YEAR 7 PHYSICS · LESSON 2
Describing Motion
Speed and Distance-Time Graphs
Forces and Motion · 40-minute lesson · Speed = Distance ÷ Time
Lesson at a Glance
LAST
Prior learning: measurement, SI units, rulers, stopwatches, and recording measurements.
TODAY
Understand motion, calculate speed using distance and time, and interpret simple distance-time graphs.
NEXT
Forces and their effects: balanced and unbalanced forces.
Year 7 Physics · Lesson 2 · Describing Motion
2
Objectives & Success Criteria
ALL
MOST
SOME
Objective
Objective
Objective
Define motion, distance, time and speed.
Identify measurements used to describe
movement.
Calculate speed using speed = distance ÷ time.
Use correct speed units (m/s).
Interpret distance-time graphs. Explain
constant speed and stationary objects.
Success looks like
Success looks like
Success looks like
I can explain motion and identify distance and
time.
I can calculate speed using the correct formula
and units.
I can interpret distance-time graphs and
explain movement patterns.
Check for understanding: mini-whiteboards, targeted questioning, teacher scan and calculation checks.
Year 7 Physics · Lesson 2 · Describing Motion
3
Key Vocabulary
1
Motion
A change in position over time.
A moving car changes position.
2
Distance
The amount of space travelled by an object.
The car travels 50 m.
3
Time
How long an event takes.
The journey takes 20 s.
4
Speed
Distance travelled in a given time.
Speed = distance ÷ time.
5
Distance-time graph
A graph showing how distance changes over time.
A straight line shows constant speed.
Year 7 Physics · Lesson 2 · Describing Motion
4
I DO
Teacher Modelling: Worked Example
A cyclist travels 200 m in 40 seconds. Calculate the speed.
1
Speed = Distance ÷ Time
I need distance and time to calculate speed.
2
Speed = 200 ÷ 40
I divide the distance by the time taken.
3
Speed = 5 m/s
The answer needs the correct unit.
Key idea: Speed tells you how far an object moves in one second — always finish with the unit m/s.
Year 7 Physics · Lesson 2 · Describing Motion
5
WE DO
Together: Calculate the speed of a runner travelling 150 m in 30 seconds.
YOU DO
BASIC
(a) 100 m in 20 s (b) 50 m in 10 s (c) 120 m in 30 s
What information do we need?
Distance and time.
CORE
Why divide distance by time?
Because speed shows distance travelled each second.
Show working: (a) bicycle 250 m in 50 s (b) runner 400 m in 80 s (c) draw a
distance-time graph
CHALLENGE
Explain what a changing distance-time graph tells us about speed.
Year 7 Physics · Lesson 2 · Describing Motion
6
CHECK
Which statement is correct about speed?
A
Speed = distance × time
Incorrect — speed uses division.
B
Speed = distance ÷ time
Correct.
C
Speed has no units
Incorrect — speed has units such as m/s.
D
∛125 = 25
Incorrect — 5 × 5 × 5 = 125.
Reveal the answer only after everyone has voted on mini-whiteboards.
Year 7 Physics · Lesson 2 · Describing Motion
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CHALLENGE
Stretch & Depth
REAL-WORLD
A student walks 500 m in 100 seconds. Find the speed.
PROVE
Show that 600 m travelled in 120 seconds equals 5 m/s.
Year 7 Physics · Lesson 2 · Describing Motion
EXPLAIN
Why does a horizontal distance-time graph line show no movement?
EXTEND
Find two consecutive square numbers with a difference of 15. Explain
your method.
8
PLENARY
Key Takeaways
Homework
Record three examples of movement and estimate distance, time and
speed.
1
Speed measures how fast objects move.
2
Speed uses distance and time.
Resources
3
Graphs show movement patterns.
Cambridge Lower Secondary Science Learner's Book 7 (2nd Ed); toy
cars; rulers; stopwatches; graph paper; mini-whiteboards.
Next Lesson
Forces and their effects: balanced and unbalanced forces. Students
correct misconceptions in purple pen (PASA).
Year 7 Physics · Lesson 2 · Describing Motion
9