DENVER (KDVR) – Friday the 13th has arrived, and the superstitious among us may be feeling a little nervous or worried. If that’s the case, perhaps these people can take comfort in the fact that they aren’t alone — and that plenty of their fellow-minded friends are attempting to ward off bad vibes with superstitions of their own. Check out five of these popular practices below, as well as the historical reasonings for these beliefs.

  • Find a four-leaf clover

According to Better Homes & Gardens, Celtic priests (called Druids) carried three-leaf clovers in the early days of Ireland because they believed the shamrocks helped them see evil spirits. The four-leaf variety were Celtic charms used for magical protection. In addition, children in the Middle Ages believed they could help them see fairies.

Here are five things to know about four-leaf clovers:

  1. Four-leaf clovers are considered rare because there are no clover plants that naturally produce four leaves.
  2. There are around 10,000 three-leaf clovers for each four-leaf clover
  3. If you find a four-leaf clover, you might find more than one. If a clover plant produces one, it’s more likely to produce another
  4. Legend has it that if you give someone else a four-leaf clover, it will double your good luck
  5. If a clover has a fourth leaf, it might be smaller or a different shade of green than the other leaves
  • Find a penny face up

Have you heard of the saying, “Find a penny and pick it up, all day long you’ll have good luck?” Well, make sure it’s face up, then tuck it in your shoe, according to superstition. But why do some consider finding a penny lucky?

“In ancient times, people often thought that metals were gifts from the gods. They thought that metal would bring protection from evil, and started believing that the finding of metal would bring good luck,” according to a post from the Northeast Regional Library in Corinth, Mississippi. “Besides this belief influencing the modern-day superstition of finding a lucky penny, pennies have also been seen as lucky because they increase wealth, and because wealth is a symbol of power. Some also believe that if you find a penny, more money is coming your way.”

  • Knock on wood

Some believe that if you say something positive and then follow it by knocking on wood, it’ll bring good luck. “I’ve never broken a bone in my life,” someone might say, before following it up by knocking on a piece of wooden furniture and saying, “knock on wood.”

While the actual origin of the phrase is different in many cultures, Google researchers said it likely links to a Celtic belief. “Spirits good and bad resided in trees who could be either called upon for protection or chased away by knocking on their home, and others, particularly Christians, [linked] the practice to the magical power of the wooden Crucifix,” Google arts and culture researchers explained.

  • Avoid cracks in the sidewalk

Those feeling superstitious on Friday the 13th will likely be avoiding cracks in the sidewalk, too. “The basic idea was that cracks were not something to trifle with because danger lurked in these empty spaces,” according to an article published at How Stuff Works. “Cracks in sidewalks, floors and soil, as well as in walls, signaled gaps in the boundaries between the earthly realm and the metaphysical realm. Interact with these chasms, no matter how narrow, and it could bring misfortune to you or your family.”

  • Cross your fingers

Legend has it that if you cross your fingers when you want something good to happen, it will bring you good luck. The same can be said for crossing your fingers for someone else. For instance, if a friend or family member tells you they have a job interview, you can tell them you’ll cross your fingers to bring them good luck.

While the exact origin is unknown, it is believed that early Christians would cross their fingers in unity with the cross to implore God’s protection from evil and evil spirits. The next Friday the 13th occurs in October. Good luck out there!