Education and
Public Engagement
at the Lunar and Planetary Institute
Explore! Mars: Inside and Out

The Icing on the Plate - Why are the Volcanos on Mars so Tall?


The Icing on the Plate is a 20 to 30 minute activity in which older children, ages 10 to 13, create models with cake icing to compare the volcanos formed on planets with stationary surfaces and planets with moving plates. Children gain an understanding of why volcanos on Mars are so large compared to those on Earth, and what the patterns of Earth's volcanos tell us.

What's the Point?


For each child:

For each team of 3 to 4 children:

For the Facilitator:



1. Introduce the activity by revisiting what the children know about Mars and Earth volcanos.

2. Explain to the children they will create another model to demonstrate why Olympus Mons is the tallest volcano in the solar system. They are going to create and compare models of volcanos that form on planets that have plates on their surfaces that move, and on planets that have stationary surfaces, with no plates.

3. Distribute the plates, glue stick, scissors, slightly sharpened pencil, and schematic to each team. Invite each team to examine the pictures.

4. Have the children glue Olympus Mons to one plate and the Hawaiian Islands to the other plate. They may need to "round out" the edges with the scissors to get them to fit. The images should be pressed and smoothed flat onto the plates. With the slightly sharpened pencil, have the children carefully poke large, open, holes into the plates where each volcano occurs (you may wish to assist younger children with making the holes). These holes represent the calderas, the opening in the volcano where lava pours out.

5. Provide each group with a bag of icing and invite the children to create models of Mars and Earth volcanos! The icing in the bag is going to be placed under the plates and squirted out at each volcano.

Challenge each team to figure out how to make the volcanos erupt at each volcano in the Hawaiian chain without moving the bag of magma! This is very important. How will they get the volcanos to erupt first at Kauai (the oldest volcano in the image), then Oahu, then Molokai, Maui, and finally Mauna Kea on the Big Island (the youngest, or most recently created, volcano) without moving the magma "chamber?" Allow a few minutes to share ideas before proceeding. Help guide them to the conclusion that, if the magma chamber itself cannot move, the plate above it has to!

For older children, you may want to share the actual ages of the islands. Scientists have dated many rocks from each island. There is a pattern to the ages – the islands get younger from the north west (Kauai) to the south east (Big Island).

The volcanic rocks that make up the island Kauai erupted from a volcano 5 million years ago. Rocks forming Oahu are about 3.7 to 2.6 million years old. Molokai is made of rocks about 1.9 to 1.7 million years old. Rocks on Maui are between 1.3 and 0.75 million years old, and, finally, the rocks that make up the Big Island are erupting from its volcanos, including Mauna Loa and Mauna Kea, today! This island began forming about a half a million years ago.

6. Invite the children to experiment. Have one team member hold the plate. Have another team member be the timer — they will allow 3 seconds for each "eruption." Have a third team member hold the "magma chamber" (the bag with icing). Caution: Keep the icing bag twisted closed so the magma is forced out of the top of the chamber and not onto the floor!

From under the plate, have the team member with the "magma chamber" push the tip up through the hole in the Kauai volcano — the oldest in the Hawaiian Island Chain. The tip itself can be used to enlarge the hole (the tip should extend slightly higher than the plate's surface). When the timer says "go," they should squeeze the icing out of the bag, through the hole, and onto the plate until the timer says "stop" 3 seconds later. The team member should then move the plate, not the magma chamber, so that the next island in the chain is over the magma chamber. Repeat the eruption process for each island.

7. Review with the group what they learned about the formation of the Hawaiian volcanos.

8. Next invite the children to create a model of Olympus Mons, but this time they will not move the magma chamber or the plate! In this case, have the teams hold the plate and the "magma chamber" steady and repeat the squeezing of magma onto the Martian surface until they have used all their "magma."


Compare the volcanos on Earth and Mars! Invite the children to record their ideas in their GSI Journals..