Introduction: How to Make a Simple Spray

About: I do engineering design for machines and electronics but do love science, art and history.

This idea comes from the mechanism of a carburetor. According to Youtube’s video (, we can simply mimic the mechanism of a carburetor with two straws. However, I found that this is quite difficult to control the performance of the experiment. Thus, I build this simple thing to hold the position of straws. In addition, we can see that this mechanism has been used in a spray bottle too.

Therefore, this thing could help you to conduct the experiment of studying the mechanism of carburetor or the effect of air pressure and you can use this thing to make a simple spray bottle.

You need:

1. Two straws of 10 cm length (I cut a long straw of 5mm diameter into 2 pieces.)

2. A cup of water

3. The part of the body

Step 1: Build the Body Component

You can use your own method to make it or simply use a 3D printer to print this part.

This part is designed to hold two straws of 5mm diameter. You can download the FreeCAD file to change the body’s size or the hole’s size.

Step 2: Assembly

Just insert the straws into the two holes.

Step 3: Use As a Spray

Put the combined thing into a cup of water. The water level has to be high enough, around 1~2 cm lower than the mouth of the cup.

Step 4: What Can You Teach or Discover With This Thing?

You can use this thing to set up an experiment with students or kids and ask them to discover the effect when they have tried to blow the straw.

I have prepared an example worksheet for you. The aim is to introduce atmospheric pressure or the physical science of air and liquid. You can prepare the materials for your students or kids. You may need the followings.

  1. A worksheet which will have the instruction of building thing and questions. (I have attached a sample worksheet.)
  2. Two straws of 10 cm length and 5mm diameter. (You can use other straw with different dimension but you will have to modify the 3D model.)
  3. The main body. (You can print this by a 3D printer or make this by other material and method.)

In addition, you could launch a 3D printing session for your students or kids. I hope this project would be useful for teaching science and technology. Wish you enjoy this build!