.

F=ma

F=mg

g (the acceleration due to gravity at the earth’s surface) must depend on the mass of the earth (M) and the radius of the earth squared. There also needs to be some constant of proportionality – Newton called this constant “G” The Universal Gravitational Constant.

F= GmM/r^2

The actual value of G remained a mystery until it was determined experimentally by Cavendish 120 years later in 1798.

G = 6.67 x 10^-11 N.m^2/kg^2