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The Solar System
The Solar System
The Sun & the Planets
The Sun lies at the centre of the Solar System. The Sun is a star that makes up over 99% of the mass of the solar system. The Sun produces light that allows us to see all the other objects in the Solar System. Our sun looks massive compared to other stars as it is very close to the Earth, while other stars are far far away.
The 8 planets in our Solar System in ascending order of the distance from the Sun are:
Satellites
Satellites stay in orbit around planets due to the force of gravity. Satellites can be seen because they reflect light. There are two types of satellite:
Moons are an example of natural satellites.
Artificial satellites are man-made and can orbit any object in space. Most orbit the Earth.
The International Space Station (ISS)
GPS – for navigation
Weather satellites
Telescopes for observing the Earth and deep space
Spy / Military satellites
Asteroids & Comets
Asteroids and comets also orbit the sun but they are not planets.
An asteroid is a small rocky object which orbits the Sun.
Planets and large moons can pull an asteroid or comet out of the suns orbit causing it crash onto the surface causing an impact crater.
The Earth
The Earth is a rocky planet that rotates in a near circular orbit around the Sun. It is held in orbit by the force of Gravity.
It rotates on its axis, which is a line through the north and south poles. The axis is tilted at an angle of approximately 23.4° from the vertical. The Earth completes one full rotation (revolution) in approximately 24 hours (1 day)
This rotation creates the apparent daily motion of the Sun rising (in the East) and setting (in the West). Rotation of the Earth on its axis is therefore responsible for the periodic cycle of day and night
Day and Night
The Earth's rotation around its axis creates day and night
Day is experienced by the half of the Earth's surface that is facing the Sun
Night is the other half of the Earth's surface, facing away from the Sun
The Earth’s Orbit and Seasons
The Earth orbits the Sun once in approximately 365 days. This is 1 year. The combination of the orbiting of the Earth around the Sun and the Earth's tilt creates the seasons.
Solar Eclipse
This takes place when the moon comes between the Sun and the Earth.
The moon then casts a shadow on the surface on the Earth.
Anyone standing in the shadow of the moon can experience sunlight during the day and then total darkness for a few minutes.
The Formation of the Universe
The universe began around 14 billion years ago as a result of a rapid expansion called the Big Bang.
From this, all mater in the universe was created.
The Universe is made up of billions of different galaxies.
Galaxies are made up of billions of stars.
The Sun is one of billions of stars in our galaxy called the Milky Way.
Other stars in the Milky Way galaxy are much further away from Earth than the Sun is.
Digestion & Enzymes
Digestion & Enzymes
The Digestive System
Food is physically digested by chewing food in the mouth and chemically by special chemicals called enzymes in the digestive system.
Large food molecules are broken down into smaller food molecules so that they can be absorbed into the blood at the small intestine.
Once all the useful nutrients and energy have been absorbed by the body, waste is egested (removed) at the anus below the rectum - pooing!
Enzymes
Enzymes are Biological Catalysts that are produced by parts of your digestive system to help chemically digest food. Enzymes speed up the breakdown of food into smaller molecules. They are very specific. They have a specific shaped Active Site that only ‘fits’ a particular substance.
Three main enzymes:
· Lipase - break Lipids (fats) down into Fatty Acids and Glycerol
· Protease - break Proteins down into Amino Acids
· Amylase breaks Starch down into Glucose
Starch is a Carbohydrate and Amylase is a Carbohydrase Enzyme.
Enzymes like specific conditions. A particular type of Protease Enzyme only works well in the Stomach as it has a pH 1 due to the Stomach Acid. Other enzymes would not function here.
The Ileum (Small Intestine)
The Ileum (small intestine) is a very long tube. On the inside of its surface are lots of finger like Villi.
Each Villus has a good supply of blood vessels to allow small digested food molecules to be absorbed into the blood.
The very long Ileum combined with the billions of villi produce a very large surface, along with the good blood supply help food molecules to be easily and quickly absorbed into the blood so that the nutrients in the food get transported around the body cells.
Revision Notes - Elements, Compounds & Mixtures
Revision Notes - Elements, Compounds & Mixtures
All substances are made from Atoms.
Atoms are made from 3 sub-atomic particles:
· Protons
· Neutrons
· Electrons
It is easier to sometimes show an atom a circle.
The Periodic Table
Most substances are compounds as there are only just over 100 Elements, listed on the Periodic Table. Each element has its own symbol on the table and position.
Elements have their own unique symbol on the Periodic Table:
The most reactive elements in Group 1 & 2 are at the top while the most reactive elements in 6 & 7 are near the bottom.
The Periodic Table is arranged in Groups and into metals and non-metals. Most elements are Metals (Blue) and some are Non-metals (Yellow)
Groups
The table has Groups from 1-0 going from top to bottom and Periods 1-7 going across.
Elements in the same groups have similar chemical properties – they behave and react in similar ways.
Some groups have their own names:
Group 1 – Alkali Metals eg Li and K
Group 2 – Alkali Earth Metals eg Mg and Ca
Group 7 – Halogens eg F and Cl
Group 0 – Noble Gases eg He and Ar
Periods
These are the rows in the table. H is the only element in Period 1.
While Na is the first element in Period 3, all the way across to Ar.
Revision Notes - Printable Version
Revision Notes - Printable Version
Year 10 Science Assessment 1 - Xmas Revision Notes New.pdfPage updated
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