A trochaic foot (trochee) has a long syllable followed by a short syllable (LS or /U).
Tetrameter is four feet per line.
Not all of the lines in the following poem are pure trochaic tetrameter, but most are. See if you can spot the variations – they usually happen where the poet wants to change the tone suddenly.
On the day of the explosion
Shadows pointed towards the pithead:
In the sun the slagheap slept.
Down the lane came men in pitboots
Coughing oath-edged talk and pipe-smoke
Shouldering off the freshened silence.
One chased after rabbits; lost them;
Came back with a nest of lark's eggs;
Showed them; lodged them in the grasses.
So they passed in beards and moleskins
Fathers brothers nicknames laughter
Through the tall gates standing open.
At noon there came a tremor; cows
Stopped chewing for a second; sun
Scarfed as in a heat-haze dimmed.
The dead go on before us they
Are sitting in God's house in comfort
We shall see them face to face —
Plain as lettering in the chapels
It was said and for a second
Wives saw men of the explosion
Larger than in life they managed —
Gold as on a coin or walking
Somehow from the sun towards them
One showing the eggs unbroken.
Philip Larkin – The Explosion
A closer look at the feet in this poem
U = short syllable; / = long syllable; | = division between feet