Cornstarch Monsters Which frequency makes the best cornstarch monsters? email to friend
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Written by Jack Spangler

I saw a video on the Internet where someone put a mixture of cornstarch and water into a speaker and the thick liquid looked like it came alive… like a monster. However, the video didn’t explain how it worked. I need to find out if any sound will vibrate the liquid or if there is a specific sound that makes the best cornstarch monster. Here's my hypothesis... I think that a high frequency will make the liquid vibrate or move the most.

Materials

I went to the thrift store and purchased an old speaker and hooked it up to an amplifier. I found a free tone generator online and ran it into the amplifier. The thick goo is called a Non-Newtonian mixture or sometimes people call it Oobleck. To make the special liquid, I mixed one box of cornstarch with a cup of water.

Cornstarch Monsters Materials

Experiment
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Test #1 - High Frequency 1000 Hz - I lined the speaker with a plastic bag and poured the cornstarch into the cone. I set the tone generator to 1,000 hertz (1 hertz = 1 cycle per second). I kept the volume constant at “5” in each one of my tests. As you can see, the cornstarch did not vibrate at all. The tone sounded very high pitched. I discovered that my hypothesis was wrong, so I needed to conduct some more experiments.

Test #2 - Try 500 Hertz - Changing the frequency will be my variable. I tried 500 Hertz and the results were disappointing. Nothing really happened.

Test #3 - Try 100 Hertz - This was a good test because I saw the cornstarch mixture start to vibrate for the first time. It looks like the low frequency makes the cornstarch and water move the most.

Test #4 - Try 50 Hertz - I set the tone generator to 50 Hertz and turned the volume up to “5” and the cornstarch monsters started to appear (just like I had seen online). I learned that 50 Hertz means that the speaker vibrates back and forth 50 times a second. You can see in the picture how the cornstarch mixture started to move. Lower?

Test #5 - Try 20 Hertz - The experiment using 50 Hertz shook the speaker so much that it tore the plastic and actually started to tear the speaker. My Dad repaired the speaker and I got a new bag. I used the same cornstarch from the last experiment to make sure I kept everything the same. As you can see, 20 Hertz is the best frequency!

Observations

This is the first science project where I had to perform this many tests to finally arrive at an answer. My first hypothesis was wrong and this made me create a new test. When that test didn’t work, I made up another test. The data from each test (how much it vibrated) helped me decide what test to run next. I had to be reminded several times not to change anything other than the frequency. Now I’m going to put my discovery on YouTube and explain how I did it so that someone else can recreate my experiment.

Cornstarch-Monster-20Hz

How does it work?

After I completed my tests with my Dad, I still didn’t really understand why the lower frequency made the cornstarch move more than the high frequency. To answer the question, I interviewed a professional sound engineer, Mr. Howard Megregor from Engineering Dynamics.

When I visited his laboratory, he set-up his own version of my experiment using his very expensive speaker, amplifier and tone generator. When I told him that 20 Hertz worked the best, he dialed in the same frequency and he said that I was correct. Mr. Megregor told me that a “Hertz” is a measure of how many cycles (like a vibration) there are in a second. The high frequency has lots of vibrations, but there is not enough motion in the speaker to vibrate the cornstarch liquid.