# The Science of Ancient Greece

Melissa Pinkley

Ancient Greece had many well-known mathematicians, philosophers, and scientists. Therefore, many discoveries happened in this part of the world during that ancient time period.

Although most people of Ancient Greece did not even know of the One True God, He had equipped them with the ability to think and create. Euclid, a famous mathematician, first wrote the basic rules of geometry. Pythagoras, another Greek mathematician, created the Pythagorean Theorem, which states that a2 + b2 = c2. Both of these men’s works are still used today. How can such things be discovered by people who did not even know of God? Because the order that God created when He made the world can be observed by anyone. Even people who don’t know Him can discover His truth about the world around them.

Another famous inventor from the time of Ancient Greece was Archimedes. Archimedes had an incredible ability to discover how to make things happen based on the laws set by God within creation.

Give It a Try #1: The Law of Displacement

There is a famous story about Archimedes discovering that the king’s crown was made incorrectly by using the law of displacement. My children and I enjoy listening to this story as told by Jim Weiss on his Galileo and the Stargazers audio CD. What is the law of displacement? Let’s “Give It a Try” and find out.

Items Needed:

• One clear container (if you use a graduated cylinder or measuring cup with “mL” marked on it, you will be able to calculate the volume displaced)
• Water
• Three similar-sized objects such as marbles, pebbles, etc.
• Masking tape (if you do not have a measured container)
• A small scale that measures grams (this is optional—only needed if calculating density)

Directions:

Pour the water into the container, filling it about half-full. If you do not have a measured container, place a piece of tape on the side of the container at the height of the water level. If you are using a measured container, record the height of the water.

Carefully, without spilling any water, place one of the objects into the water. Now observe the water level. Has there been any change? Record it. Add another object to the water. What did this object do to the water level? Once again, record the change. Place the third object into the water and record any changes seen.

Now, think about what happened. What do you think displacement means based on this experiment? What happened to the water? Did you know that the definition of displace is to move or shift from the usual position? Isn’t that what happened to the water in the experiment? The Law of Displacement, which is also called the Archimedes Principle, states that an object immersed in a fluid (like water) is subject to an upward force (buoyancy) equal in magnitude to the weight of the fluid that it displaces. So basically, the water moved or was displaced because of the mass of the object put into it.

If you would like to calculate this further, weigh one of the objects you placed into the water to find its mass. (Technically, weight and mass aren’t the same thing, since mass is inherent to an object while weight is a force and depends on gravitational pull; that’s why things weigh less on the moon. However, since we’re doing these experiments on Earth, we can use the object’s weight as its mass.)

Density = Mass ÷ Volume (of the fluid displaced by one object). For example, if your marble weighed 2 g and it displaced 5 mL when it was placed into the water, you can get the density by dividing 2 g by 5 mL. Therefore, the density is 0.4 g/mL3 (0.4 grams per cubic milliliter).

Why is this important? Like in the story of Archimedes and the King’s Crown, different objects that appear to be the same size may be made of different substances which have different densities.

Archimedes invented many useful things. If you are interested in science, you should read more about him.

Give It a Try #2: Does It Take Up Air Space?

Another Greek scientist was Strato. He enjoyed investigating many scientific ideas and experimented to prove his theories. One scientific idea that Strato experimented to prove was that air has substance and is matter. Let’s learn more and see if we agree with Strato.

Items Needed:

• Bucket or tub
• Water
• Two one-liter bottles
• Drill (to be used by an adult)

Directions:

Ask an adult to drill a hole into the bottom of one of your bottles. Fill the bucket three-quarters full of water. Holding the undrilled bottle with its opening facing down, carefully push it straight down into the water quickly. Does the bottle fill up with water? What happens? Now take the bottle with the hole in the bottom and repeat the same procedure. What happens this time? Does the bottle fill up with water?

Think about what we were trying to discover: Does air have substance? One way to see if something has substance is to see if it takes up space. Did the air take up space in the bottle in our experiment? How do you know? Do you agree with Strato that air has substance?

Give It a Try #3: Using Shadows to Measure

Another Ancient Greek, named Eratosthenes, calculated the circumference of the Earth by figuring out the sun’s ray angle and then using shadows to measure distances. Although sources disagree about Eratosthenes’s exact accuracy, they agree that he was within 10 percent of the modern measurement. The fact that this man could so accurately measure the circumference of the Earth in ancient times amazes me. If you too are fascinated by this, check out the advanced picture biography The Librarian Who Measured the Earth to learn more. Now, let’s “Give It a Try” measuring with shadows.

Items Needed:

• Yardstick
• Bush or small tree (or any straight object outside)
• Sunlight
• A helper

Directions: