Introduction: Particle Detector

This project will allow you to see particles moving in your own home with the use of inexpensive materials.

For this project we used:

  1. 10 gallon fish tank with lid
  2. Felt, enough to cover the bottom of the tank
  3. Glue, we used craft glue
  4. Isopropyl Alcohol (90%+)
  5. Dry Ice
  6. Container for the dry ice that is bigger or the same size as the tank

Cost of Materials (at most):

  1. Tank: $20
  2. Felt: $0.50
  3. Glue: $1
  4. Isopropyl Alcohol: $3
  5. Dry Ice: $8
  6. Container: $5

Total estimated cost: $37.50

This project can be completed in a day, though we took about two total for all of our materials to be collected.

Possible Improvements: The final result is a lot easier to see with a black base opposed to tan, like we had. Doing it again, we would use black construction paper on top of the dry ice container, or use a darker container. We also soaked the felt, and the alcohol ran down the sides, making the particles harder to see as well.

Step 1: Glue the Felt to the Bottom of the Tank

Before you start the project, it is best to start with a clean, pristine tank for visual benefits. Then put the glue on the inside bottom of the tank and add the felt. We didn't overlap felt, we cut to size instead. Gaps are okay as long as the majority of the tank is covered.

Step 2: Add the Isopropyl Alcohol

Saturate the felt, but don't soak it. If you add too much alcohol to the felt, it will run down the sides of the tank and make the particles harder to see in the final step.

Step 3: Add the Dry Ice

We put the dry ice on the lid, and placed the container over the dry ice. We then flipped the tank upside down and over the container with the dry ice. We also placed Styrofoam underneath our lid and duct taped the sides because the lid we chose had holes in it. You can either duct tape it or insulate it like we did. You can place the dry ice in a container bigger than the tank and then the tank lid over that container. You should be able to see alcohol mist falling from the felt to the top of the container.

Step 4: Turn the Lights Off and Shine a Flashlight Through

When you turn the lights off and shine light through one side, you should be able to see a thin layer of an alcohol cloud form along the bottom of the tank. If you look closely, you can see thin streaks moving in all directions. Those are the particles.