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Science Rocks!

Chain Reaction Machine


your results

Sent in by:
Horace Mann School of Newton, MA

The rubber wheel connects to the dominoes, the dominoes connect to the mouse trap...

Materials Needed

  • Different things from around your house.
  • What you can't use is plug-in electricity or more than one cup of water.
  • 1 2-foot long piece of 2x4 (for the top of your wood frame)
  • 2 3-foot pieces of 2x4 (for the sides of your wood frame)
  • 1 2-foot by 3-foot piece of plywood (for the base of your frame)
  • deck screws
  • screw driver (an electric one works best)
  • brackets (angle brackets and brackets for copper tubing) for attaching different parts of your link to the frame
  • staple gun



  1. A Chain Reaction Machine uses natural forces, like gravity and elasticity, to make something happen. The chain is a series of simple devices like a pulley or some dominoes that knock into each other. The idea is to put together a few of these devices so that they go off one right after the other, like a chain reaction. Once you put the first one in motion, the rest of the machine should go by itself.
  2. Check with a grown-up before you begin. You will need an adult to help you build a frame for your link in the Chain Reaction Machine. Make sure it's okay to use the objects you choose for your Chain Reaction Machine.
  3. The ZOOMers used different types of string, rubber wheels, a drinking glass, fishing weights, springs, marbles, dominoes, magnets, mousetraps, different kinds of balls (metal ones, too), soda bottles, pulleys, levers, small battery-operated vehicles, electrical wire and wire clips, a small battery-operated fan, toys, balloons, helium, measuring sticks, cans, fishing line, straws, vinegar and baking soda, corks, baggies, cardboard, glue, feathers, glitter, plastic and paper cups, construction paper and tape. Basically you can use just about everything, even the kitchen sink.
  4. Each link in your machine must begin and end with the pull of a string. This way when you finish building your links, you can connect them with string. The action of one link will make the action of the next link begin.
  5. Decide how many links you want in your Chain Reaction Machine. You will build each link inside a frame. The frame makes the link stable and you can attach different parts of your link to it. If you use wood to build your frames, have an adult help you. If you don't want to build wood frames, use something freestanding, like an ironing board. Ironing boards are just about the right size for a frame, and the top usually has holes that you can use to attach wires, string, hooks, and paper clips. Just be sure to ask if it is okay to use it.
  6. To build a frame out of wood, have an adult screw the pieces of 2x4 together into a U-shape no larger than four feet tall and two feet wide. Screw the 2x4 U to the plywood base so that the 2-foot 2x4 piece is at the top and the plywood base is at the bottom.
  7. Find some friends, split into teams (one for each link) and start designing your links.
  8. Here are some tips to keep in mind as you design: Make sure that there is enough force for the ending string of one link to pull on the starting string of the next link. Also make sure there's enough energy to keep everything in your links moving. Although you can't use plug-in electricity, you can use things like mousetraps, rolling marbles and other moving parts that gain energy when they are pulled down by gravity.
  9. Once the frame is done and you've planned your design, ask an adult to help you attach the extra pieces of wood or cardboard that will hold different parts of your link. To mount wood pieces to your frame, use angle brackets. To attach round gadgets like wood dowels, use copper tubing brackets. For mounting cardboard tubes and other thin items, a staple gun works best.

Let us know what worked with your design and what you had to change. When you made changes, did your Chain Reaction Machine work more smoothly? Why or why not?

Some of your Results

Luke, age 9 of Lincroft, NJ wrote:
I sorta made a game out of it. I pushed a toy car and it knocked down some dominos that went to the edge of a tabletop. The last domino was attached to a marble so when it fell it pulled the marble down. At the bottom there were three cup, one was 50 points, one was 100 points, and one was 200 points. I got 50 points.

Dillon, age 13 of Rison, AR wrote:
I pushed a car that went down a racecar track, the car fell and hit along peice of wood against a wall. The wood which fell sideways and hit a string that was connected to the ceiling and was taped to the wall, and had a ball tied to the end of it. The wood knocked the string loose which swung like a pendelum and hit dominoes on a table. The dominoes fell in a line and hit another racecar down a track from the table. The racecar hit a book that was lying against a string. The string was tied to a light switch, so when the car hit the book, the string tightened and the lights turned out.

