In this episode we use for basis of our discussion the article "Experimental evidence for tipping points in social convention" by Centola et al., published in the journal Science on 08 Jun 2018.We talk about how many people and how much efforts it would take to change the social opinions. Why is the critical mass for controversial topics so high and what could you do if you don't have it? Listen and share with you friends and colleagues. Get back to us with you views on www.scicommjc.org or on Twitter @scicomm_jc. Don't forget to follow us and sign up for our newsletter!