Physical Science Module 6: Earth and the Lithosphere.
This module has been the most exciting for the students to learn, all because of Experiment 6.2: A Simulation of Plastic Rock.
Plastic Rock – Rock that behaves like something between a liquid and a solid. It is in the astehenosphere.
This experiment is made with a mixture of cornstarch and water. First you mix a portion of water and cornstarch together in a pan. I found in my cabinets two old round cake pans that worked really well. The high sides kept the mixture inside the pan, well most of it.

Here is a helpful tip. Put paper or cloth down on the table before opening the cornstarch. This is for easier cleaning later. As you can see in the picture above and below, just looking at cornstarch makes it go all over the place.

After mixing water and cornstarch, you want to get a nice smooth gravy and then add more cornstarch.

Below the young men are trying to mix the cornstarch at the beginning. It is difficult at first, but they keep at it.

This was not fun part!
The fun part was playing with it. 😀

When plastic rock is hit by a force it becomes a solid. When left alone to relax, it becomes a liquid. The young ladies above are spooning it out, which causes it to solidify and then it relaxes and drips off the spoon.

The young men are showing the same results above. Notice that the young ladies use spoons and the young men are using their hands. LOL That doesn’t last long. Take a look at the next picture.

All three of the young ladies got their hands in it and didn’t want to stop playing with it. Squeals of delight were heard! Notice the blob on the right is hard, while the one in the center is slowly beginning to droop. Cool, don’t you think?

Above is another picture of the young ladies. Look at those faces. All three of them are just lovely and they had the best time. I have great students.
Because this experiment took a little longer than others and because no one wanted to stop playing with it, we had time to do only one other experiment.
Part B of Module 6, Making an Electromagnet and A Model of Plate Tectonics
Check out Sahm I Am post on this experiment.


My oldest played around with this here at home just the other day. The others join in when they saw what fun he was having and they had a messy time of it.
I did think of using it for my science class – now that I have read your post, I am going to. 😀
I love playing with that stuff. Of course I didn’t actually know the technical sciency term for it, (we just call it smoosh and we add food colouring to it) I really enjoy these science posts of yours. Makes me wish I was one of your students!
You are making me want to offer to teach a science class for my homeschool group. Stop it! LOL
Gotta admit that you’ve managed to make the one subject I took in school to actually be fun!!
Thank you for sharing this website. It is a wonderful benefit for the Co-Op class I am teaching. The students loved doing your bingo vocab idea. Every week they want to play Vocab Bingo. Being a single mom, my time is limited, so this website has been invaluable to me. You have provided information at my fingertips and fun encouragement. THANK YOU.
Thank you for your comments. 🙂
This is great. I’ve seen that experiment done, and never saw a use for it. Now I know that it can represent the rock that makes up the asthenosphere, I really understand it. =)
Another thing you can do with this, if you are brave and have room, is put a large amount in a tub or bin, and have the students jump on it with their bare feet. If they jump hard, they will initially stay on top, and then sink down. Maybe they can keep jumping a few times.
If you don’t want to do this, have them slap the pan of mixture with their palm. They’ll be able to feel the initial resistance.
I’ve actually seen on YouTube people have been able to RUN across a small pool (about 10 feet long) on top of this stuff!
Hi Marty,
Thanks for visiting my blog. I have also seen that video on YouTube and had given the link to my students. They enjoyed it. 🙂 The students played a long time with this experiment, so they did feel the resistance. This was their favorite experiment and requested to do it again at the end of the year when I asked what they would like to do. It was fun.
oh shoot! I forgot about this experiment!
We’re using 1st edition, and this one wasn’t in there.
I’m going to have to do it next week. =)
Hey! I searched in my Physical science textbook and couldn’t find this experiment. (I wanted to show my younger siblings because I remember just how mesmerized I was when I did this!) Thanks for posting! 🙂
Hi Grace, You have the 1st edition. This experiment is in the 2nd edition. You can google the experiment and find instruction on how to make it. 🙂