exploring our solar system part 2

8/3/2019 Exploring Our Solar System Part 2

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Exploring our Solar System

P2f part 2



Objectives

In this lesson we should learn:

about the distances involved in space

travel about manned and unmanned space flight

how very large distances are measured in

space



OutcomesFoundation Paper

You should now be able to.. Describe that radio signals take a long time to travelthrough the Solar System

Explain that manned spacecraft need to take food, water and oxygen

Know that unmanned spacecraft can withstandconditions that are lethal to humans State that unmanned spacecraft can send back

information on: temperature, magnetic field andradiation; gravity, atmosphere and surroundings

Higher paper Describe what a light-year is and its use in measuring

very large distances Explain the advantages and disadvantages of using

unmanned spacecraft to explore the Solar System



Who wants to go into space?



What do you think about space

travel? It isn¶t cheap

Are there too many dangers with tonnes of metal floating around above our heads?

What should happen to the InternationalSpace Station stuck in budget wrangles?

What do you think about Virgin Galactic

which announced the construction of a$200 million spaceport in 2005 to taketourists into low earth or bit?



The speed of light is the fastest speed that

could EVER be achieved.

The speed of light is 300 000 km per SECOND!!

(That·s 186 000 miles per second)

Light takes 2 seconds to reach the Earth fromthe moon

- it takes it 8 minutes to reach the Earth fromthe Sun



If you were in a spaceship that travelled at thespeed of light and you started a journey from theSun it would take:

about 3 minutes to reach Mercury,

5 minutes to reach Venus,

8 minutes to reach the Earth,51/2 hours to reach Pluto,

4 years to reach the next star,

5000 years to reach the edge of the galaxy,

50 000 years to reach the next galaxy,

500 000 years to reach the next Cluster!!



Real rockets don·t travel at the speed of light,

they travel MUCH slower.

The Apollo missions took 4 days to reach the

moon - at the speed of light it would havetaken 2 seconds!!

These rockets were travelling roughly 200 000times slower than light.

At this speed it would take 125 YEARS to getto Pluto!



How far«

Earth is 150 000 000Km away from the sun.

Light travels 300 000km each second

So light takes about 8minutes to reach Earth.

Very large distances in space are measured inlight years- the distance that light travels in 1year (9 500 000 000 000 000 Km)

The next star nearest to Earth (after the sun) iscalled Proxima Centauri and is 4.22 light yearsaway.



Calculating how long light takes«

Light travels at a speed of 300 000 000 m/s.

How long does light from the Sun take to reachEarth? (distance of Earth from the Sun is 150

million km)

Distance from earth to the sun = 150 000 000000 meters

300 000 000150 000 000 000

= 500 seconds (/60 =8.3 minutes)



Confused about weight and mass?

Have you ever heard anyonesaying that ³the scales don¶t tellthe truth about their weight´?You may be surprised to hear

that they are right!

Scales give a reading in kilograms,which are the units of mass, notthe units of weight.

WARNING: This lesson may alter your weight!

The confusion arises because mostpeople use the word µweight¶ whenscientists would use the word µmass¶.



What are mass and weight?

Mass is the amount of matter in an object and ismeasured in kilograms.

Weight is a force and is caused by the pull of gravityacting on a mass. Like other forces, weight is measured

in newtons and has both magnitude and direction.

Weight has different values depending on where theobject is in the Universe.

Mass and weight are not the same!

Mass is not a force and has the same value anywherein the Universe, including outer space.



Weight and mass on different planets



Why does weight vary?Gravity is the force that

attracts objects with masstowards each other.

The Earth has a bigger massthan the Moon and so exertsa stronger gravitational pullon the apple.

For example, an apple willhave the same mass onEarth as on the Moon, butits weight will be different.

The bigger the mass of theobject, the stronger the

force of gravity.



Weight and mass on the Moon



How do we calculate an objects weight?The weight of an object depends on its mass and the

gravitational field strength:

weight = mass x gravitational field strength

Weight is measured in newtons (N).

Mass is measured in kilograms (kg).

Gravitational field strength is measured in

newtons per kilogram (N/kg).

The gravitational field strength depends on the force of gravity.On Earth it is 10N/kg, but it varies depending on planet size.

The units for these quantities are as follows:



Calculating the weight of a car A car has a mass of 10,000kg.

weight = mass x gravitational

field strength

weight = 10,000kg x 10N/kg

weight = 100,000 N

What is the weight of the car?

(Use 10N/kg as the value of the gravitational field strength.)



Calculating the weight of an astronaut An astronaut and his equipment

have a mass of 150kg.

(Use 1.6 N/kg as the value of the gravitational field strength.)

What is the weight when he isstanding on the Moon?

weight = mass x gravitational

field strength

weight = 150 kg x 1.6 N/kg

weight = 240N



Calculating weight and mass



OutcomesFoundation Paper

You should now be able to.. Describe that radio signals take a long time to travelthrough the Solar System

Explain that manned spacecraft need to take food, water and oxygen

Know that unmanned spacecraft can withstandconditions that are lethal to humans

State that unmanned spacecraft can send backinformation on: temperature, magnetic field andradiation; gravity, atmosphere and surroundings

Higher paper

Describe what a light-year is and its use in measuringvery large distances

Explain the advantages and disadvantages of usingunmanned spacecraft to explore the Solar System



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exploring our solar system part 2

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