Science - 'Sir, why don't you like dogs?'

Tes Editorial

What the lesson is about

Teaching terminal velocity needs a staged approach where the teacher can explain each development in the motion - a smartboard can help, and a bit of humour, writes Simon Porter.

A dog (accidentally) falling from an aeroplane at first has only the force of gravity pulling it down, so it will accelerate (slide 1). As the dog goes faster (slide 2), the force of air resistance increases but, because it is still less than the force of gravity, the forces are unbalanced so the dog continues to accelerate.

Eventually (slide 3), the force of air resistance becomes equal to the force of gravity, so the forces become balanced and the dog falls at a constant speed (called terminal velocity).

The staged approach means the teacher can go back and forth rapidly between the slides when pupils need to have a point repeated or reinforced, and slides can be printed out for them to stick in their books.

Taking it further

The same approach can be used to explain orbital motion and centripetal acceleration. A dog can be kicked horizontally off a table only a certain distance (slide 1).

A small cannon is required to fire the dog horizontally further, but the dog is still pulled down by gravity (slide 2). An even larger canon (slide 3) will fire the dog even further than expected, as the curvature of the Earth now has to be taken into account, although gravity continues to pull - and thus accelerates - the dog towards the Earth, and so on.

Where to find it

Simon's "dogs in orbit!" and "dogs falling from aeroplanes" can be downloaded free from TES Resources.

Register to continue reading for free

It only takes a moment and you'll get access to more news, plus courses, jobs and teaching resources tailored to you

Tes Editorial

Latest stories

Schools need to be ready for any blame pushed onto teachers by unhappy pupils

GCSE results day 2021: How to handle TAG unhappiness

What should a teacher do if a student blames them for not getting the GCSE grade they think they deserve this year? Tes rounds up advice for those preparing for that possibility
Grainne Hallahan 5 Aug 2021
Teacher assessed grades, TAGs, results day 2021

SQA results day 2021: how we got here

It’s been a frenetic year – with exams were cancelled and the SQA due to be replaced – so here’s a recap of events on the road to results day
Emma Seith 5 Aug 2021