All posts by bob

The Egg Drop Challenge!


You will need:

  • 1 plastic cup of water with a mouth wide enough to fit the egg.
  • 1 10” (25 cm) piece of cardboard or a small tray with a SMOOTH bottom
  • 1 cardboard tube (paper towel or toilet paper tubes work well)
  • 1 Egg (uncooked for more drama)

What to do:

  1. Place the tray centered over the cup
  2. Place the tube on its end in the center of the tray
  3. Place the egg horizontally on the tube
  4. When ready, strike the tray hard enough with your palm to send the tray flying, but not so hard you hit the glass of water. If all goes well, the tray and paper tube will go flying, but the egg will safely drop into the water.

How does it work?

INERTIA describes an object in terms of how much energy is needed to move it or stop it from moving. Since the tray and tube are very low mass (lightweight,) they have very little inertia, and will easily move out of the way.
The egg, however is heavier (has more inertia) and so it is not easily moved, leaving it in place for gravity to bring it down into the cup.

Elephant Toothpaste Experiments with Mark Rober!

How do you fill a pool with foam in 5 seconds? It’s not an easy task. After demonstrating the classic Elephant Toothpaste reaction in countless ways over the last 8 years, and even setting the Guinness World Record for the largest Elephant Toothpaste reaction, I thought I had seen it all – then Mark Rober called. Mark is a talented engineer, YouTube All-Star, and all-around great guy who wanted to take the classic demo to new heights – literally!


What you don’t see in the video, however, is the days of testing  that went on behind the scenes to pull these demonstrations off. It turns out that, at a large scale, Elephant Toothpaste can be a fickle demo; slight variations to the chemistry, and the reaction can increase, or decrease significantly. If you change the temperature of chemicals a bit, or mix the chemicals a little longer, it can be the difference between filling a pool, and, well, overflowing it.

The Elephant’s Toothpaste Reaction requires 3 things:

    • Hydrogen Peroxide
    • A catalyst (often potassium Iodide or yeast)
    • Soap

Hydrogen peroxide is basically water (H2O) with and extra oxygen (making it H2O2 ) But don’t be fooled into thinking it is close to water. Concentrated hydrogen peroxide can result in a strong chemical burn if it gets on your skin. To create the elephants toothpaste reaction a second chemical is added (know as a catalyst) which basically tears-apart the hydrogen peroxide into water while releasing Oxygen gas inside the bubbles.

The reaction can be triggered in lots of ways. In all the videos other than the giant pool version, we use a solution of Potassium Iodide to break apart the molecules. For the pool version, we wanted it to be safe to touch, so we started with a diluted hydrogen peroxide solution and used off-the-shelf dry yeast mixed with water as the catalyst. Yeast contains an enzyme called Catalase that does the job of breaking down the hydrogen peroxide. It also creates a kind of foam that tends to hang around a bit longer. (GET DIRECTIONS FOR THE YEAST VERSION HERE.)

It took 3 tries to get these to hit right on, but the effort was worth it with a perfect crash.

This was a test of the Elephant Toothpaste filled balloon. A piece of scrap wood with a needle on it acted as a spear. The result was beautiful.

This carousel of foam was one of our experimental surprises. The foam was supposed to go higher, but we top-loaded the reaction with food color which diluted the peroxide. It is one of my favorite shots in the video. Here’s an extended clip.

We scaled up using a 5 gallon bucket, and then a kiddie pool with the hope of getting the foam to just reach the top of the pool and this first scaled up test was promising:


Why did our foam overflow the swimming pool? There are many variables in this experiment that ranged from the temperature of the chemicals, to the addition of water from food coloring, to the efficiency of the mixing of the yeast and water. We’re still not exactly sure what bumped up the amount of foam, but let’s face it, it was better to overflow the pool than have it come up short.


One of the nice things about the reaction is that it breaks down into generally harmless,  bio-degradable components when the chemistry is correct. (Basically you end up with soapy water with small amounts of  either iodine or yeast in it) Cleaning the pool was simply a matter of hosing down the coloring and soap and disposing of what was left down the drain like you would after doing the smaller, home version.

Make Ice Cream in a Plastic Bag!

