PBS KidsZOOM Home Back to Activity
Science Rocks!

Gumdrop Dome


your results

Sent in by:
Tunisia of MO

Do you think gumdrops can support a stack of books?

Materials Needed

  • a box of toothpicks
  • a large bag of gumdrops
  • books



  1. How many books do you think gumdrop domes can support?
  2. Check with a grown-up before you begin.
  3. Use five gumdrops to connect five toothpicks in a ring. This is your base.
  4. Use two toothpicks and one gumdrop to make a triangle on one side of the base. In the diagram below, each new step is highlighted in yellow.
  5. Repeat this all around the base until you have five triangles.

  1. Use toothpicks to connect the gumdrops at the tops of the triangles.

  1. Push one toothpick into each of the top gumdrops.
  2. Use one last gumdrop to connect these toothpicks at the top.

  1. How many domes do you think you will need to hold up a book?
  2. Make a hypothesis, then build as many domes as you'll need. Let your domes dry overnight. If you don't let them dry, they won't be able to support much weight.
  3. Now it's time to test out the strength of your domes. Arrange your domes, and carefully place a book on top. If your domes can support one book, then keep going. How many books can your domes support?
  4. The reason the domes can support so many books is because of their shape. A dome is shaped like an egg. An egg has two domes, one on either side. An egg can be very fragile, but it can also be very strong, depending on where you put weight on it. This is because the weight spreads out over the egg's dome shape.

A lot of domes are made up of small triangles. That's because triangles are stable shapes. That means they don't bend, twist, or collapse easily when you push on them. How can you add more triangles to your domes so they can hold more weight? Test out your design, and then send your discoveries to ZOOM.

Some of your Results

Msad Kindergarten, age 5 of MN wrote:
We made 7 domes. We piled 21 hard cover books on them.

Matthew of San Ramon, CA wrote:
I made 4 gumdrop domes from a couple weeks ago. It supported 5 books without smoshing them. Thanks Tunisia for this awesome ZOOMsci.

Kiva, age 8 of Fort Bragg, NC wrote:
What happend is that I took 11 Dots/ gummies and 17 toothpics to make my dome. I call my dome the Home Dome. I think that this was at least my second or third favorite project ive ever done.

Tina of Daleville, AL wrote:
Well when I was making my gumdrop dome it got a little harden.

Pearl, age 9 of Sydney, AU wrote:
It was fun to make and it really can hold up a book!

Kate, age 9 of Oakland, CA wrote:
well the toothpicks wasn't that helpful but it worked and it was awsome that everyone in my class loved we did it 10 times we just couldn't stop!!

Laura, age 11 of Palmdale, CA wrote:
I did this for my science fair I luv this best project ever!!!

Austin, age 10 of Orlando, FL wrote:
i tried it with fruit because I did not have gumdrops and it worked

Felice, age 8 of Pleasant Hill, CA wrote:
When I started this experiment it didn't turn out so well because I did not put the toothpicks deep enough into the gumdrops. When I did, I started making my own shapes and one of them held 9 lbs.!

Taylor, age 11 of Renton, WA wrote:
I tried this project for the science fair at my school, I built four domes, and each of them I let harden overnight. I put them all together and started stacking books. I stacked 18 paperback chapter books all about the width of 1/2 inch to 1 inch. They stayed for about 2 minutes. Then they fell.

Jordan, age 11 of King, NC wrote:
When I did the gumdrop dome with my class, I changed one thing about how the dome was made. I learned that a pentagon base dome was the strongest base for a Gumdrop Dome.

Sofia, age 8 of Philadelphia, PA wrote:
Well, I enjoyed it but I lost the first time

Shayna, age 11 of Yakima, WA wrote:
When I did it it really worked. I put 12 books on it and it held for 6 min. then fell

Bailey, age 10 of Omaha, NE wrote:
I found out that triangles are the strongest shape.

Frankie wrote:
When we did the gumbdrop dome we relised that the triangle is the most common seen on bridges. Because it is the strongest of all shapes.

Brock, age 10 of Omaha, NE wrote:
When we did what the instructions said, it worked well. But when we got the chance to create something on our own, we doubled the sides on the base. I like to say it's the superdome of the gumdrop creations.

Greg, age 10 of Omaha, NE wrote:
It worked but you need to really organize you're gumdrops.

Michael, age 10 of Omaha wrote:
We changed the base to 6 and it was a better structure.

Morgan, age 9 wrote:
I had ten book and here is the amazing part, 5 fell off and 5 stayed on!

Taylor, age 10 of Toronto, ON wrote:
It Held up 6 , 7 inch books and 2, 2inch books.

Alliyah, age 10 of Yankton, SD wrote:
I didn't think it would hold very many books but I got 20 chapter books on it. I also found it helped if you put a large bok on first to distribute the weight evenly. I suggest leaving it out an extra night so its more sturdy.

Alliyah, age 10 of Yankton, SD wrote:
It worked really well but it needed to be left out longer.

ZOOM Fans of Montegut, LA wrote:
We built 4 domes with 5 gumdrops on the bottom and 4 domes with 6 gumdrops. We found that the domes with 5 gumdrops on the bottom was stronger than with 6 gumdrops when they were separate. When we put the domes together to support books, the domes with 5 gumdrops held 6 books. The domes with 6 gumdrops held 8 books.

Lauren, age 13 of Ripley, MS wrote:
It held up 3 books.

ZOOM fan of NE wrote:
When I did 10 books it collasped on my hand.

Taylor, age 12 of Little Rock, AR wrote:
It collasped on the fifth book.

Hem, age 15 of Ahmedabad wrote:
It supported 6 books.

Omarou, age 13 of New York City, NY wrote:
We had to make differet stuff. See if triangels are better at holding stuff then squares. Triangels are better at holding stuff then squares.

Jasmine, age 12 of Bronx, NY wrote:
Some of the gum drops slited when I put it together and then when I got to the top of the dome the gum that went their broke so I had to put a new gumdrop on then one of the tooth picks broke in half when I brought it to school.

Chrystal, age 12 of Bronx wrote:
When I was building the dome I didn't think it would stand, but when I finished I found it to be very sturdy. So in order to test the strength of the dome I put books on them. The domes held up to 16 (Regular size) books. I tried to get up to 20 books but when I tried to but the 17th book on they just sort of fell ever to one side because one of the broke.

Christina, age 12 of New York, NY wrote:
I thought it was easy at first, then when I tryed it Building the dome it became a challenge. When me and my partner, Aaron, finished. Then we tryed again because the dome wasn't stable. We finally accomplished our goal to making the dome stable.

not yet implemented