There is a force called the Coriolis force that affects the flow or air and water in our planet. This force is responsible for the opposite directions in which storms and ocean currents rotate in the northern and southern hemispheres. This happens because as the Earth rotates, air and ocean currents also move with it, and at different latitudes these currents have different speeds due to the earth being round (someone in the equator, for example, is moving faster than someone in the poles). These currents are then deflected sideways when they move to areas of the earth that are rotating at higher or lower speeds. The force is named after the French mathematician Gaspard-Gustave de Coriolis who studied forces in rotating systems.
One of the most repeated pieces of misinformation in the internet is that the Coriolis force can affect the direction in which the water in your toilet rotates. The truth is that the distances water travels in a toilet are so small that the angle of the water rushing into the toilet and the toilet's geometry overwhelm any effects of the Coriolis force. But the effect can be detected in small volumes of water under the right conditions.
Destin from SmarterEveryDay and Dereck from Veritasium teamed up to make twin YouTube videos documenting the Coriolis effect using a kiddie pool of water. The top video was made in the city of Huntsville in Alabama, North America, and the bottom video was made in Sydney, Australia. These two dudes explain their results and the Coriolis force very well, so I will leave it up to them.
One last thing. Destin and Dereck want you to synchronize the videos to play at the same time. You can do that by clicking "start" on both videos and then briefly stopping and starting the one you clicked first to bring it in synch with the second one when the guys flash the numbers on their computers. Enjoy!