You will need:

  • 4 oz of milk
  • 4 oz of cream
  • 1/4 tsp of vanilla (or use other flavors usually found near the vanilla in a grocery store – you can use chocolate syrup for chocolate ice cream)
  • 4 tsp of sugar
  • A few drops of food coloring (optional – if you want colorful ice cream)
  • Lots of ice
  • Lots (half cup) of salt. Rock salt (sold at hardware stores) works best.
  • Small (quart size) zip-lock freezer bag
  • Large (gallon size) zip-lock freezer bag


What to do:

  1. Put the milk, cream, flavoring, coloring, and sugar into the SMALL zip-bag and zip it shut (be sure it is zipped up and closed completely)
  2. Put about a cup of ice into the large bag and the cover the ice with a small handful of salt. Put the small bag with your ingredients into the larger bag.
  3. Add some more ice and then some more salt. Keep adding salt and ice until the bag is almost full.
  4. Zip it shut (be sure it is zipped) and then carefully hold opposite sides of the bag and shake the bag back and forth (like your steering a car) for about 5-8 minutes.
  5. Open the larger bag and take out the smaller bag – it should be full of ice cream! Rinse off the bag under running water to remove any salt that may be near the opening of the bag.
  6. Open and enjoy!

The Science of Ice Cream
When you added salt to the ice, the chemistry between the two forced the ice to melt. Before the ice could melt though, it needed to borrow heat from objects that surround it. This is called an ENDOTHERMIC process. Since your ingredients are not as cold as the ice, it borrowed heat from your ingredients making them colder! When they get colder, they freeze up into ice cream. Yum!

More Science on Jimmy Kimmel Live!

I had another exciting appearance filled with explosions, tornados, and, well, salad. Let’s break down some of the science.

First watch the video!

Toilet paper tornado on Jimmy Kimmel Live!

This easy-to-do demonstration allows you to have a visual representation of the centripital energy of the spinning blades and the opposing energy of the moving air created by the blades. This creates a simulated vortex of toilet paper. If you plan on trying this out, here are some tips:

  • Use cheap, lightweight toilet paper for the best results
  • If you use a smaller fan, you may have to trim the toilet paper lengthwise
  • Experiment with different lengths of toilet paper to get the best vortex.

If you make your own Toilet Paper Tornado, (and you should) be sure to tag it #toiletpapertornado in your social media posts so I can shout it out.

Jimmy Kimmel exploding Hydrogen

Many of you may have seen a sign in a hospital that reads, “NO SMOKING – OXYGEN IN USE” and would logically assume that oxygen is flammable. This demonstration showed two traits of oxygen; first, that oxygen is NOT flammable at all, and second, that oxygen can intensify any fire. (the reason for the hospital warning) The balloon filled with hydrogen and oxygen burned very fast and very loud. I could easily feel the shockwave of the the last balloon where I was, and many of the crew said they could as well. Incidentally, the explosive reaction of the hydrogen and oxygen likely produced some water (H2O) during the reaction.

Jimmy Kimmel Live Vacuum Cannon on stage.
This is the mylar cap after firing the vacuum cannon.

The vacuum cannon is a simple concept: remove most of the air from a tube, and then use air rushing back in to propel any object in the tube. In our early tests with a ping pong ball, we were able to use a chronometer to clock the ping pong ball leaving the barrel at 845 feet per second – over 350 miles per hour! We were even able to blast the ping pong ball right THROUGH a ping pong paddle. Since we were able to move a ping pong ball faster than a “speeding bullet,” we thought it would be fun to see if we could actually get a model of Superman to faster than a speeding bullet.
A model of Superman was sculpted by Jon Neal specifically for this demo and then cast in rigid foam. While it it never got through the brick wall, it certainly did quite a bit of damage to Superman.

The salad cannon was an epic build that brought together several talented people to make it happen. The original idea was to build basic “potato” cannons, fill them with veggies, and trigger them all at once. My crew determined it might work even better if we used a piston-style system which creates a more intense release of air through the barrel. We also decided to build an ‘Electronic Menu” that would allow Jimmy to select the items he wanted in the salad and then trigger them on command. We used some commercially available chopping blades at the end of each cannon to slice the vegetable instantly as they exited the barrel. The only exception was the lettuce which got cut to the perfect size just from the force of the air blast. The array required lots of custom parts and electronics and it took over a week to build and test.

