Brightness of Planets
Depends on
– 1) Distance from earth (brighter when closer)
– 2) Albedo (ability to reflect light)
More albedo = more brightness
– 3) Size of planet (bigger is brighter)
Jupiter is far, but bright because it’s huge
Mass: amount of matter
– Not the same as weight
– Mass same in space & on earth, but weight
changes
Weightless in space
Weight has to do with pull of gravity on object
Planet’s size & mass determine surface
gravity (downward pull on objects)
– Student weighs 2.53 times more on Jupiter
If I weigh 50 kg on earth, how
much do I weigh on Jupiter?
The surface gravity is 2.53 times on
Jupiter
My weight x surface gravity = new weight on Jupiter
50 kg x 2.53
=
126.5 kg
Density – how much matter in how much
space (how tightly packed)
– Usually compared to water
Rock sinks in water (density > 1)
Wood floats in water (density < 1)
Complete the Planetary
Distances Worksheet and the
Mass/Gravity/Density worksheet