Measure Earth’s Radius With Just Legos and a Friend

The Surprisingly Simple Science of Measuring Our Planet

Ever wondered how large Earth truly is? You might think calculating its radius requires complex astronomical equipment or advanced physics knowledge. Surprisingly, with a few common household items and a friend, you can perform a surprisingly accurate measurement of our planet’s circumference.

What You’ll Need

• A friend
• A smartphone (with a compass app or the ability to measure angles)
• A few Lego bricks (or any small, uniform objects)

The Method: A Lego-Assisted Geodesy Experiment

This ingenious method leverages basic trigonometry and the curvature of the Earth. The core idea is to measure the difference in the angle of the sun’s rays at two different locations separated by a known distance.

Step 1: Gather Your Materials and Find a Sunny Day

Ensure you have your friend, your phone, and your Lego bricks ready. The experiment works best on a clear, sunny day when shadows are distinct.

Step 2: Set Up Your Reference Point

Place one Lego brick on a flat surface. Use your phone to measure the angle of the sun’s shadow cast by the brick. This will be your reference angle.

Step 3: The Separation

Your friend, carrying another set of Lego bricks and their phone, travels a significant distance directly north or south of your position. The further apart you are, the more accurate the results will be. A distance of several miles is ideal.

Step 4: Measure the Second Angle

Once your friend has traveled the agreed-upon distance, they will also measure the angle of the sun’s shadow cast by their Lego brick using their phone. They will then communicate this angle back to you.

Step 5: The Calculation

With both angles and the distance between you and your friend, you can now calculate the Earth’s radius. The difference between your two measured angles corresponds to the angle at the Earth’s center subtended by the distance between you. Using the formula for circumference (Circumference = 2 * pi * radius) and the proportion (Distance / Circumference) = (Angle Difference / 360 degrees), you can solve for the radius.

Our Take: Ingenuity in Action

This experiment is a fantastic testament to how fundamental scientific principles can be applied with everyday objects. It highlights that complex measurements don’t always require specialized equipment. While not as precise as modern methods, it provides a tangible and educational way to grasp the scale of our planet and the power of observation and basic geometry. It’s a brilliant blend of playfulness and physics, proving that learning can happen anywhere, anytime, with a little creativity.