For instance, on the US penny, the side with Lincoln’s head is heavier, and when spun it has a higher probability to land tails up. This unequal weight distribution occurs because the design of the heads is usually more detailed than the tails. Therefore, when the coin is spun on a flat surface, it tends to land with the lighter side facing upwards. Grab a coin right now and feel it, do both sides feel the same? In many coins, one side is heavier than the other. However, if you’re going to perform the toss, don’t purposely limit the number of flips because that would be cheating! Bias in Weight Distribution In this case, whether it be heads or tails, pick the side facing up.

In other words, the fewer the flips, the more likely it will land on the same side facing up before the toss.

This is because depending on the motion of the thumb, the coin can stay up on the side it started on before it starts to flip.Īnother scenario is that the coin may look like it’s flipping but it’s actually spinning, thus also reducing the number of flips. According to researcher Persi Diaconis, when a coin is tossed by hand, there is a 51-55% chance it lands the same way up as when it was flipped. We can never truly know because each person has a different way of tossing a coin, even when following the same method. Have you ever seen a perfect coin toss? Or rather, how can we tell if a coin has flipped flawlessly?

Head or tail coin flip