Science Autumn Test Revision

Science Autumn Test Revision

1. Forces And Movement

   • Accelerate: get faster
   • Upthrust: a force that acts upwards on objects
   • Friction: a force that acts between two surfaces rubbing against each other.
   • Air Resistance: a force that acts to slow things moving through air. Occurs from air particles hitting a surface
   • Water Resistance: a force that acts against things moving through water. Occurs from water particles hitting a surface.
     • Drag: another name for water & air resistance
   • Resultant: the force that is most prominent between unbalanced forces.
     • Unbalanced Forces: when two opposing forces are different sizes.
   • Balanced Forces: when two opposing forces have the same size and value.
   • Weight: a downwards force caused by gravity interacting with an object.

2. Energy For Movement

   • Stores Of Chemical Energy:e.g soap, sap and fuels such as petrol.
   • Energy can also come from the sun
     • plants use the sun for photosynthesis and make it into chemical energy in sap.
       • herbivores then turn that into movement energy after eating the plant.

3. Energy Stores

   • small amount of energy can be stored in weights and springs.
     • for example in an old clock falling counterweights transfer energy to a clock

4. Types Of Energy

   • Kinetic Energy & Kinetic Potential Energy
     • AKA movement energy. KPE happens at the point of movement and KE happens during movement
       • E.G at the point of getting pushed a marble has KPE and during rolling has KE
   • Gravitational Potential Energy
     • gravitational potential energy is gained from being lifted off the earth's surface the higher up the more gpe an ob ject has
       • as soon as an object begins to fall it loses it's GPE which is then converted to kinetic energy.
   • Elastic Energy & Elastic Potential Energy
     • elastic energy is made at the point an elastic material pulls back from there it becomes KPE. While an elastic material is stretched it has EPE.
   • Renewable & Non-Renewable Energy
   • Chemical Energy
     • energy from chemical reactions. such as exothermic and endothermic reaction. plants also store it in sap.

5. Formulas

   • speed= distance/time
   • moment=force x distance from pivot
   • work=force x distance moved in direction of force
   • weight= mass x gravity
   • resistance= voltage/current

6. Resistance

   • thin wires have more resistance than thick wires
     • resistance is measured in ohms

7. Voltage & Current

   • voltage is measured in volts symbol is v. not used up in a current but can be split in a parallel circuit
   • current is measured in amperes or amps symbol is I or A depending on purpose.

8. static electricity

   • when a conductor is rubbed on a insulator the conductor transfers it's electron.
     • the conductor is now positive and the insulator negative
     • all atoms are made up of protons electrons and neutrons which balance each other. Movement of the electrons make an atom positive and the electrons have an equal but negative charge.

9. DC motor effect

   • when a current flows PERPENDICULAR to a magnetic field it produces a force that moves the wire upwards
     • a dc motor uses this force using a device that switches the current after each current.

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