Science fairs aren’t just for older kids! If you're an elementary student, you can learn a lot and have a great time doing your own project. For grades K-3, a demonstration of scientific principles is usually okay, although many fairs require real experiments. For 4th-5th graders, a complete experiment that answers a question using the scientific method is usually required.

Before you start the experimenting part of your project, do some research about your topic and then use questions like the ones below to develop your own hypothesis - what you think will happen in your experiment, based on what you know (or want to find out) about science.

- Browse our Science Fair Supplies category for more project ideas.

Life Science Ideas: Plants and Animals

• Have you noticed how the seeds in different kinds of fruit (like an apple and an orange) look very different from each other? Try growing seeds from different fruit or vegetables that you've eaten, soaking them in water for one night and then planting them in a cup of dirt. Which seeds do you expect to grow best? After doing the experiment, which seeds really grow best? (Which seed turns into the tallest plant after a month?) Why do you think that might be?

• Lots of factors affect plant growth. Try experimenting with soil type, light, temperature, water, and more. (You might want to use Wisconsin fast plants, which will allow you to study the whole plant lifecycle in a short amount of time. 

• Does calcium really make our bones stronger? What would happen if we didn't get enough calcium?

• What's the best way to wash our hands to keep us safe from germs? Use lotion and glitter or Glo Germ gel to simulate germs.

• Have you ever watched ants carrying bits of food? What food from your kitchen do you think an ant or other insect would like best? What "bait" will probably attract the greatest number of different insect species? Can you test the effect of temperature on ants?

• Do a project to find out if temperature affects brine shrimp. Do ones in a warmer environment develop faster than ones in a colder place? Is tap water, spring water, or distilled water better for hatching the eggs?

• How does the membrane and shell of an egg help protect a baby chick?

• Test green leaves to find out what other pigments are present in them.

Chemistry Ideas: Crystals, pH, Slime, and Glue

• Design a science fair project comparing and contrasting how long it takes ice to melt at room temperature compared to a warm stovetop or the refrigerator. Try thawing frozen fruit at the same time. Does it longer or the same amount of time to warm up as the ice? What if you add salt to the ice?

• Your kitchen offers lots of chemistry ideas. How does cola or another soft drink compare in acidity with other common drinks or food? You can test acidity using pH paper. You can also use indophenol to test which fruits have the most vitamin C.

• Water is sometimes called “the Universal Solvent” because it dissolves other substances so well. How well does water dissolve salt or sugar compared to other liquids (like oil, corn syrup, or vinegar)?

• Experiment with surface tension by making bubbles. Can you make them in different shapes? Can you poke scissors through them without popping them?

• Make crystals from sugar, salt, and baking soda. How do their crystal shapes compare? Does the rate of evaporation of the crystal growing medium (water, vinegar) affect the size of the crystals? Does the rate of how fast the crystals cool down affect the size of the crystals? Do impurities (such as iodized salt versus salt that is not iodized) affect the growth of the crystals?

• What happens when saltwater from the ocean evaporates?

• Chemical energy can produce power! Try making a battery from food items. Which type of citrus fruit works best? What about vinegar?

• Experiment with polymers by using milk proteins to make homemade glue. How does homemade glue compare with glue from the store? Can you develop a way to make homemade glue stronger?

• You can also make homemade slime. Does more or less of an ingredient make the slime more stretchy? What about slippery or gooey?

• Why do apple slices turn brown? Can you stop this from happening by using lemon juice? What else could you use?

• How does yeast make bread rise? What conditions make yeast react faster or slower?

Earth Science Ideas: Weather and Dirt

• The sun causes water to evaporate into the air, where it forms clouds and comes back down as rain or snow. Can wind speed, humidity, or temperature have an effect on the rate of evaporation? (Do one of these weather experiments to find out more.)

• How good is soil at breaking things down? What can you find that is biodegradable? How can you test to see whether something is or not?

• What holds more water, sand or soil? How does this affect what kinds of plants can grow in each?

• Can you learn to predict the weather from the clouds? Try using a cloud chart to make your own forecast every day for a few weeks. How accurate was the cloud-forecast method?

• How does a thermometer work? What kind of liquid works best to show changes in temperature?

Physical Science Ideas: Force and Energy

• Can you use a magnet to find traces of iron in food, dollar bills, and other household materials? Are some magnets stronger than others?

• What type of flooring creates the most or the least friction? Try carpet, wood, tile, linoleum, etc. Younger kids might test this by rolling a ball or toy truck over different surfaces. (Or use a spring scale to measure the force of friction.) Use this to decide what kind of flooring is safest (least slippery) for someone wearing socks.

• Why does a balloon stick to the wall after you rub it against your hair? Experiment with static electricity to find out how positive and negative charges in household items interact. What causes static electricity to increase? What are some ways to decrease static electricity, and which ways work best?

• The sun gives off energy that can be used like a battery to power things. Connect a motor to a solar cell and figure out what conditions it runs best under. Do different types of artificial light (such as fluorescent and incandescent) power a solar cell better than others? What happens on a cloudy day?

• Can salt conduct electricity? What about sugar? Do a project to test the conductivity of different materials using a battery and a light bulb or a buzzer.

• Use a spectroscope to compare the spectra (which looks like a rainbow) of different types of light. Do different light sources contain different colors? How does daylight compare with a fluorescent light bulb? (Note: Never look directly at the sun!) Research to find more about the different elements that are in each light source.

• Do an experiment with density of different liquids. Which is denser, oil, corn syrup, or water? If you add all three to the same glass, which liquid will float on top of the others? Compare how well some objects (e.g., raisin, paper clip) float in each of the three substances. You can also experiment with colored water (e.g., red for hot, blue for cold) to find out whether different temperatures affect water density.