Good Science Fair Projects for Fifth-Graders

by Jennifer VanBuren

It is easy to get excited about science fair projects when the experiment seems more like play than work. What lively fifth-grader doesn't love dry ice vapor cascading across the table and soap that grows into a gigantic puff? Fifth-graders are just beginning the scientific process of completing a controlled experiment, collecting data and using research to explain their findings, so it is best to keep the projects simple and engaging. These two experiments can be done in one day, have results that are impossible to miss, and demonstrate scientific processes that are familiar to fifth-graders -- sublimation and the expansion due to heat.

Effect of Temperature on the Sublimation of Dry Ice

Fill the bowl with cold water. Measure temperature.

Add a piece of dry ice, big enough to fit in a tablespoon.

Take a photo, and write observations every 15 seconds until the dry ice is gone -- sublimated into gaseous carbon dioxide.

Empty the bowl and repeat steps 1 through 3, using warm and then hot water. Capture the difference in the speed of the sublimation and the amount of vapor formed by taking photos and recording observations in your research notebook.

How Soap Reacts in the Microwave

Ivory soap floats because of air bubbles inside.

Gather background information: In addition to the written research you will do on the topic before you begin your experiment, you can also do a pre-experiment demonstration, showing that Ivory soap floats while other brands do not. Place a bar of Ivory soap and two other brands of soap into a large bowl of water. Take a photo and record observations in your research notebook.

Place one bar of Ivory soap on a paper plate or microwave safe plate and place in microwave.

Microwave for two minutes, stopping every 30 seconds to open microwave and take a quick photo before restarting the microwave.

Impress the judges: Research how a microwave works.

Repeat steps 1 and 2, using two other brands of soap.

Items you will need

  • Experiment 1:
  • Large clear bowl -- salad bowls from a discount store work great
  • Thermometer
  • Tablespoon
  • Dry ice
  • Cold water
  • Warm water
  • Hot water
  • Camera
  • Timer
  • Temperature resistant gloves or pot holder
  • Research notebook and writing utensil
  • Optional: dish soap and food coloring
  • Experiment 2:
  • 2 Ivory soap bars
  • 2 bars each of two other brands of soap
  • Temperature resistant gloves or pot holder
  • Microwave safe plate or paper plates


  • Dry Ice is frozen carbon dioxide. When it hits the water, it turns directly into a gas -- sublimation -- which is more dense than air, so it should overflow the bowl and sink.
  • Make two copies of your photos, one for the display board and one for data in your report.
  • Ivory soap has air bubbles whipped in; this is why it floats. It is also why it expands so much. The air inside is heated and expands. The other soaps have very few air bubbles, which is why they do not puff up like the Ivory soap.
  • The soap goes through a physical change, which means the soap is still "soapy" and can be used in the tub or shower.
  • Optional extensions for dry ice experiment: Put a few drops of dish soap into the water before adding the dry ice and enjoy the bubbles. Add food coloring for a cool effect.


  • Both experiments require adult supervision.
  • Protect the surface where you are doing the dry ice experiment. The bowl will get very cold, and there is a chance of spills.
  • Dry ice is extremely cold! Use gloves when handling.
  • Make sure you have good ventilation. You will not be harmed by breathing in some of the vapor, but be sure to have air circulating.
  • The soap will not damage your microwave, but it will leave it smelling wonderful! The smell will dissipate within 20 minutes.

About the Author

With degrees in biology and education, Jennifer VanBuren now utilizes her research and instructional skills as a writer. She has served as educational columnist for "Austin Family Magazine" for four years and also reports on area businesses for "Faces and Places" magazine.

Photo Credits

  • Jupiterimages/ Images