It was a lot of fun putting these demos together and working with the uber-talented team at JKL.

Science onward!

Explore the Science on Jimmy Kimmel Live!

Ready to learn more about the science seen on Jimmy Kimmel Live? Watch the segments below and then dig in and check out the science behind the demos!


This was a fascinating demonstration that shows just how much air expands when heated. The boiling water cause the air in the flask to heat up and expand, pushing the heated air out of the flask. When it was turned upside down into the water, the air cooled and condensed, creating a vacuum that sucked in the water. The amount of air in the flask after the demo filled the entire flask when it was on the heater.


The “String Thing” demonstrates some amazing physics of a fast moving loop of string. I have had a hard time figuring out the actual physics involved in this demo. It is based on a smaller toy version and a design by physics teacher Bruce Yeany.

Below you can get the instructions and equipment list to make your own string thing. Play around and explore device and post a video telling me how you think it works. Be sure to put Science Bob in the video title so I can find it easily.



I love the elephant’s toothpaste demo and have done it MANY times in many ways.
This is a decomposition reaction that separates oxygen from hydrogen peroxide. Add a little dish soap and you have some serious foam. Try the home-version by clicking >>HERE<<

The Venturi Effect Ping Pong Ball Blaster


This was a lot of fun to develop. I was based on a design by Adam Savage, but his version was limited to the amount of ping pong balls in the tube. By adding a hopper I was able to shoot 600 ping pong balls in about 2 minutes.

The original design was a little…aggressive.

That prototype used the strongest bouncy castle blower I could find. It worked great but the balls traveled way to fast to be safely used on stage.

Stay tuned for more details and build photos!

Science Bob Sets a Science World Record – Largest Elephant’s Toothpaste!!

On a recent appearance on Live With Kelly & Ryan, Science Bob performed his messiest and biggest demonstration yet! In the process, he also established a new Guinness Book World Record! His demonstration was based on the classic Elephant’s Toothpaste demonstration which uses some decomposition chemistry to create a LOT of foam from a small amount of liquid.

Check out the HOME VERSION of the experiment (above) by CLICKING HERE.

When it came to the record breaking version of the experiment, Science Bob scaled everything up, from the size of the container to the concentration of the chemicals. In all, over 40 liters of hydrogen peroxide and more than 8 liters of catalyst were used. In addition, Bob constructed a bucket tipping system so that the demonstration could be done without the change of getting him covered in foam.

Three adjudicators from the Guinness World Record offices were on hand to quickly jump in and began taking measurements of the foam as soon as the commercial break started. The record to beat was 5 cubic meters, and the final calculation for this demos was over 13 cubic meters!

Tesla Coil Guns!


To bring these Tesla Coil Guns to life on Jimmy Kimmel Live, I elicited the help of Steve Ward and Philip Slawinski who had previously built Tesla Coil guns for fun. While the guns were impressive, they were also too powerful to use indoor since they could possibly damage the electronics in the cameras and stage equipment which costs hundreds of thousands of dollars. To get around this problem we brought in engineers to design a custom grounding system for the studio. We also made custom grounding footwear out of snowboard bindings so that the units did not have to be grounded directly through the building.

For fun, I wondered if the coils might be able to ignite balloons filled with explosive hydrogen. In a late night test session, it was discovered that they wonderfully exploded with just the microsecond spark of the guns.

While the arc from the gun would not likely kill someone if they were to get hit by a bolt, I can tell you it is certainly uncomfortable. In fact, it you were to hold the gun too close to your body, the arcs of electricity could turn and hit you.

I’m not sure Nikola Tesla would have ever imagined a Tesla coil gun, but I bet he would like it if he saw it.

My Sci-Fi Themed Classroom!

What do you do when you’re an elementary school science teacher and you’re given a room with NO WINDOWS!? If your a bit of a geek and a maker like me, you turn the room into your very own STARSHIP CLASSROOM.


Let’s face it, building a science-fiction based room is any geek’s dream build, and if you’re a student coming to a startship classroom, hopefully it makes learning even more fun. Best of all, I got to learn a lot of new skills in the process of creating this.  I used maker skills that ranged from 3-D printing, to computer controlled routers, to coding and electronics. Here are some of the basic elements of the room, and how they were made:
Original_ClassroomThe room started out looking like a typical science classroom. But that would soon change.


