Science Revision Notes PDF

**Science revision:** 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 1. **Non-living things (that have never lived) are *physical* or abiotic features in an environment.** **Living things in an environment are the biological or biotic...

**Science revision:** 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 1. **Non-living things (that have never lived) are *physical* or abiotic features in an environment.** **Living things in an environment are the biological or biotic features in an environment.** 2. **Environmental features** **Examples** ---------------------------- -------------------------------------------------------------------------------------------------------------------- Abiotic **Water, air, soil, rocks, metals, etc, as well as conditions such as rainfall, temperature, wind, light.** biotic **Organisms such as plants, animals, bacteria, and fungi, as well as organisms that once lived and are now dead.** 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. **Waves and communication:** Sound is produced when an object vibrates, creating a pressure wave. E.g. speaker - a song plays and the sound hits the air particles which hit the other ones in the 'line' until it reaches our eardrums. **How do we communicate?** All communication requires a sender, a message and a recipient. **Mechanical and electromagnetic waves:** Waves where particles are physically moving are called mechanical waves. Mechanical waves need to move through a medium to transfer energy from A to B. Waves that are made up purely of electrical and magnetic energy are called electromagnetic waves. Electromagnetic waves do not need a medium to travel. **Types of electromagnetic radiation:** **Energy transfer:** Energy transfer describes when energy is transferred from one object to another without changing form. E.g. when a bat hits a ball or when your foot kicks a soccer ball. **Energy transformation:** Energy transformation describes the change of energy from one form to another. E.g. batteries (chemical energy - electrical energy), fire (chemical energy - light and heat). **Space travel:** Radiation can travel through empty space. Electromagnetic radiation can travel through space because it does not require a medium to travel. **Types of waves:** - - **Transverse waves:** In a transverse wave, the particles move perpendicular to the direction of the wave. E.g. vibrations of a guitar string, electromagnetic waves (light waves, microwaves and radio waves). Perpendicular means it forms a square corner or a cross. **Longitudinal waves:** In a longitudinal wave, the particles move parallel to the direction of the wave. E.g. sound waves, ultrasound waves. Longitudinal waves are where the particles of the medium vibrate back and forth parallel to the direction of the wave travel. **Other properties of waves:** Frequency - the number of waves that move past a single point per second, measured in Hertz (Hz). period- the time it takes for one wavelength to move past a single point. Wavelength - the distance from one crest to the next or from one trough to another. Amplitude - is a measurement of the amount of energy transferred by a wave. **Ear structures:** The ear collects sound and channels them into the ear canal, where the sound is amplified, then it travels to the eardrum which vibrates and sends signals to the cochlea which then sends it to the brain. **AM and FM radio waves:** The signal is added to a wave called the carrier wave. In AM, the amplitude is modulated (problem - easy interference). In FM the frequency is modulated (better signal - less interference). **Endocrine and nervous system:** 1. 2. 3. 4. 5. 6. 7. - - - -