How high does the atmosphere go?

We were wanting to look at information that one would need, in order to calculate how long it would take for the NASA UARS satellite to reach the earth's surface once it entered the atmosphere. 

You can read more about satellites here http://www.nasa.gov/audience/forstudents/5-8/features/what-is-a-satellite-58.html

This concept was obviously "theoretically" only and was not be accurate in any way but its was project we decided to look at.

At the end of it we realised that we needed to learn more about the difference between speed, acceleration and velocity.  There were also a couple of other things that we learnt.

At first we thought that if we could get certain info such as mass, speed and distance, we could use one of the physics formulas we had learnt about to work this out.  

We had a look at this website http://www.ucar.edu/learn/1_1_2_2t.htm  How high does the atmosphere go?  It turned out that each of the websites we looked had different measurements but we used the first one as it was only a theory we were looking at.

The info on the website, states that the "thickness" of the atmosphere (the distance between the earth's surface and the "top" of the atmosphere) is not an exact measure. 

On this site they stated that the atmosphere is made up of 2 layers.  The layer that is closest to the earth is the Troposphere (7 miles. The Upper layer of the atmosphere is called the Stratosphere (29 miles).

The approximate measure of the atmosphere is therefore 36 miles. (according to this website).  We used this measurement.  

(There is also info on http://www.enchantedlearning.com/subjects/astronomy/planets/earth/ which states "The Earth's atmosphere is about 300 miles (480 km) thick, but most of the Earth's atmosphere is within 10 miles (16 km) of the Earth's surface.") *but we had used the first info for our theory - no matter.

If we used the formula:  Time = distance / velocity we considered that we could work out, theoretically, how long the satellite would take to reach the surface.  Obviously there are many factors involved, including friction (burn up), gravity, rotation of the earth, path of the satellite etc.

We get the velocity from this website:  

Time = distance / velocity

Time = 36  miles / 18000m/h   

Time = 0.002 hours

To convert this we x by 3600s (1 hour)

Time = 7.2 seconds.

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(Is this the correct way to convert to seconds ? - I think it is)

This is a very short time but it does make some sort of sence, if you consider that when we think we see a falling star, it is actually only a piece of space debris or meteor etc entering the atmosphere.  The time that a falling star takes is seconds as well!

Here is another site that again has different measurements and additional layers to the atmosphere.  http://csep10.phys.utk.edu/astr161/lect/earth/atmosphere.html.  They list the layers of the atmosphere as Trophoshere , Stratosphere, Ionosphere and Mesosphere = 550km in total.

We also used these measurements in the same formula:

Time = distance / velocity

Time = 550km / 28968.19km per hour (18000m/h)

Time =  0.019 hours

To convert this we x by 3600s (1 hour)

Time = 68 seconds

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After this we looked at the NASA website for info on the atmosphere.  Again it has different info and more layers, going upto 600km.  http://www.nasa.gov/audience/forstudents/9-12/features/912_liftoff_atm.html  This has the most info and presumably it is accurate as they have done a lot of research.

***One interesting thing we did find out BTW is that NASA are crashing this satellite intentionally!  That's something to think about.  We also learnt about orbital debris and how much there is in orbit.

EXTRACT  "Its orbit was been altered by Nasa deliberately to make it crash – but it is now coming down sooner than expected due to changed atmospheric conditions."

Read more: http://www.dailymail.co.uk/sciencetech/article-2040818/Satellite-falling-earth-1-3-200-chance-NASA-UARS-hit-person.html#ixzz1YnL4pVvX

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Next we looked at the formula

Force = mass x acceleration

We know the mass is 6 tonnes and 1 tonnes = 1000 kilograms therefore the satellite is 6000kg. This info of 6 tonnes comes from news reports and the NASA site.  Acceleration is 18000 miles per hour. (Note:  This figure of 18000 miles/hour comes for http://www.dailymail.co.uk/sciencetech/article-2040818/Satellite-falling-earth-1-3-200-chance-NASA-UARS-hit-person.html and other sites) 

So Force = 6000kg x 18000 miles per hour

Force is measured in Newtons (N) therefore

Force = 108 000 000 N ??

