Each will pray for two to three minutes each day, asking God to reveal himself to them, in a project organised by Premier Christian Radio.
The Atheist Prayer Experiment is part of Premier's faith discussion show Unbelievable.
Earlier this year its presenter Justin Brierley invited atheists to take part in the experiment.
It is based on an academic paper - Praying to Stop Being an Atheist - by Oxford philosopher Tim Mawson, which argues that, on balance, it is in the interests of atheists, who don't think it's absolutely impossible for there to be a God, to investigate the issue.
Tim said the experiment is not aiming at 'definitively proving whether God exists or not'. However, each participant 'will at least, by the end of it, have a little more evidence, one way or another, on the question'.
The experiment will close on Friday, 26 October. Tim will join Justin on air to hear the reactions of those who took part.
Justin says he has asked only that the participants commit themselves to finding a quiet, meditative space to pray for two or three minutes each day and that they remain as open-minded as possible to ways in which their prayers may be answered.
'Mawson's paper suggests that prayers should be kept as open as possible,' said Justin.
'But rather than asking God to turn water into wine, atheists taking part might try 'God, if you are out there, reveal yourself to me.'
Bob Seidensticker writes in a blog on the Patheos website about being one of the participants. He said the experiment was an interesting approach to evangelism as it focuses on the mystical rather than the intellectual. He doesn't expect to change but is willing to take part.
'I don't expect that I'll be able to be all that earnest – frankly, I don't have much expectation of anything supernatural happening or even much desire for God to exist – but I'll have a go.
'To any Christian who says that I'm not approaching this with much sincerity, you're right. As I read it, none is required – as it should be. Sincerity comes after the fact; sincerity is earned.'
He added, 'Not only do I think that I won't convert, I think that that's impossible. My hypothesis is that atheists like me are stuck in atheism once they get there.'I now have a chance to test that hypothesis.'
According to Justin, one of the participants dropped out before the experiment began – because she became a Christian.
'But we've found a replacement,' he said.
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