Science Experiments for Kids: Siphon Water Coaster

One of the most popular water based science experiments for kids in recent years is a water wall; take the fun a step further by creating a siphon water coaster! This project will introduce your kids to the concept of siphons and atmospheric pressure. It’s also is a great activity for a hot summer day.

We made two versions of thee siphon, one where we siphoned directly from top of the upper jug and  one where we poked a hole near the bottom of the upper jug and sealed it with clay. Both versions work and are shown in the video. The instructions below are for the first version. The only benefit of poking a hole in the upper jug is that the siphon is a little easier to start using the bulb syringe. The downside is that it leaks!

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Science Experiments for Kids: Siphon Water Coaster



  • Step One Prepare your upper water container. Take one of your gallon jugs and cut off the top to make it easy to refill. Now poke two holes near the top to use to hang it on the fence.  Place a zip tie through each of the top holes and secure the jug in place on the fence  (it will be heavy when filled with water). This will be your starting point.
  • Step Two Place one end of the tubing into the top jug. Make sure the end of the tubing is touching the bottom of the jug interior. Fill jug with water and add food coloring. Add some fine gravel to the bottom of the jug.

Science Experiments for Kids: Siphon Water Coaster

  • Step Three Start securing the tubing to the fence in a slight downward position to create a “roller coaster” look. Add zip ties to hold the tubing in place. You can create a loop BUT loops are harder to suction using a bulb syringe (see tips section). Make sure that end of the tubing is lower than the tubing start point. Add a gallon jug at the end of the tubing to catch the siphoned water. Have a 2nd jug nearby to use when transferring water back up to the start point. Keep the tubing end loose enough to be able to lift it higher than the tubing start to stop the siphon.
  • Step Four Squeeze your bulb syringe and hold it in the squeezed position while you insert it into the end of the tubing. When you are ready to start your siphon release the syringe. The suction should pull the water through the tubing. Try again if it doesn’t work at first. Remove the bulb syringe and position the end of the tubing to dump into the jug at the siphon end. Your siphon should be flowing!

Science Experiments for Kids: Siphon Water Coaster

  • Step Five Continue adding water to the top container to keep the siphon flowing. Suck up the fine gravel and watch it move through the tubing!  Recycle the water by switching out the bottom jugs and refilling the top jug as necessary. To stop the siphon lift the end of the tubing higher than the start point. Viola! It stops.


  • Don’t make the upward climb too high or too loopy. The bulb syringe will not be able to create enough suction to pull water through a super steep incline. If you decide to create a more complex siphon with lots of climbs and loops it can still work but you will have to use lungpower to suck it through the tube to get the siphon started. You will also get a mouthful of water!
  • Don’t put the zip ties too tightly around the tubing or you will restrict water flow.
  • Do make sure there are no kinks in your tubing that will restrict water flow.
  • If you have a vertical fence like ours you can adjust the tubing up and down to fine-tune the siphon.
  • Do make sure the siphon end is below the start point. That is the number one rule of siphons!
  • Use sprinkles instead of gravel, however, be aware that sprinkles lose color and dissolve in water so they will make the water gray and a little oily.
  • Dump the water in plants at the end of the project!

Looks Like

WET Design. WET Design is a design company that creates masterpieces with water. They have designed incredible water features for public spaces around the world. If you have ever seen the dancing water fountain in front of the Bellagio in Las Vegas you have seen their incredible work in action. Our siphon coaster is a simple science project that gets kids thinking about the possibilities of working/playing/creating with water.


Hands down this is THE hardest project I have ever had to photograph. It’s not the prettiest sight you’ll ever see and the project goes quick BUT it is a lot of fun! Watching the gravel zip through the plastic tubing is a great demonstration of just how quickly water can move. Siphons are also one of those great scientific phenomenon that feel a little magical. My son loved watching the water and gravel move back and forth with the air pressure created by the suctioning.

Science Experiments for Kids: Siphon Water Coaster

If you liked this science project you might want to check out Building and Destroying Toothpick Structures. If you are interested in more water play for a hot summer day make a Sand River.

After this you might want to go forth and make thee a water wall! There are so many fabulous ideas for water walls on the web. Here are a few to start with:

And if your child loves working with water or just splashing and playing with water you should probably own one of theseI’m finally getting one this summer!

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