Higher ramp, further roll: changing the slope a car starts from

The idea

Raising the top of the ramp gives the car further to fall, so it comes off the ramp faster and rolls further across the floor, and the distance grows steadily with the height.

What you need

• A 1.0 m length of smooth dressed timber or plastic guttering as the ramp, with a starting line marked 100 mm from the top end
• A die-cast toy car with free-running wheels per group, and a second car of the same size
• Identical hardback books or 20 mm timber strips to raise the top end to 50 mm, 100 mm, 150 mm and 200 mm, measured with a ruler at the ramp's end
• A 5 m tape laid along the floor from the foot of the ramp, and removable tape or chalk to mark where each run stops
• A smooth hard floor with 5 m clear along a wall
• Modelling clay to load the second car, and a kitchen scale to weigh both cars
• Recording table: release height (mm), three roll-out distances (cm), average (cm), and the distance divided by the height

How to do it

1. Set the ramp's top end on one book so it is 50 mm above the floor, and lay the tape from the foot of the ramp along the wall.
2. Hold the car with its front wheels on the starting line and let it go without any push, so the ramp does all the work.
3. Mark where the front of the car stops and read the distance from the foot of the ramp to the nearest centimetre.
4. Run three trials at this height and average them.
5. Repeat at 100 mm, 150 mm and 200 mm, three trials each, marking and reading every run.
6. Work out the average distance divided by the height for the 100 mm runs, use it to predict the 200 mm distance, write the prediction down, and only then compare it with the 200 mm average already measured.
7. Weigh both cars, press clay onto the second until it is clearly heavier, weigh it again, and run it three times from 100 mm. Compare its average with the first car's average from the same height.
8. Plot height along the bottom and average distance up the side, draw the straight line the points suggest, and mark any point that sits below the line.

What you should see

The average roll-out rises with every increase in the release height. In the model, where the ramp keeps a fixed share of the energy and the floor takes it at a steady rate per metre, the distance is eta h / mu, a straight line through the origin, so a car averaging 2.00 m from 100 mm is predicted to go 4.00 m from 200 mm, 3.00 m from 150 mm and 1.00 m from 50 mm. Real runs depart from that line in ways the class can look for. The car also loses energy to rolling resistance on the ramp itself, a roughly fixed amount on every run whatever the height, so against a line calibrated at 100 mm the 50 mm run falls short, the higher runs can land beyond the line, and a straight line drawn through the points cuts the height axis above zero; a faster car also loses more to the air and to the bump where the ramp meets the floor, which pulls the highest points back down. Speed follows the same bookkeeping and does not grow as fast as distance: with g taken as 9.80 m/s^2, an ideal 200 mm drop gives 1.98 m/s and a 50 mm drop 0.99 m/s, so four times the height gives twice the speed but, in the model, four times the distance. In the model the heavier car covers the same distance from the same height as the light one, because extra mass adds energy and resistance in the same proportion, and the second car tests that prediction. The learner knows it worked when the average distance rises with every increase in height and the three trials at each height sit closer to one another than to the trials at the next height.

What changes

What you change

the height of the ramp's top end above the floor (mm)

What you measure

roll-out distance from the foot of the ramp (cm), averaged over three trials

What you keep the same

• the same car, released from the same starting line with no push
• the same ramp, the same floor and the same run along the wall
• the front of the car read against the same tape every time
• three trials at every height

Common misconceptions

Each of these ideas is wrong, and the activity is a chance to test it.

• A heavier car always rolls further from the same height.
• The car keeps speeding up once it is on the flat floor.
• Twice the height gives twice the speed.
• The car stops because it runs out of push rather than because the floor and its own bearings rub.

Safety card

Curriculum references

The NSW syllabus outcomes and Australian Curriculum v9 codes this activity supports. They are references, not a verified or complete curriculum alignment.

• Science and Technology K-6 Syllabus (2017), NESA. Current syllabus; NESA's timeline is 2026 plan and prepare, 2027 start teaching the 2024 syllabus. Code read from the official syllabus document on 2026-09-22.ST1-1WS-S
• Science and Technology K-6 Syllabus (2024), NESA. Implementation from 2027, so this code describes the future syllabus. Code read from the outcomes page on 2026-09-22.ST1-SCI-01ST1-PQU-01ST1-DAT-01
• Australian Curriculum v9AC9S1U03AC9S1I01AC9S1I02AC9S1I03AC9S1I04AC9S1I05

Sources

The pages the author read to write this activity.

1. www.scootle.edu.au/ec/search?accContentId=AC9S1U03
2. www.nsw.gov.au/education-and-training/nesa/curriculum/science/science-and-technology-k-6-2017
3. curriculum.nsw.edu.au/learning-areas/science/science-and-technology-k-6-2024/content/stage-1
4. primaryconnections.org.au/teaching-sequences/year-1/forces-fun
5. primaryconnections.org.au/v84-sequences/push-pull
6. hyperphysics.gsu.edu/hbase/sphinc.html
7. hyperphysics.gsu.edu/hbase/frict2.html