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GCSE Combined Science
Body mass index
A measure relating body mass to height, calculated as BMI=mass in kg(height in m)2\text{BMI}=\frac{\text{mass in kg}}{(\text{height in m})^2}BMI=(height in m)2.
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Boiling
The change of state from liquid to gas throughout a liquid at its boiling point.
Boiling point
The temperature at which a liquid boils and becomes a gas.
Bond energy
The energy needed to break one mole of a particular type of chemical bond, usually expressed in kJ/mol. The same magnitude of energy is released when those bonds form.
Bone marrow
Soft tissue inside bones that contains stem cells which produce new blood cells.
Braking distance
The distance a vehicle travels under the braking force, from when the brakes are applied until it stops.
Breathing rate
The number of breaths taken per minute.
Breath volume
The volume of air moved into or out of the lungs in one breath.
Bromine water
An orange solution of bromine in water that becomes colourless when it reacts with an alkene.
Buckminsterfullerene
The first fullerene to be discovered: a spherical, hollow molecule containing 60 carbon atoms, with formula C60\mathrm{C}_{60}C60.
Buffer solution
A solution that maintains a nearly constant pH during a reaction.
Bulk property
A property of a substance as a whole, such as its melting point, boiling point or electrical conductivity.
Burning splint
A thin piece of wood with a flame at one end, used to test for hydrogen gas.
Calibration curve
A graph relating a sensor’s readings to known values of the quantity being measured, allowing later readings to be interpreted.
Cancer
A disease resulting from changes in cells that lead to uncontrolled growth and division. Malignant tumour cells are cancerous.
Capillary
A very small blood vessel where substances are exchanged between blood and surrounding tissues.
Carbohydrase
An enzyme that breaks down carbohydrates into simple sugars.
Carbonate
A compound containing carbonate ions, CO32−CO_3^{2-}CO32−; some carbonates are insoluble and can form sediments.
Carbon brush
A stationary conducting contact that touches the rotating commutator, allowing current to flow between the external circuit and the coil.
Carbon capture and storage
Collecting carbon dioxide released by power generation or industry and storing it to prevent its release into the atmosphere.
Carbon cycle
The movement and recycling of carbon between organisms and the environment.
Carbon footprint
The total amount of carbon dioxide and other greenhouse gases emitted over the full life cycle of a product, service or event.
Carbon monoxide
A poisonous gas that combines with haemoglobin in the blood, reducing its ability to carry oxygen. It is colourless and odourless.
Carbon nanotube
A cylindrical fullerene with a very high length-to-diameter ratio.
Carbon offsetting
Compensating for emissions through activities intended to remove greenhouse gases or reduce emissions elsewhere, such as funding reforestation.
Carbon reduction
The removal of oxygen from a metal oxide by reaction with carbon, producing the metal.
Carcinogen
A substance or agent that can cause cancer.
Cardiac output
The volume of blood pumped out of the left ventricle per unit time, calculated as stroke volume multiplied by heart rate.
Cardiovascular disease
A disease affecting the heart or blood vessels.
Carrier
A person who has one copy of a recessive allele causing a disorder, does not have that disorder, but can pass the allele to their offspring.
1,180 key terms