Morgan and Tara of GA wrote:
It went up and down and hit some dominos. My dominos were special because they were very colorful! It raised a flag and filled a bucket with water It was amazing!

Kathy, age 7 of San Francisco, CA wrote:
We were building a machine and when we were done, I had to put a ball and the ball changed a color and it was kind of different looking.

Azael, age 7 of Vancouver, BC wrote:
I knocked down the dominos and yanked the string & yanked the fork made the domino fly into the trampoline and knocked down the other domino then it opened the door.

Cassie, age 12 of Madison, WI wrote:
We did a chain reaction machine in science class. In groups of 3 or 4 we had to build a baloon popper in at least 3 steps to get a C. Ours went like this: a marble went down the marble track and landed in a cup. The cup went down and knocked dominoes down, which hit a baseball. The baseball went down a ramp and hit a water bottle. The water bottle poured through a funnel and filled a cup on a string. The cup fell and hit a mousetrap and sent the balloon falling on to a cork with nails in it and popped. When we were done, we had to test it 3 times sucessfully in a row and then watched the ZOOMsci balloon popper!

Josh, age 10 of Lawn, PA wrote:
I released a small marble at the top of a ramp. It rolled into a larger marble, which rolled down another ramp and rolled into a flashlight which I had positioned with the front end on top of a yoyo whose string was looped over a raised beam with the loop on the other end around the handle of a cymbal. When the flashlight was knocked away, the yoyo shot up in the air pulled by the weight of the cymbal. The cymbal fell on one side of a metal lid, tipping it and causing the other side to rise. This dislodged a domino which fell and knocked over other dominoes creating a domino train. This was the last stage of the machine. There was one problem: I had to position the flashlight just right; if it covered too much of the yoyo, the flashlight would not move enough for the yoyo to slip free. If it did not cover enough of the yoyo, it would not put enough weight on it to keep it in place. And the yoyo would slip and the machine would activate itself.

Rylan and Noah, age 9 of Trenten, OH wrote:
When we caught the ruler between are legs it was slower then are fingers.

Michael, age 12 of Elkhorn, WI wrote:
My seventh grade class has to do this and their task is they have to blow out a Birthday candle and you have to use at least one mouse trap. My machine drops a jar on top of it and cuts of the oxegen, and as you know when a candle has no oxegen if blows out!

Jake, age 6 of Frenchtown, NJ wrote:
Well when I did it, I pulled a string which dropped a cow off a table which made a ball roll into a domino. That's all I could do because I don't have much things to do it with.

Dustin, age 9 of Poland, IN wrote:
I did this experiment with my 2nd grade class. We made it have 4 steps. We had golfballs, pulleys, and a few action figures. It had about 2-4 seconds in between each reaction. We love doing your experiments. We do them whenever we can. We hope to do another one of your experiments soon.

Amina, age 10 of Toronto, ON wrote:
What happened when I made the chain reaction machine is, well there is no other word but this. FANTASTIC! I made it in my backyard and it was huge!!! I noticed that the object I put in the beginning hit something else and that hit something else and so on. I had alot of fun doing this experiment.

Alexia, age 5 of Peabody, MA wrote:
Water poured into an upside down funnel made from a plastic soda bottle that was taped on a table leg, the water then ran through a tube into a cup that was on one side of a see saw made from a painters stick and cup. When the cup filled with water and the see saw went down, a string tied to the stick was pulled and it rolled a car into dominoes. The dominoes then knocked down and rolled a ball into a cup.

Jessica, age 13 of Tuscan, AZ wrote:
Well I realized my chain reaction machine worked out great. I recorded the time, it was 35 seconds. Is that cool or what?

Stephanie wrote:
I was wondering what your chain reaction machine looked like. If you want to do something like that and you didn't want to use time by building a frame what could you do?

Tanner, age 11 of Calgary, AB wrote:
At school I built one with 6 steps, and It was really fun, and it worked! It had a mouse trap, a light bulb, and pulley and a golfball.

Michael, age 8 of Placentia, CA wrote:
First, I rolled a big toy truck doWn a ramp. Like dominoes each toy fell over. The last toy (Garfield) hit a small disk into a boX.

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