Sensor ArrayThe sensor array on the ceiling has no practical purpose other than looking cool. It was made of some scrap plywood and uses a smokey security dome that I got from a store going out of business. I added some holiday lights and put a color changing globe inside of the dome which had a really nice effect. It ended up looking like it belonged in the Death Star, which I considered a plus.

IMG_2296Here it is under construction. Fairly simple in design, but it looks pretty cool.


panelsThe control panels were much more complex. The lower part was created by designing a layout on a computer by adding holes and openings  for various buttons and lights I had. I then had these laser cut to size in black plexiglass. I could have drilled the holes, but many of the buttons were square, and I was fortunate enough to have access to a laser cutter.

The panels used numeric counters, LEDs, buttons and switched that I had, or sourced on eBay. The lighting effects were done using a modified Arduino controller to create the blinking and patterns. The video monitors were some hacked video panels that used to be part of a store display. I found these on eBay for about $8 each. I created the displays from some templates I found on-line, and then, for fun, modified them with some hidden easter-eggs of teachers names and school locations.

IMG_4063The round sphere on the left panel has a color changing LED Christmas ornament under it for effect. The two numeric displays on either side are voltage displays which I hooked up to the LED. Because the different colored LEDs require different voltages the displays continually change in sync to the LED colors.

IMG_4061Inside the control panels – that’s a LOT of wiring.


doorI love the airlock door – mainly because every now and then a a maked something you build from scratch turns out looking just how you imagined it, and this was one of the few things that did. I designed this door using Apple Pages (really!) and then transferred the design to a CNC program (VCarve) which would allow me to to use a computer controlled router to cut all the grooves with a level of precision that I could not accomplish by hand.

I should probably point out here that I do not own a laser cutter or CNC router – I am part of a wonderful community maker space that gives me access to an amazing amount of equipment and talent that I am lucky enough to utilize every day.

woodI originally cut the door out of wood, but it looked pretty bad and would take many hours to sand smooth, So I then tried 3/8 inch expanded PVC which is often used for house siding and trim. The results were exactly what I was looking for and it was practically ready to hang!

IMG_5780The video display on the door was made using an old digital photo frame that could play video files. I created all the graphics in Apple Keynote and exported them to video files. They loop endlessly. I hid the frame in some scrap pieces of the expanded PVC. The buttons were made on a laser cutter and have no function. The door was simply applied over the existing door with double stick tape. I added some signage and caution tape and the airlock was complete.



Command centerThe Command Center is a favorite part of the room, and the best part is it is a real movie prop! This was the main console used in the 2004 movie, Thunderbirds.

thunderbirdsHere is my console being used by Oscar winner Ben Kingsley!

IMG_2859I purchased it from a source in England and had it shipped to the US. The console was pretty beat-up and required a complete renovation that took several weeks. First job was to patch, repair, and paint the base.


I then rewired and replaced many of the lights and completely reorganized the wires. For fun, I also added a sound unit which allowed me to add 8 computer-voice sound effects when various buttons were pushed.

New Console WiringThe room has many other features in the way of lighting and Sci-Fi decorations.

If you’re thinking it would be cool to do this in your house or shop, go for it! I learned (and failed) a lot along the way and the internet is filled with wonderful resources to get you started. Keep exploring, keep making!


Juggling in Lunar Gravity!

This video shows what it would be like to juggle on the moon (without a space suit.) This was filmed aboard a plane that makes parabolic flights up and down. As the plane descends, it can simulate partial or complete weightlessness for about 20-30 seconds.

The moon’s gravity is about 1/6th of the earths gravity. That means things fall a lot slower. It also means if you wanted to learn how to juggle, the moon is the best place for sure!

The Science Behind The Camera on Jimmy Kimmel Live

If you saw my science demonstrations on Jimmy Kimmel Live, and want to learn  more, you’ve come to the right place. First, watch the entire segment below:


If you look carefully, you can see the edges of the 4 flasks that are inside of the aquarium.

