Friday, August 17, 2012

"The Browser" show on KSL Newsradio

Our Cheeto Summer blog was featured today on KSL NewsRadio's show The Browser today. They have posted some posted photos of their experiments on Facebook

They featured our Cheeto Helmet and Cheeto Sound Dampener experiments. They didn't focus much on the science of the experiments, just on the fun of doing them. The kids were thrilled to hear their names on the radio. It was a grand end to our Cheeto Summer break.

You can listen to the podcast here. The segments starts at 18:30.

Friday, August 10, 2012

Build A Rocket Launcher For $20

Recently I was reviewing with a friend the modifications our family had made to the rocket launcher described in the Cheeto Cannonballs post. He asked how much it would cost for him to build a launcher. I thought that with some simplifications to the design I could probably build one for $20. This post is to document how to build a compressed air rocket launcher for $20.


I have learned a few things from the previous launchers I have built. First, the air reservoirs don't have to be very big. It doesn't take much air to push the rockets. Larger chambers take more work to fill, which is an issue if you are using a bike pump for pressure. A smaller reservoir also means less cost in materials.

Another simplification is to use the fewest number of parts. Some launcher designs have two reservoirs. The second tank looks cool but adds no functional value. Other designs have lots of pieces to reduce the diameter of the pipes. Each piece adds extra cost.

Also, I tried to use threaded connections whenever possible. Having threaded parts makes it easier to change the launcher afterwards (or fix mistakes).

Finally, many designs require legs or a stand for the launcher. This makes storage harder and requires more time to build and more money to buy the additional pieces. My launcher is in a U shape so no stand or legs are necessary.


Home Depot had pre-cut 2 foot sections of PVC pipe. I used a 1.25 inch pipe for the reservoir and a .5 inch pipe for the launch tube. I chose the cheapest automated valve I could find that had .75 inch couplings. Those three main parts form a U shape, with diameter reducing elbows between them.

Here are the parts I purchased.

Here are all of the parts laid out how they will be assembled. 

The first step was to drill a 1/4 inch hole into the end cap and we screwed the air connector piece directly into the cap. (Our launcher will be connected to a compressor. A valve stem could be place here if using a bike pump to compress the air.) Then we glued the fiew pieces together that weren't threaded.
Finally, we threaded in the sprinkler valve, covering the threads with teflon tape. An embossed arrow on the side of the valve indicates the direction the air should flow. The valve won't work if inserted backwards.

At this point we had a functional launcher for less than $20. All we had to do was touch the leads of the sprinkler value to a 9 volt battery and it worked. This is functional, but not practical. So, for a few extra dollars we added a launch button.

The launch button

We bought a small plastic box from a dollar store. From Radio Shack we purchased a push button momentary switch (4 switches for $3.39) and a pack of 9 volt battery connectors (5 for for $2.69). I drilled a quarter inch hole in the back of the case for the cord and one in the top for the button switch.

One battery will open the valve is the sprinkler leads are connected directly to the battery. But there is more voltage drop across the long connecting cord, so two batteries are required. The 9 volt batteries are wired in series, like this.

I used a long phone cord to connect the button to the sprinkler valve. I tied a knot in the cord inside the box so that pulling the cord doesn't put any stress on the switch. I used an Xacto knife to expose the wires in the phone cord and then spliced one end to the valve and the other to the battery leads.

This was our final launcher built for less than $20, and the launcher system which cost a few more dollars.

We quickly made the rocket in the photo out of paper, a file folder, and tape just to test the launcher. We also like to launch Cheetos! When we have a function that requires a lot of rockets, we usually buy the rocket bodies from It's a Blast.

Further Improvements

In this design the launcher is connected directly to an air compressor. When we actually used this launcher for an event we added a small hand valve so that if the launch button was held down it wouldn't drain the compressor tank.

This launcher works great and it doesn't cost a lot of money to build. It has provided hours of entertainment. 


Saturday, August 4, 2012

Hydro Priming Seeds With Cheetos

Hydro-priming is the process of soaking seeds in water before planting. Hydro-priming decreases the time it takes seeds to germinate. For this experiment, we wanted to test how different concentrations of Cheetos in the water would affect the germination rates of pea seeds. Do you expect that Cheetos will help or hinder the germination of seeds?


For this experiment we used:
700 snow pea seeds
7 plastic cups
8 plastic bags
7 paper towels
1 meat tenderizing mallet
30 Cheetos Puffs
Sharpie to label bags and cups
A squirt bottle


First we labeled each of the cups as follows: Dry, 0, 2, 4, 6, 8, 10. For each cup, we put the indicated number of Cheetos in a bag, then used a meat tenderizing mallet to smack the Cheetos into powder. We then dumped the Cheeto powder from the bag into the appropriate cup.

The next step was to add 1/2 cup of water to cups 0 - 10. No water was added to the cup labeled "Dry." The solutions were thoroughly mixed.

Next, 100 snow pea seeds were added to each cup, making 700 seeds total. The seeds were stirred into the solution. We let the seeds soak overnight.

The next morning we drained and cleaned the seeds from their solutions. The dry seeds were not washed. Seven paper towels were prepared by wetting them and then wringing them dry. Each cup of seeds were spread into the center of one of the moist paper towels. The towels were folded in around the seeds and placed in a resealable plastic bag. Each bag was labeled to identify the Cheeto concentration in which the seeds had soaked. 

Every 12 hours the seeds were removed from the bags so we could count the number of seeds that had germinated. The germinated seeds were removed and the results were recorded. The remaining seeds were misted with a squirt bottle to keep them moist, then rewraped in the paper towel, and put back in its plastic bag. 


Here are the results. Click on the table to make it larger.

Here is a graph of the same information.


The seeds that soaked in the densest concentration of Cheetos were the only seeds that germinated after 12 hours. These concentrations also germinated the highest percentage after all but one of the periods. None of the seeds that were not primed germinated after 48 hours.

It was hard to determine if a seed had germinated. We counted it if part of the root had extended from the seed. If we were to do the experiment again we would only count them if the root were a specified length. Also, since there were so many seeds that germinated between 24 and 36 hours it might have been helpful to count the seeds every 6 or 8 hours, instead of every 12.


Hydro-priming definitely makes a difference. We think it is also safe to conclude that seeds primed in a solution of Cheetos germinate faster, and a higher percentage of seeds germinate compared to seeds primed in tap water. Further experimentation would be necessary to determine if the Cheeto primed seeds would be more healthy, or if the mature peas would taste like Cheetos.