Year 8 Science Revision: Microbiology and Waves

A complete set of vocabulary flashcards covering key terms and definitions from the Year 8 Science revision booklet on Microbiology and Waves.

Microbe

A microscopic organism, such as bacteria, viruses, or fungi.

Pathogen

A disease-causing microorganism.

Skin

The human body's primary physical barrier against pathogen entry and infection.

White blood cells

Cells in the human immune system that protect the body by engulfing pathogens, producing antibodies, and producing antitoxins.

Vaccine

A biological preparation containing dead, weakened, or inactive pathogens used to stimulate the immune system to produce antibodies and grant immunity against disease.

Antibiotics

Medicines discovered by Alexander Fleming that kill or inhibit the growth of harmful bacteria inside the body.

Transverse wave

A wave that oscillates up and down or left and right, perpendicular to the direction of energy transfer.

Longitudinal wave

A wave that oscillates forwards and backwards, parallel to the direction of energy transfer.

Frequency

The number of complete wave cycles or oscillations passing a point per second, measured in Hertz ($\text{Hz}$).

Pitch

The perceptual highness or lowness of a sound note, which increases as the frequency of the sound wave increases.

Amplitude

The maximum displacement of a wave from its rest position, which determines the volume or loudness of a sound wave.

Electromagnetic spectrum

The full family of transverse waves comprising radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma waves.

Speed of sound in air

$$340\,\text{m/s}$$

Speed of sound in soil

$$3200\,\text{m/s}$$

Ear canal and eardrum structure

The anatomical path through which sound waves travel to make the eardrum vibrate, which can be obstructed by wax build-up.

Human frequency hearing range

The range of sound frequencies detectable by human ears, spanning from $20\,\text{Hz}$ to $20\,000\,\text{Hz}$.

Oscilloscope sound wave traces

Visual screen displays of sound waves where trace P represents high pitch and high volume, trace Q represents low pitch and high volume, trace R represents high pitch and low volume, and trace S represents low pitch and low volume.

Decibel

The unit used to measure sound level or volume, abbreviated as $\text{dB}$.

Yeast fermentation

A biochemical reaction in which yeast breaks down sugar to produce carbon dioxide gas and ethanol, expanding dough volume.