Science

Science

1. WAVES

   • SOUND
     • Amplitude - Height of wave, bigger amplitude = louder sound
     • Wavelength - Distance between the tops of two waves
     • Frequency - Number of waves per second, higher frequency = closer the waves are and higher the pitch
     • LOUDSPEAKERS
       • Sound waves are produced by a ll vibrating objects. They work by converting electrical energy into kinetic energy. It moves cone which makes sound waves
     • MICROPHONES
       • Vibrations in air make diaphragm vibrate and the vibrations are changed to electrical impulses. They can be sent through an oscilloscope which represents them as a graph on a screen
   • LIGHT
     • Reflection
       • When light reaches a mirror, it reflects off the surface of the mirror. Incident ray = light going towards the mirror. Reflected ray = light coming away from mirror
     • Refraction
       • Light waves change speed when the pass across the boundary between two substances with a different density such as air and glass. This causes them to change direction, an effect of refraction
     • Scattering
       • Scattering = When light meets a rough surface, each ray obeys the law of reflection. Light is reflected in all directions which is diffuse scattering. It explains why you can see a clear image of yourself in a shiny mirror but not in a dull rough wall

2. RESPIRATION

   • Aerobic Respiration
     • Process of breaking down glucose to make energy. Energy is used for growth, repair and movement. This happens in the mitochondria of the cells. GLUCOSE + OXYGEN = WATER + CARBON DIOXIDE (ENERGY)
   • Anaerobic Respiration
     • Whilst intense exercise when there's no oxygen, it takes place. GLUCOSE = LACTIC ACID. Later the Lactic Acid is broken down into C02 and H20 which is known as the oxygen debt
   • Smoking
     • Over time, the alveoli become damaged and change shape which reduces the surfaces area which minimalizes gas exchange which causes shortness of breath and fatigue
   • Asthma
     • Condition that affects the broncholes in the lungs, they become inflamed and produce mucus making it harder for the air to enter and leave the lungs . This causes shortness of breath and tightness in the chest. Inhalers are used as a treatment for asthma and they cause the broncholes to widen allowing for the air flow to return to normal
   • Adaptions of Alveoli
     • Large surface area = allows maximum of gas exchange
     • One cell thick walls = to minimise diffusion distance
     • Large blood supply = to ensure gases are transported quickly
     • Moist walls = to allow gases to dissolve