I know that I use the word 'gravity' several times a day in my job, let me give you a short script:
'excuse me do you have these Boots in a bigger size please? they are a bit tight around my calf'
' yes madam we do have the next size up, but it is always better to buy knee boots that are quite snug on the leg, as the leather will stretch with wear and then gravity kicks in and the boot wrinkles at the ankle.'
When sir Newton sat under the apple tree a big apple hit him on his head splitting it open and he bled profusely thus he realized the ( gravity ) of the situation !