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Alternatively if I convert the 18000 miles per hour to km/h, I get  28968.19km per hour.  (I used this to convert miles to km  http://www.calculateme.com/Speed/MilesperHour/ToKilometersperHour.htm)

My calculation for Force would then be = 6000kg x 28968.19km per hour

Force = 173 809 140 N

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In any event both answers are extreme amounts of Force!  

Bear in mind, though that the satellite is set to burn up and break up the final force will differ.  This is theoretical only.  It would also make a difference to the answer in Newtons, if you use km/h or m/h. (As shown).  I think it is correct to use Km/h and not m/h for calculations, however in the UK the unit of measure is m/h so how does this effect Newton calculations.    As I am just learning about these formulas and force/mass/velocity etc - these are all just thoughts and I know I am only learning and can get things wrong.

Its interesting to think about things....

I want to look more at the difference between speed, acceleration and velocity.  They are both measured in m/s and km/h.... - depending on what system your country uses - what unit should you use for calculations??  As it gives different answers!  Also want to look at the difference between weight and mass.

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Read this website to learn how satellites stay in orbit...http://library.thinkquest.org/C007258/Keep_Orbit.htm

It seems they travel a distance and fall closer to the earth during that travelling (like a ball when you throw it).  Because the earth has constant curves the satellite does not actually fall into the earth.  It just has constant movement around the earths curves.  You have to read the article yourself to understand it.

Science - Physics - Force

Today we were looking at the basics of physics i.e. force, gravity, pressure, velocity, distance, time, mass, weight, pivot, moment, balanced & unbalanced forces, friction etc

I worked with my textbook:  KS3 Science  (Terry Hudson) and with  the BBC KS3 Bitesize section on forces.  I also completed the review and test sections of the BBC KS3 Bitesize and got 6/6 and 11/12 respectively.

Some of the things I learnt about are the units these are measured in and the formulas that are used to work out word problems.

Force is measured in Newtons (N).  Force is the push/pull action. Force is invisible but can be measured and you can see the effect that it has on objects.  FORMULA:  Force = mass x acceleration (Force on the earths surface  = mass x acceleration due to gravity or F=mg)

Velocity is measured in m/s.  FORMULA:  Velocity = Distance /Time (v=d/t)  I also learnt how to isolate the other parts of the formula depending on the information given in the word problem.  i.e. distance = velocity x time    and time = distance/velocity.

An example of a word sum for velocity is:  If a bullet travels 1000m in 2 seconds, what is its velocity?  To work this out is simple:  v=d/t therefore v=1000m/2s so velocity = 500m/s.  (Note the final units)

Some websites we looked at are:
http://www.schoolphysics.co.uk/age11-14/
http://www.physicsclassroom.com/
http://www.gcsescience.com/pfm.htm
http://www.middleschoolscience.com/formulas.pdf

Humor of the Day: The Goons and Spike Milligan

The Goons
were a group of popular comedians.  They consisted of Spike Milligan, Peter Sellers and Harry Secombe.

Humor was very important in those days, during and after the second world war and the great depression that followed, to lift peoples spirits and make them laugh.  Some say that laughter is the best medicine.

The humor is a bit dated for people born long after The Goons prime, but there are parts that are still funny and once you understand the terminology of that time, you can have a few laughs.

My favourite is: 



and this one

Spike Milligan

A funny one that Spike did was part of a series called Q.  This is one of the things he did:  A man walks into a café, purchases a baguette, and sits down at a table to eat...


Wedging the end in his mouth, he's startled when George Gershwin's 'Rhapsody in Blue' suddenly emanates from it. Slamming the bread down, the music stops and he flees. Closing in on the table, we see a sign, 'RESERVED', before a hammer crashes down on the snack.

Does that make any sense? No, but it's weirdly funny nonetheless. And that's probably the best way to sum up Spike Milligan's experimental sketch show.

Source:  http://www.bbc.co.uk/comedy/q/

"I TOLD YOU I WAS ILL"
There is a series on Spike Milligan after he died, called "I TOLD YOU I WAS ILL, which explored various highlights and lowlights of his life.