Oil & Pyrex Glass
While we may think of light traveling at a constant speed, it’s speed can vary depending on the material it is passing through. In fact, light can slow down as much as 50% when it passes through diamonds. How light passes through objects is known as the Index of Refraction. On the show, we demonstrated how light passes similarly through regular cooking oil and Pyrex glass. This means they have a similar index of refraction and so the Pyrex glassware will virtually disappear in the cooking oil.

TRY THIS: If you have some vegetable oil sitting around, fill a container with the oil, (preferably a clear container) and place a Pyrex glass measuring cup in the container of oil. You should see that the glass part of the measuring cup disappears!


Glowing Phosphorus
This awesome demo showed the significance of oxygen when it comes to fire and combustion. The demo uses a deep red powder called RED PHOSPHORUS. Red phosphorus is a flammable powder that burns somewhat slowly. When ignited, you can see it burn and give off smoke. The giant round boiling flask is filled with pure oxygen, and as soon as it is placed over the burning phosphorus, you can see an immediate change as the phosphorus begins to burn vigorously, glow brightly, and fill the flask with a luminous-looking smoke.

This phosphorus demonstration is quite old and historic – it goes back to the 1600s when German Scientist Hennig Brand created white phosphorus by boiling hundreds of gallons of urine in a quest to create gold. Unfortunately, there was no gold in his future, but he did notice the white phosphorus he created would glow, or become “phosphorescent.” White phosphorus, by the way, is much more reactive than its more stable allotrope red phosphorus, which we used in the demonstration.


Making Liquid Methane
Pyro-technician, Steve uses liquid nitrogen and and modified copper tubing to make liquid methane.

Liquid Methane Fire
This demo really looked great on camera. Methane gas is a flammable fossil fuel that is commonly used in homes for cooking and heating – it is the main component of Natural Gas. We took methane gas and ran it through a modified copper tube submerged in liquid nitrogen – this cooled the methane below its boiling point, turning it into a very cold, very  flammable liquid.

  • Liquid Nitrogen: -196°C (-321° F )
  • Liquid Methane: -161°C (-258°F)

The demo also highlighted something called the Leiden-Frost effect.  The best way to think about the Leiden-Frost effect is to consider how cold water on a hot pan skitters around the surface of the pan. This is because it is suspended on a layer of steam as soon as it hits the pan. The same happens with liquid nitrogen and liquid methane – as the cold liquid comes in contact with the much warmer floor of the stage, it instantly begins to boil and spread across the surface. The drops  of liquid methane will remain on fire while they vaporize creating a very cool skittering fire effect.

film_canister_gatling_gunThe Tesla-Coil Triggered, Ethanol Powered, Film Canister Gatling Gun
It was time to have a little fun with science. The concept of putting a small amount ethanol into a film canister and triggering it with a spark has been around a while. But I wondered if I could daisy-chain spark gaps to create a device that would blast multiple film canisters in succession. After several tests and tinkering, I found a system that worked using a 6,000 volt Tesla coil for sparks, and wheel made of a material called Gatorboard which was non-conductive and could keep the sparks where I wanted them.

Watch the build and testing in the video below:

If you like science and maker projects, I hope you’ll consider subscribing and also joining our Facebook community by clicking HERE. Thanks for checking out the page, and keep exploring our amazing world of science!


Science Bob on Nicky Ricky Dicky and Dawn

Quad FoamWhat’s it like to be on Nickeloden’s Nicky, Ricky, Dicky, & Dawn? It’s awesome! And in one of my guest appearance, we got to use some real science! Here’s a behind-the-scenes look at the episode, as well as a way for you to try some of the science experiments from the show at home!

In the episode, Mae  calls on Science Bob to convince the Harper quadruplets (Casey Simpson, Mace Coronel, Lizzy Greene, and Aiden Gallagher) that there is no such thing as bad luck or curses. This eventually leads to Ricky (Casey Simpson) performing some exciting, yet messy, science demonstrations in the Harper home to prove a point.

So, did the episode use some kind of special effects to create the experiments? No way…the producers wanted to use real science with real chemical reactions!

Dawn’s vinegar and milk experiment will not only make milk chunky, it can turn it into plastic! There’s a bit more to it than you see in the episode, but if you want to try it yourself, CLICK HERE.



