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 learning the scientific process of completing a controlled experiment, collecting data and using research to explain their findings. So, 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
Using simple household items, you will investigate the sublimation of dry ice in various water temperatures. Begin by filling a bowl with cold water and set it aside. Next, use a thermometer to measure the temperature of the water. Record this temperature in your science journal.
Slowly, start to add pieces of dry ice using the heat resistant gloves or tablespoon. Once the dry ice reacts with the water, grab your camera. Then, record your observations by taking a photograph and writing down your experimental findings. Continue to write down the results in your science journal every 15 seconds until the dry ice is gone.
As the dry ice sublimes, try to capture the experiment at various stages by taking photographs. When all the dry ice dissipates, empty the bowl. Next, repeat the activity using warm water and hot water in separate bowls. Record your observations in your science journal and take plenty of photographs. Your scientific observations should show the solid dry ice transformed to gaseous carbon dioxide.
How Soap Reacts in the Microwave
In this smelly project, you will experiment the heat expansion of Ivory bar soap. Next, you will compare your results with various brands of bar soaps. First, investigate how the soaps float on water. Place the Ivory bar soap in a large bowl of water.
Then, record your observations. After writing your results and taking photographs, repeat for the two other brand bar soap. What do you observe? Did the Ivory bar soap sink or float? How did it compare to the other brands?
Once you observe the difference in densities, place the bar soaps on separate microwave-safe paper plates. Next, put the Ivory bar soap plate in the microwave. Set the timer for 2 minutes at the medium setting. Then, check the plate every 30 seconds. Gently open the microwave and observe the bar soap.
Quickly jot down your results in your science journal and take a photograph. After you complete the Ivory bar soap activity, continue with the other brand bar soaps. Then, record your observations in your science journal and take photographs of the different stages of soaps.
- ['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.