One of the low lights was his time in World War II, which is not specifically funny at all but more important, shows him to be a real person even though he always tried to be funny and keep up everyones spirits.

This is a poem that he wrote during this time:


Death Wish

*Bury me anywhere,
Somewhere near a tree
Some place where a horse will graze
and gallop over me.

Bury me
Somewhere near a stream,
When she floods her banks
I'll give her thanks
For reaching out to me
In my childhood scene;

But please -
don't bury me
In Golders Green.

-Spike Milligan, Italy, 1944

Source:  http://www.poetryperdiem.blogspot.com/

BUT sadly, he did not get his wish :( 

The grave of Spike Milligan in the grounds of St Thomas, Winchelsea, East Sussex. The epitaph reads "Duirt mé leat go raibh mé breoite", Irish for "I told you I was ill."

Source:  http://en.wikipedia.org/wiki/Spike_Milligan

Here is a bit more about Spike Milligan:
(From Wikipedia, the free encyclopedia)

Spike Milligan

Born - 16 April 1918(1918-04-16)  in Ahmednagar, British India
Died - 27 February 2002(2002-02-27) (aged 83) - Rye, East Sussex, England
Nationality -  Irish
Influences -  Groucho Marx,  Edward Lear, W. C. Fields, Walt Disney, Jacques Tati, Spike Jones, J. B. Morton, Influenced Peter Cook, Monty Python, Marty Feldman, Kenny Everett, Harry Hill, Spouse June Marlow (1952–60), Patricia Ridgeway (1962–78), Shelagh Sinclair (1983–2002)

Notable works and roles The Goon Show

A bit about Spike Milligan

1. He was born Terence Alan Patrick Seán "Spike" Milligan KBE (16 April 1918 – 27 February 2002). 
2. He  was a comedian, writer, musician, poet, playwright, soldier, and actor.
3. Milligan's early life was spent in India, where he was born, but the majority of his working life was spent in the United Kingdom.
4. He became an Irish citizen in 1962 after the British government declared him stateless.[1]
5. He was the co-creator, main writer and a principal cast member of The Goon Show, performing a range of roles including the popular Eccles.

•  Spike Milligan wrote and edited many books, including Puckoon and his seven-volume autobiographical account of his time serving during the Second World War, beginning with Adolf Hitler: My part in his downfall.
• He is also noted as a popular writer of comical verse, much of his poetry was written for children, including Silly Verse for Kids (1959).
• After success with the ground-breaking British radio programme, The Goon Show, Milligan translated this success to television with Q5, a surreal sketch show which is credited as a major influence on the members of Monty Python's Flying Circus.

Sundials

Have you even used a human sundial?


Have a look at this website - http://www.sunclocks.com/ - they have layout plans etc.


EXTRACT: 





SUNDIALS  come  in  a  wide  range  of  different  types,  though
by  far  one  of  the  most  popular  and  'interactive'  sundials  is
this  "SUNCLOCK",  or  HUMAN  SUNDIAL  -   which  uses  a
PERSON'S  OWN  SHADOW,  to  show  the  correct  clock  time !

'Human Sundials' possess several advantages, when compared
with pedestal-mounted dials - and they are often used in school
grounds, private gardens, parks or any similar public areas, etc,
mainly because these cannot be stolen or damaged by vandals.

They are certainly one of the most fascinating sundials for kids,
plus very popular educational sundials .

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Here are instructions on how to set up a horizontal sundial:
http://www.sundials.co.uk/setup.htm

- Find the direction of true north - use a compass
- Mark a shadow (cast by a true vertical object) at midday.
- Remember the sun is 'fast' and 'slow' at different times of the year (obit) and also differs according to the latitude and longitude of your location.

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Here are some good sundial mottos:
http://www.sundials.co.uk/mottoes.htm

Extract:

Light and shadow by turns, but love always

            Rachel Sarda

Time and Tide Wait For No Man

            Kathleen M Broadhead

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Here is are some interesting Scottish Sun Dials:  http://www.scottishsundials.co.uk/favourite%20images.htm