How Can You Tell How Fast a River Is Moving?

What Crafty Clover says in this video

Intro

Hi there, curious minds! I'm Crafty Clover! Let's discover something amazing. How can you tell how fast a river is moving?

The Big Idea

You can find out how fast a river is moving with a leaf and a clock! Drop the leaf in at one point and time how long it drifts a measured distance. Then divide the distance by the time.

Measure a Distance

Step one: measure a distance. From a safe spot on the bank, pick a start and a finish line. Measure how far apart they are, for example 30 feet.

Time the Leaf

Step two: time the leaf. Drop a leaf or stick in at the start line, and start the timer. Stop the timer when the leaf passes the finish line.

Do the Math

Step three: do the math. Divide the distance by the time to get the speed. If the leaf goes 30 feet in 10 seconds, the speed is 3 feet per second.

A Closer Look

Let's take a closer look at measuring speed! First, measure the distance along the bank. Next, drop a leaf and let it float. Time it with a stopwatch. Then divide distance by time to get the speed. River scientists use floats and special meters in the same way.

Quick Facts

Quick facts! Many rivers flow at about walking speed, around 2 to 4 miles per hour. Scientists use floats and special meters to measure speed. Do this only from a safe spot well back from the water. Stay with a grown-up near any river.

Think Like a Scientist

Now, think like a scientist! With a grown-up in a safe place, you can drop a leaf in a slow stream. Or float one in a bathtub or a long tray. Time it over a measured distance. Then divide to find the speed. You just measured a current!

Outro

Distance divided by time gives speed. Science is amazing! Crafty Clover can be found on Amazon Books, Google Bookstore, and Apple Books. Available for purchase or download! Bye for now!