The force of attraction increases as an electron and a proton approach each other. And it varies inversely as the square of the distance between the particles. The electron and the proton have a negative electrostatic charge and a positive electrostatic charge respectively. Each charge-and the force associated with that unit of charge-is constant-and equal.
There are pools/baths dating as far back as the Ancient Greeks and Ancient Egypt however I believe there would have been something far more prehistoric than this (albeit far less advanced). The first heated swimming pool was built by Gaius Maecenas of Rome in the first century BC. Gaius Maecenas was a rich Roman lord. The great bath at the site of Mohenjo-Daro was most likely dug during the 3rd millennium BC. This pool is 12 by 7 meters, is lined with bricks and was covered with a tar-based sealant.
Swimming Pool Opening Average Costs. 1  Hiring a professional swimming pool service to open your pool for the summer might cost $200 - $300. 2  Taking the DIY approach, youâll still have to pay for a test kit ($20 - $50) and pool chemicals.