Watch the video for an activity description and to preview the resources.
The children will experience the grinding and clashing of the Earth's plates by using an incredible, edible model! First they will follow a given set of directions to explore the idea of plate tectonics. They will work in partners, one person will move the model (graham crackers and Cool Whip) and the other partner will diagram the events. Then the teacher will then use a document camera projector to repeat the process so the entire class can visually see and hear the actual explanation of what is happening. When the experiment is complete, the children can eat Earth's plates! Yummy!
By the end of this unit, called Earth Changes, the children will have to understand how the movement of the crust and mantle creates changes, either quickly or slowly. Thus the children need some background on the layers to help them understand how these events happen. They will be learning about the tectonic plates, which are responsible for the creation of mountains, volcanoes and earthquakes.
Also as a science practice and part of the NGSS, the children are expected to understand and develop models. In this lesson the children will be using diagrams and making a physical replica, which are two different types of models.
I showed the children a model of super simplistic plate tectonics by using a hard boiled egg. For this demo, you will need a hard-boiled egg, permanent black marker, plastic knife and a plate. Click here for step-by-step directions on how to do this demonstration with the egg.
For the children's experimentation, you need the following:
(Make sure to see the step-by-step directions so you are prepared for what you will be doing in this demonstration).
This egg is more than a breakfast food. It is also a model.
Of course I have their complete attention.
This egg is a model of the Earth. The outer shell of the egg represents the Earth's crust since they share similarities. The crust is hard and brittle, just like an eggshell. It is also thin like the eggshell.
I gently crack the shell by tapping it on the table.
Now the shell is cracked into several large pieces. These pieces are similar to the tectonic plates on the earth's surface. The pieces stay right by each other even though they are cracked. You can even see a bit of separation. To make that stand out better, I am going to go over the main cracks with a black marker.
I try to move the "plates" around a little so they can see that the shell sometimes will go over other pieces a bit and sometimes they spread apart.
This is just how the plates of the Earth function. They move around a little bit, but they pretty much stay in the same general spot. When they rub against each other, sometimes they get stuck. When they release, an earthquakes is formed. Sometimes the plates rub against each other and can form mountains. Can you see the mountains that have been formed?
Then I slice the egg in half.
The inside of the egg also models the inner Earth. The white part of the egg represents the Earth's mantle. The real Earth is different though, since the mantle is actually made of rock and is hard. The yellow yolk represents the Earth's core. But remember that the core is actually made up of two parts, the inner and outer core.
So using an egg to model Earth can be very helpful. It can help you understand something you cannot see. I am now able to understand more about the plates and the layers of the Earth. However, using an egg does have its drawbacks. The Earth is not represented completely accurately. Models can be very helpful, we just have to remember that they are perfect representations.
In the next step the children are going to explore the idea of working with a model. Working with a model is very important in understanding models themselves. To see why I have the children create and work with models, click here.
You are going to get a chance to make the Earth's plates move. Do you think we can actually make the Earth's plates move?
No, but we can make a model of the plates move. So you too, are going to be making and working with a model of the Earth's plates.
I then ask questions about the materials that we will use today and relate them to being in the form of a model. I hold up a package of graham crackers.
What do I have in my hand?
Then I show them the Cool Whip and ask the same question.
These items are dessert items that we can eat. But today we are going to be using them for a different purpose. Our graham crackers and Cool Whip are models. The models stands for something else. The graham crackers will represent the crust of the Earth and the Cool Whip will represent the layer underneath, which is the mantle.
I would like you to do some experiments with graham crackers and Cool Whip. You are going to follow the directions on the page and perform the experiment with a partner. One of you will be moving the graham crackers and the other person will be the recorder.
I split the children into partner teams. For this task, I chose to partner the children up according to their abilities since there was going to be a fair amount of writing. I buddied up a lower student with a higher achieving student. This assures that the children will be able to complete the activity with a high degree of success. The higher achieving student can help the lower achieving student, almost like a peer teacher.
So your first decision as a team is going to be to decide which person is going to do which job. I will give you a minute to figure this out for yourself.
I like to give the children the opportunity to work this out for themselves. Making their own decisions is very motivating and is also an essential skill for learning to be part of a team.
Since this is a little tricky to follow the directions and do the movements of the crackers in a precise manner, I demonstrate how to complete the experiments, as on the Edible Earth Changes EXPLORATION recording sheet. I make sure only to guide them, but not tell them exactly what is happening or the Earth movement it is representing. This will be done during the explanation section.
I explain the details of the models that the children just used and the meaning behind it. In order to do this effectively and have all of the children be able to see, I use an Elmo document camera. (If you do not have one, you could put the crackers and Cool Whip on a plate and have the students gather 'round). I give the students each a Edible Earth Changes Explanation sheet for them to record the explanation on. Click here for an answer key for you.
The graham crackers represent the crust of the Earth. The crust is broken into pieces, which is why I gave you two graham crackers. When there is a crack in the plate, we call that a fault. When two plates rub together, changes take place.
Remember when we made different models of the Earth's layers? How many layers does it have? (4) What are the layers? (inner core, outer core, mantle and crust). To help us remember what the layers are, let's sing the song we learned in the lesson Make a Mini Earth model.
I love using songs to help the children remember concepts, steps or other information. Check out this Using Songs and Rhythm Information Sheet for an explanation of why I use this strategy.
The crust includes the ground and the ocean floor. The crust is broken up into large pieces called plates. Do you remember what the mantle of the Earth is like? (It is hot melted rock) These plates move slowly all the time floating on this hot melted rock, called the mantle. The Cool Whip was kind of like the mantle because it allowed for the "plate" to move on top of it. How is the Cool Whip different than the mantle?
When we use models I want the children to be aware of its strengths and weaknesses. In the later grades, they are expected to be aware of the limitations of different types of models so they can chose the most appropriate one for a given task.
Then I continue by demonstrating each of the plate movements written on the paper by using graham crackers and Cool Whip. We go through each of the boxes one-by-one in the order illustrated. Using the Elmo makes such a difference. Everyone can see the visual models easily.
As I demonstrate, I ask the students what they noticed when they were exploring (see video clip). This helps them understand the relationship between their observation, their diagrams and the actual movements of the Earth. We talk about each of the movements and what change actually depicts. The children write down each simplified explanation on their paper (see student sample). Just a note, remember that the sample will look a smidge different since I changed the boxes around (see reflection).
Doing this activity helps them understand the basics of tectonic plates. These plates are responsible for the creation of mountains, volcanoes and earthquakes. They need to understand these events, even if just in a primary way, to better understand if these events happen quickly or slowly to help them attain the NGSS goal (2-ESS1-1).
Today we learned all about the plates of the Earth and how they create changes in the Earth. These concepts will be important to get us to the NGSS goal of being able to provide evidence the events on Earth can occur quickly or slowly over a long period of time.
To evaluate their diagrams, I am looking for these things:
1. Did they label each part appropriately?
2. Was their diagram neat and easy to read?
3. Were their words connected to a part on their drawing?
4. Can I distinguish that a change has taken place? Does their drawing depict a change?
Click to see student sample A, sample B and sample C. On student sample C, I love how the partner team uses arrows to show the direction of the movements. However, some of her arrows are moving in the wrong directions.