In this project, you'll do an experiment to explore the science behind a mystery that puzzled scientists for years. Read on to play the part of a NASA scientist and learn about what's creating bright areas on the dwarf planet Ceres and the process that led to a discovery on Mars.

Side-by-side images showing a dried table salt solution and a close-up view of salt deposits on the dwarf planet Ceres

Credit: NASA/JPL-Caltech | + Expand image


A rocky world covered with craters and bright spots appears brown with splotches of white and purple, the most intense of which is in a large central crater.

1. Learn about Ceres

Ceres is the largest object in the asteroid belt between Mars and Jupiter. Even though it’s in the asteroid belt, Ceres is so much bigger and so different from its asteroid neighbors that scientists classified it as a dwarf planet in 2006.

For many years, when scientists looked at Ceres through a telescope, they noticed bright regions on the dwarf planet. But how those bright regions got there remained a mystery. In 2015, NASA's Dawn spacecraft began orbiting Ceres and observing its surface in more detail. The Dawn spacecraft's close-up view allowed scientists to gain a better understanding of how the hundreds of bright regions came to be.

In this project, you'll do your own experiment to find out what's behind the bright areas on the dwarf planet Ceres.

About the image: This image of Ceres was created with data captured by NASA's Dawn spacecraft. The colors have been enhanced to reveal features on the surface of the dwarf planet. Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA | + Expand image

Side-by-side images show a person adding salt to water and stirring it to dissolve the salt.

2. Dissolve salts

Create two or three different saline, or salty, solutions by dissolving salt in warm water. You can use different amounts of the same type of salt or different types of salt to make your solutions using the ratios below.

Table salt and epsom salt ratios:
1:4 (1.0 Tbsp salt to 0.25 cup water)
1:8 (1.5 tsp salt to 0.25 cup water)
1:16 (0.75 tsp salt to 0.25 cup water)

Baking soda ratios:
1:12 (1.0 tsp baking soda to 0.25 cup water)
1:16 (0.75 tsp baking soda to 0.25 cup water)
1:24 (0.5 tsp baking soda to 0.25 cup water)

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3. Make predictions

In the next step, you will place a few drops of each solution in a dish and leave the solutions out to dry.

Before you do that, predict what you think will happen when the solutions dry. Draw or write out your predictions on the observation worksheet or a piece of paper. Be sure to think about what you might observe using different types of salt or different amounts of the same salt.

Side-by-side images show a person using a pipette to remove some of the salt solution and putting it in a Petri dish.

4. Dry your solutions

Use a pipet, eye dropper or measuring spoon to place 5 ml (about 1 tsp) of each solution into the petri dishes or plastic lids. Now wait for the solutions to dry.

Be sure to allow enough time for the solutions to dry completely. This process can be sped up by placing the dishes in direct sunlight or near another source of heat. Do not place the dishes so close to a heat source that they melt!

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Three images showing examples of dried solutions.

5. Make observations

Once your solutions have dried, look carefully at each dish. You may need to place them on a dark surface, such as dark paper or fabric. Look at the dishes close up and from an arm’s length. If you have a hand lens or magnifying glass, use that to make even closer observations. Hold the solutions in the light or shine a flashlight on them to see if that affects their appearance.

Draw or write a description of what you observe on the same observation sheet or piece of paper.

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6. Explain and expand

Below your predictions and observations, try to explain what you observed. How was your prediction different from or the same as your observation? Can you explain any differences you see between the solutions? Can you think of any places on Earth where this phenomenon might be happening? Do you think this could have happened in other places around the solar system?

7. Solutions in space

NASA's Dawn spacecraft captured pictures of Ceres in visible and infrared wavelengths, which were combined to create this false-color view of a region of Occator Crater. Credit: NASA/JPL-Caltech | Watch on YouTube

Read more about the dwarf planet Ceres and how mysterious white regions puzzled scientists at the links below. Then read about how the discovery of evaporated minerals on Mars helped scientists get a better understanding of when liquid water existed on the Red Planet.

How does your experiment compare to what scientists observed on Ceres and Mars?