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GCSE Chemistry · key term
A straight line drawn so that its direction matches a curve at the chosen point.
Used by AQA, Edexcel and OCR
Specification 4.6.1.1 · Paper 2
A straight line drawn at a chosen point on a curve that follows the curve’s direction there. Its gradient shows the rate of change at that point.
Revise: Calculating Reaction RatesTo judge the rate at one chosen time on a curved graph, draw a straight tangent that touches the curve there and follows its direction. A steeper tangent indicates a faster rate. All students should be able to draw a tangent and use its slope to compare rates.
Specification 7.5 · Paper 2
Revise: Graph InterpretationTo estimate the instantaneous rate at a chosen time, draw a tangent whose direction matches the curve at that point. Choose two well-separated, convenient points on the tangent, calculate its gradient, and attach the correct units.
A straight line that touches a curve at the point where its gradient is being estimated.
Specification CM5.2iii, C5.2b, CM5.3iii, CM6.1iii · Paper 2 (Foundation), Paper 4 (Higher)
A straight line drawn to have the same gradient as a curve at the point where it touches the curve.
Revise: Gradients as RateDraw a long straight tangent that touches the curve there and follows its direction at that point.
A straight line that touches a curve at the chosen point and follows the curve's direction there.
A straight line drawn to touch a curve at a chosen point, following the curve’s direction there.
A straight line drawn to touch a curve at a chosen point and follow the curve's direction there.
Paper 1 (Foundation), Paper 2 (Foundation), Paper 3 (Higher), Paper 4 (Higher)
A straight line drawn at a chosen point on a curve with the same gradient as the curve at that point.
Revise: Interpreting rate graphsTo find the instantaneous rate at one chosen time, draw a tangent to the curve at that point. The tangent should follow the direction of the curve locally.
A straight line drawn at a point on a curve in the same direction as the curve there.
A straight line that follows the direction of a curve at a chosen point, used to find the gradient at that point.
For a rate at one particular time, draw the tangent at that time. Higher Tier students should calculate its gradient using two well-separated points on the tangent, not two points on the curve.
For a curve, do not find the instantaneous rate using two points on the curve either side of the stated time; draw a tangent at that time and calculate its gradient.
Use two points on the tangent—not two points on the curve—to calculate an instantaneous rate.
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