Science Midterm Study Guide

• ​The sun is a main sequence star

• Mass determines a stars lifespan

• The sun will release energy for 10 billion years

• People use hydrogen and helium when observing the Sun

• Nuclear fusion releases more energy than chemical combustion

• Sun's main fuel is hydrogen

• The sun has been releasing energy for 4.6 billion years

By Maya F

• ​Emission spectra helps us identify the elements in the Sun

• When 2 hydrogen fuses to helium it releases energy

• Sunspot maximum, and solar magnetic field happen every 11 years

• Bigger stars burn faster resulting is a shorter lifespan

• Elements heavier than iron only form during supernova explosions

• The smaller the stars the bigger the lifespan

• Gravity is greater at shorter distances

• In the main sequence gravity and fusion forces are equal

• The solar system formed from a nebula

• The inner planets are Terrestrial and the outer planets are Jovian

• Terrestrial are small and dense and Jovian are large and gaseous

• The closer the planet is to the Sun the faster the orbit or speed and vice versa

Also Sun and planet info

• Life didn't exist and evolve until about 3.5 billion years ago

• There was no oxygen at first but then fossils produced oxygen through photosynthesis

• The LHB happened about 3.75 to 4 billion years ago

• We know this because of radiometric dating

• Craters were destroyed on Earth because of erosion, weathering, deposition and plate tectonics

• This removed our evidence of what happened

Late Heavy Bombardment

• Uranium-238 is used for older rocks because it has a longer half-life

• Carbon-14 is used for recent rocks because it has a shorter half-life

​Radiometric Dating

• If there is more plant cover there is less erosion

• Porosity- space for water

• Permeability- ability for water to flow

Igneous rocks- form from magma/lava
Sedimentary rocks- form in layers in sediment ( fossils )
Metamorphic rocks- form from heat and pressure

Cleavage- when a rock breaks flat
Fracture- When the rock has cracks
Hardness- If it leaves a mark after you scratch it
Luster-How life reflects off their surface