Answer Key | The First Great Lesson

We encourage you to experiment or do research to find the answers to these questions on your own before looking at our answers!

Discussion

No, there weren’t always stars in the sky. A long, long time ago, the Universe was just a big, hot, and super bright ball. Then it cooled down and spread out, and parts of it started to clump together to make stars.

Earth hasn’t been around forever and neither has the Universe. You’ll learn more about how Earth formed and how the Universe started throughout this lesson.

Nothing is a tricky idea. It’s like when you have an empty box with nothing inside. But even in places where there are no toys, books, or anything we can see, there’s still air and tiny things we can’t see. So, real ‘nothing’ is hard to find, even in space because there’s still a little bit of stuff everywhere.

Force of Attraction

Answers will vary.

The pieces should have moved around the surface of the water without any outside force. Some of the pieces should have come together to form different groups. Other pieces should seem to have pushed each other away.

Montessori uses this demonstration to talk about “the force of attraction.” When particles at the beginning of the Universe were attracted to each other, they came together and formed stars, galaxies, the Sun, and the Earth. The same force also pushes some particles away from each other.

“The force of attraction” is not simply one force. It is multiple forces working together that result in attraction. They are forces that cause objects to come together (or move apart) without touching one another. Some examples are:

Gravity
Magnetic Force
Electrostatic force
Adhesion and cohesion

In this demonstration, adhesion, cohesion, the surface tension of the water, the shape of the glitter, and the manner in which the glitter fell to the surface all come together to cause the pieces to move the way they do … but that’s a lesson for another day!

This demonstration represents what happened to all of the particles when the Universe was first forming:

Some particles liked each other, and they came together. Other particles did not like each other, and they stayed separate.

The different groups of glitter that formed represent how the particles that were floating around at the beginning of the Universe came together to form different things: stars, galaxies, the Sun … and eventually, our Earth.

Settling Layers According to Density

The liquids will settle into layers from most dense at the bottom to least dense at the top.

Oil = Least Dense
Water = Middle
Honey = Most Dense

Here is what we know (we learned the first 2 statements in First Great Lesson):

When particles cool, they huddle together very closely.
When the Earth was forming, particles in the center warmed and rose up to the outside. Particles on the outside cooled and sank down to the center.
The densest liquid is the one that sank to the bottom of the cup.

If cooled particles sink, and they are also close together, we can guess that the densest liquid (the one that sank the lowest) probably has particles that are close together.

Learn more about density here.

Volcano Model

Answers will vary. The main components of a volcano that we want to demonstrate in the model are a hard crust, red hot liquid inside, and gas bubbles that rise out of the volcano.

When you mix the baking soda, soap, and food coloring together, some observations you might make are:

It mixes
It turns red
It gets wet

When you add the vinegar some observations you might make are:

It bubbles/fizzes
It comes out the top
It explodes

There are many different things you could do:

You could add more or less vinegar – it might make the reaction bigger or smaller.
You could add more or less baking soda – it might make the reaction bigger or smaller.
You could add more or less soap – it might make it more or less bubbly.
You could take away any of the ingredients – taking away baking soda or vinegar would stop the reaction completely.

When Earth was first forming, it was very hot and chaotic. Eventually, the Earth started to cool, and a solid crust formed where the warm Earth touched the cold outer space. Under the crust, the hot liquid Earth was still there.

Today it is even cooler, and the crust is thicker … but the hot liquid center still remains. Some of the particles in the center get so hot that they become gas. The gas forms bubbles in the liquid rock. The gas wants to rise, so it pushes the liquid rock to Earth’s surface. We call the places where this happens volcanoes.

In this demonstration, you mix vinegar and baking soda together to cause a chemical reaction. That chemical reaction quickly creates a lot of gas. The gas forms bubbles in the soap. The gas wants to rise, so it pushes through the opening in your “volcano” in the form of soap bubbles.

Learn more about the upward force of gas in Force Direction of Solids, Liquids, and Gases.
Learn more about volcanoes in Effects of Moving Tectonic Plates.
Learn more about chemical reactions in Combining & Separating and The Story of the Elements.

Volcanoes are made of hot molten rock, ash, and gases. Learn more about volcanoes in Effects of Moving Tectonic Plates.

You’ll have to research this one on your own!

Volcanoes usually form at tectonic plate boundaries or hot spots where Earth’s crust is thinner. It is easier for gas and molten rock to push through thin crust than through thick crust.

Learn more about volcanoes in Effects of Moving Tectonic Plates.

The First Great Lesson

Prep

Answer Key | The First Great Lesson

Discussion

Force of Attraction

Settling Layers According to Density

Volcano Model