Speed and distance-time graphs
A distance-time graph is a whole journey on one picture — including the bits where nothing happened.
Part of your national curriculum
- Physics: motion and forces: Understand the speed of moving objects and the representation of journeys on distance-time graphs
Lesson overview
What you'll learn in this lesson
Understand the speed of moving objects and the representation of journeys on distance-time graphs
Key learning points
- • Calculating speed
- • Reading the gradient
- • Average versus instantaneous
This lesson at a glance
- 28 minutes
- 14 parts to scroll through
- 3 quick checks
- Marked quiz at the end
- Gentle pace: short sittings with pauses
Words to know
Scroll down — the lesson carries on below
Watch & discover
Part 1 of 14
Watch first
Speed and distance-time graphs
An English teaching video on this topic from MrE Science. Watch it, then scroll down for the lesson.
In a nutshell
Understand the speed of moving objects and the representation of journeys on distance-time graphs
Learning cycle
Part 2 of 14
Learning cycle 1 of 2
Part 1 · Calculating speed
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 3 of 14
Learn
Calculating speed
Speed = distance ÷ time. Keep units consistent: metres and seconds give m/s, kilometres and hours give km/h. A cheetah at 30 m/s covers 108 km in an hour.
Explore the idea
Part 4 of 14
Learn
Reading the gradient
On a distance-time graph the gradient is the speed. Steeper means faster; a horizontal line means stationary; a curve means the speed is changing.
Quick check
Part 5 of 14
Quick check
An object travels 150 m in 30 s. Its speed is…
Reset break
Part 6 of 14
Pause
That's sitting 1 of 2 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Quick check
Part 7 of 14
Quick check
A horizontal line on a distance-time graph means…
Learning cycle
Part 8 of 14
Learning cycle 2 of 2
Part 2 · Average versus instantaneous
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 9 of 14
Learn
Average versus instantaneous
Average speed uses the whole journey, including stops. Instantaneous speed is the gradient at a single moment, which is why a journey average is usually lower than the top speed reached.
Quick check
Part 10 of 14
Quick check
Why is average speed usually below top speed?
Challenge round
Part 11 of 14
Game · Sort it
Which of these are true?
Drag each card into the right column. Tap a card first if dragging is fiddly.
True
Not true
Challenge round
Part 12 of 14
Game · Fill the gaps
Finish the sentences
Choose the word that belongs in each gap.
On a ____ graph the gradient is the speed.
Mastery quiz
Part 13 of 14
Marked quiz
End of lesson quiz: Speed and distance-time graphs
3 questions, marked with the reasoning shown. No timer.
1. An object travels 150 m in 30 s. Its speed is…
2. A horizontal line on a distance-time graph means…
3. Why is average speed usually below top speed?
Lesson round-up
Part 14 of 14
Lesson round-up
Ready when you are
Quiz score
Not sat
Games
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Points this lesson
0
Best run
0 in a row
Luna: 0 out of 3 on the practice checks. Only if you feel up to it — one more?
Ask LunaDo the work
Your written work for this lesson
This is the part you'd do in your book at school. Pick the pieces below, write here or on paper, and photograph anything you draw or work out.
Why the school greenhouse failed
A science club grew tomato plants in the school greenhouse. In June the plants grew well: leaves were dark green and the fruit set quickly. In July the club went away for two weeks and left the greenhouse door shut. When they came back, the leaves were curled and pale and most of the fruit had dropped.
The club had a data logger inside. It showed the temperature reached 46 °C on several afternoons and the soil moisture fell close to zero. The club knew photosynthesis needs light, water and carbon dioxide, and that enzymes in a plant work best in a narrow range of temperature. Above that range the enzymes stop working properly.
The club repeated the summer with the door propped open and a water bottle drip on each pot. Temperature peaked at 31 °C and the plants survived.
Written for Good Learning Co.
Reading questions
- Name the variable the club changed the second time, and one variable they kept the same.
- Explain, using the words photosynthesis and enzymes, why the plants were damaged in July.
- Write a conclusion for the club's report, saying how far the evidence supports it.
Method and results
WritingWrite the aim, what you changed, what you measured and what you kept the same, then record your results in a table.
1 page + results table
Conclusion
WritingExplain what your results show and why, using the scientific words from the lesson. Say how you know you can trust them.
6–8 sentences
Labelled diagram
DiagramDraw the apparatus or the process in pencil, label it fully, and photograph it.
1 labelled diagram
Reading and notes
ReadingRead the lesson text again and write the key ideas in your own words.
Half a page of notes
Saved as you type.
Part 1 of 14 · Watch & discover
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Understand the speed of moving objects and the representation of journeys on distance-time graphs