Experiments About Tides for Kids

Understanding Tides

• Tides can be confusing as they are constantly changing. Children may wonder where all the water is going when the tides are low. A great way to showcase this concept is with a simple experiment from Whyzz. Fill a pan evenly with water and show the child. Slowly tilt the pan to one side so that water flows toward one end. Explain to the child that this is what happens during tidal shifts as the pull of gravity causes a similar tilt on earth. The water is not disappearing, it is just moved to the other end of the pan. The side of the pan with less water represents the low tide beach and the side with more water is high tide. You can then tilt the pan in the other direction and show how the tides shift in either direction as the earth rotates and gravity pull changes.

Timing Tides

• Once a child understands the basic concept of tides, they can time tides on a local beach. If the shore is nearby, Science Buddies suggests taking the child to a local beach for hands-on timing of the tides. You will want to check your local newspaper to find out when high and low tides will be occurring on the beach so you can arrive at the beach at high tide. Bring a few long stakes, some measuring tape, a pencil and a sheet of paper. When you arrive at the beach place a stake at the edge of the water and write down the time the stake was placed. Every hour you will want to place a new stake at the edge of the water and measure its distance from the first stake. You can do this for a set amount of time, or until the posted time for low tide. You can then calculate how much the tides changed each hour and how much they changed in the course of your stay.

Tidal Bulge

• A tidal bulge occurs when there is more water on one side of the earth than the other. Two tidal bulges can happen at the same time when the moon is pulling tides toward itself while the Earth's rotation is pulling water outward. This results in high tides each on opposite ends of the Earth with low tides 90 degrees perpendicular to each of those high tide areas. To show a child how a tidal bulge would form, KidsGen suggests utilizing a blow-up globe or ball and a sturdy bucket that has two holes on top, opposite one another. Secure a string to the ball and then a string to each of the holes. First place the ball in the bucket of water and pull the string to one side. You will notice the ball now has more water on one side, this would be a standard tidal bulge. Next have two people pull on the strings attached to the bucket at the same time. This will cause the bucket to expand outward with two tidal bulges. Someone can rotate the ball in the center to show how the high tides and low tides would change location on the earth as it spun.

Bay of Fundy

• If a child is particularly interested in tides, you may consider giving them a little information on the Bay of Fundy, which has the most drastic tidal changes on our planet. In fact, each day over 100 billion tons of water flow through the bay. Pointing out the bay on a globe and discussing some of the reasons the tides are so drastic while showing the child a time-lapse video of the bay can add another layer to the learning experience. Youtube has a large collection of time lapse videos for viewing.