Science Bob and Casey Simpson (Ricky) test out the Elephant Toothpaste reaction outside the stage before performing it on set. Thanks to Casey’s mom for this great photo.

There were no special effects tricks there, that was real science! The “big foamy snake” was actually a dramatic chemical reaction sometimes called Elephant Toothpaste.

Click the foamy bottle to learn how to try the experiment at home!

In the big flask was  hydrogen peroxide, blue coloring and some dish soap. The hydrogen peroxide we used was stronger than the kind you find at the pharmacy, and it can irritate your skin, so Casey’s gloves and goggles were not just for show. When the other chemical, (sodium iodide) was added to the flask it triggered the production on millions of tiny, foam bubbles…and a big mess.


During the first take of the scene, the foam did not go very high, so the producers asked to try it again. On the second take, (the one they used on the show) the foam went so high, it hit one of the lights in the studio!

The second experiment used the science of food (molecular gastronomy.) When you add Sodium Alginate to a liquid and then put it in some water with Calcium Chloride, you get watery blobs of gel that you can eat!

Casey Simpson and Lizzy Greene tested the "olive" experiment to make sure it was really science.

Casey and Lizzy test out the “olive” experiment
in the Special Effects trailer to make sure it was really science.

But wait, there was some more movie-magic at play during the scene. It one point, the pen in my lab coat had to leak on cue. How did they do that? The Special Effects Department set up very long tube that went from the pen, down my shirt, to a special effects crew member lying down behind the couch on the set. When he heard the cue, he started pushing watery paint through the tube – it worked perfectly.

special_effects_bagWant more Hollywood magic? As part of the scene, the handle on my suitcase had to break off at just the right moment. Believe it or not, it was actually triggered by remote control! The special effects crew modified a real suitcase with a special trigger and a receiver. When they wanted it to break, they simply pushed a button on a remote control off-stage.

Science is everywhere, from medical labs, to Mars rovers, to, well, the set of Nicky, Ricky, Dicky, & Dawn.


Never stop exploring!

Science Fun on Jimmy Kimmel Live

It was time for some more science on Jimmy Kimmel Live! This visit it was time for some fire, ice, and fun chemistry.

IMG_4537Liquid Nitrogen Powered Bottle Rockets
The first demonstration utilized liquid nitrogen as thrust to power a standard soda bottle. Nitrogen makes up 80% of the air we breathe. And liquid nitrogen will increases its volume 700% when going from liquid to a gas! Because of this, we were able to create pressure without an outside source.

(NEVER place liquid nitrogen in a closed container – many have been hurt attempting this) For this demonstration I custom designed a bottle launcher with several safety features including pressure gauges and blow-out safety valves. Many safety tests were done to test pressure limits of the bottles under several liquid nitrogen conditions as well as launching tests. Ultimately, the pressure needed was far below the pressure limits of the bottle. Eventually I will try this as a vertical rocket with fins and a nose cone.

briggs_reactionBriggs-Raucher Chemical Reaction
The cool oscillating reaction used on the episode was called the Briggs-Raucher reaction, named after two high school science teachers in San Francisco who designed the demonstration. It is one of a very small number of chemical color changes that is able to repeat itself multiple times. Solutions include starch, hydrogen peroxide, malonic acid, and sulfuric acid. The reaction is very complex. Even when Briggs and Raucher first developed the reaction, its chemistry was not clearly understood. For those of you chemistry enthusiasts interested in the chemical equation, here is the complete reaction from the MIT Chemistry Department:briggs

The Rubens’ Tube

rubensThe last demonstration is called a Rubens’ Tube, named after Heinrich Rubens who demonstrated the device in 1905. A Rubens’ Tube is simply a long metal tube with holes drilled in it a regular lengths. In this case, I drilled 1/16th inch holes spaced 1/2 inch apart, which seems to bring the best results. They can be hand drilled, however I used a milling machine for better accuracy. One end is capped and sealed and the other has a speaker attached. Thin nitrile material seals the end to avoid gas from escaping through the speaker.

IMG_4540As sound travels through the tube, sound waves create peaks and valleys (nodes and antinodes) which change the gas pressure and then affects the size of the flame. A single, even tone can create a great visualization of the sound wave.

