Comment by Thlom

One meter is about one long step for an adult. To approximate the length of a field, you just walk along it with big steps and count. It will not be correct, but pretty close. A cm is a little bit smaller than the width of your index finger. It's all bout what you are used to. Metric doesn't "fly over people's head" where metric is the standard way to measure things, but inches, feet, gallons, pounds, miles fly over our head because we are not used to it so don't have any frame of reference.