The six-tube Rubens’ tube demonstration was created by Michael Dewberry, an amazing fire sculptor with whom I share some shop space with outside of Boston. The size of each tube favors a different frequency allowing the tubes to literally react independently to the same sounds.  The effect is mesmerizing.

Hope you liked the demos! Never stop exploring!

Total Lunar Eclipse – September 27th

lunar eclipse 2015WHEN: September 27th, 2015

  • Noticeably starts to dim at 9:07 pm Eastern US Time
  • Full eclipse begins at 10:11 pm Eastern US Time
  • Maximum Eclipse is at 10:47 pm Eastern US time
  • Main eclipse event is over at 12:27 am Eastern US Time
  • The eclipse event is plus or minus a few minutes of these times, based on your location.


All of North and South America will be able to witness the eclipse to some degree as well as Europe, South/East Asia, and Africa. The eastern half of the US will get to see 100% of the event while the west coast will see about 60% of the event. (see map)


During a TOTAL LUNAR ECLIPSE, the Sun, Earth, and Moon all line-up just right causing the earth’s shadow to cross over the surface of the moon. This blocks all the sunlight that usually lights up the moon, causing it to darken in the night sky.  The moon turns a dark orange/red color due to the bending of the light as it passes through the Earth’s atmosphere. This is the same phenomenon that gives us orange sunsets.

The September 27th Lunar eclipse is also a “Super-Moon.” This means the moon is closest to the earth in its orbit and appears larger than usual. A Super-Moon Lunar Eclipse has only occurred 5 times since 1900. If you miss it this year the next opportunity to see a Super-Moon lunar eclipse is not until 2033.


Did you know?

  • In ancient China, it was once believed that a dragon was swallowing the moon during a lunar eclipse.
  • The next Total Lunar Eclipse view-able in the entire US is not until January 20th, 2019.
  • Total lunar eclipses are often called “Blood Moons” because of their reddish color.


Exploding Watermelon – High Speed Video

On a recent episode of Jimmy Kimmel (see original clip above) I used a soda bottle to demonstrate a build up of gas pressure. Typical soda bottles are under about 40-60 PSI (pounds per square inch) of pressure when they are bottled. But they are designed to withstand much more pressure – usually around 150 PSI! We decided to put the bottle to the test using liquid nitrogen.

While impressive, this demonstration will show you why you should NEVER EVER use a soda bottle for any kind of experiment involving gases under pressure. The blast is intense, damaging, and loud. We utilized several safety staff, many safety tests, and a box custom built of Lexan (virtually unbreakable) plastic. It is the same material that bulletproof windows are made from.

Because the blast happens so fast, the production brought in a high-speed camera (the Sony NEX-FS700) to shoot the demo at 700FPS.

Since the high-speed clip is brief in the YouTube show clip, here is the extended version. The flickering light is created by the camera picking up the on/off cycle of the LED lights which are usually invisible to the human eye. Enjoy.


  Extended High-Speed Footage

Build A Hovercraft You Can Ride!

 Hovercrafts are lots of fun, and a great way to demonstrate the power of moving air. Here are the instructions to build a hovercraft of your own that you can ride on. Construction time can be as little as a few hours. These plans are based on the plans we used for the hovercraft built for Jimmy Kimmel Live. (see video) To build a smaller, tabletop hover craft powered by a balloon, click HERE.

You will need:

  • 4’ X 4’ 3/4 inch plywood
  • Piece of heavy-duty tarp material 5’ X 5’
  • .25 inch machine bolt (1.5 inches long) with nut
  • 2 2-inch washers for the bolt
  • Plastic cover for a round electrical box
  • Leaf blower (cordless electric leaf blowers are great – we used a Makita BUB182Z)
  • Lawn chair (optional)
  • String
  • Pencil
  • TOOLS: (adult use only) jig saw, staple gun, drill, utility knife, sandpaper

What to do:

  1. Mark the center of the plywood by drawing lines between opposite corners.Nail a small nail into the center of the panel and use a pencil tied to a piece of string as a compass to draw a 4’ circle as shown
  2. Using a jig saw, carefully cut the circle out of the panel and sand the edges smooth and round with sandpaper.
  3. Measure the width of the leaf blower output and use a hole cutter or jig saw to cut a hole the same width. It should be about 2 feet from the center of the plywood and it should fit snug. (use duct tape around the blower if needed to tighten up the seal.)
  4. If you want to attach a seat (or anything else) to the top, now would be the time. Drill holes and attach with machine screws. Install the machine screws through the bottom, and counter-sink all screws to keep the bottom of the craft smooth.
  5. Lay the plywood on the center of the tarp and wrap the tarp over the edge. Staple the tarp onto the top of the hovercraft with a staple gun along the edge so that the staples almost touch each other. Be sure to keep the tarp as taught as possible while stapling. When finished, you can trim any extra tarp material away with scissors if desired.
  6. Drill a 1/4 inch hole through the center of the plywood/tarp and also through the center of the electrical box cover.
  7. Feed the bolt through a washer and the plastic cover, and then up through the hovercraft. Secure with a washer and the nut from the top as shown. Cover the screw head with duct tape to avoid scratching the floor.
  8. Use a utility knife or hobby knife to carefully cut 6 evenly spaced holes into the tarp material in a circle about 10 inches from the center. The holes should be about 1.5 inches wide. (You can use an American quarter to trace the circles.)
  9. To make bumpers, you can cut foam pipe insulation and attach to the outside edge with hot glue. For extra style when using at night or indoors, add 12 volt LED strip lights and power with a 9 volt battery.Construction is complete, you are ready to hover!

Using your hovercraft:
Center yourself on the top of the hovercraft (either in the chair or sitting on the platform if you don’t have a chair) Power up the blower and have someone give you a push. You’re off and hovering on air!

Your hovercraft works best on smooth surfaces such as hard floors, concrete, or smooth asphalt. Using the hovercraft on bumpy surface can affect performance or, even worse, it could end up ripping the tarp.

Hovercrafts do not have brakes or steering! Use away from objects, people, pets, or traffic that you might run into. Be sure to wear a helmet and have someone standing by to help guide your hovercraft. Leaf blowers can also be loud, so ear protection is recommended.

Giving your hovercraft propulsion is necessary, but it allows the rider to move the craft on its own, and sort of provides some directional control. On Jimmy Kimmel Live we used CO2 fire extinguishers specially modified by a special effects company. Modifying a fire extinguisher is quite dangerous and should not be attempted. However, an unmodified CO2 extinguisher will often work (although CO2 extinguishers can be an expensive.) An easier way to get thrust is to simply use an additional leaf blower for propulsion. Be sure to point it in the opposite direction that you want to go.

Hover Science
How does your hovercraft work? Air can have tremendous lift. In fact, moving air is what allows large planes to get off the ground. When you power on the blower, it forces air out the holes of the tarp and towards the edge of the hovercraft. While you might think it would be difficult for a small blower to lift over 100 pounds, it is not. Since the large volume of moving air is spread out over a relatively thin area, it has a surprising amount of lift. The layer of air greatly reduces friction allowing you to glide on a cushion of air.

Download a PDF of these instructions by clicking HERE.

Happy Hovering!

Pringles Can Rocket Fuel

This is by far the best way to serve a can of Pringles. Inside of most large rockets is a supply of hydrogen and oxygen. When the mix of the two is just right, it creates an explosion with a huge amount of energy. In rockets, this energy get the rocket into space. In our little demonstration here, it gets the Pringles can to the ceiling.

Pringles Rocket

Here’s how it works:

  • There is a small hole in the top (really the bottom) of the can
  • Hydrogen is pumped into the cans from the bottom of the can.
  • Once the flame is lit, the hydrogen burns and air (with oxygen) enters from the bottom hole.
  • When the mix is just right, off goes the rocket and it’s time for a snack.

Barking Dog Fire Reaction

This impressive reaction is sometimes called, “The Barking Dog.” Watch the video and you’ll see why. It combines a very flammable chemical called Carbon Di-sulfate and the gas Nitrous Oxide. Nitrous Oxide is often used in race cars to give the car a sudden burst of oxygen energy. As the fire travels down the test tube it creates pressure which increases the energy released. After the reaction is over, you can see that the inside of the test tube is covered with a yellow-white sulfur powder left over from the carbon Di-sulfate.