hypothesis for 6th grade science project

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6th Grade Science Fair Projects

6th grade science fair projects can be fun as well as educational. The key to finding a good project idea is to pick one that can be completed in time, uses materials you can actually find, and incorporates the scientific method . You can turn any science project into a science fair project by finding one factor you can change (the independent variable ) and measuring its effect on another factor (the dependent variable ). Either predict what you expect to happen or form a hypothesis , record the data, determine whether it upholds the prediction, and report your findings.

Here is a collection of 6th grade science fair project ideas. The projects include chemistry, biology, physics, geology, weather, environmental science, and engineering.

Grow Geodes in Egg Shells

Geodes form when minerals crystallize from water trickling into holes within rocks. While natural geodes take millions of years to form, you can make your own geode in a few hours or days. Use an eggshell as your “rock” and crystallize salt, sugar, borax, or Epsom salts.

Make It an Experiment: Turn this cool project into a science fair experiment by predicting how temperature affects crystal formation. You can explore the effect of rate of cooling on crystallization by insulating the growing geode with a hot water bath, leaving it at room temperature, and refrigerating it.

Build a Structure to Withstand an Earthquake

Explore the principle engineers use to construct buildings to withstand seismic events like earthquakes. Use styrofoam plates as the “ground” and make buildings using craft sticks. Join the craft sticks to each other using mini-marshmallows. Use a sharp pencil to poke holes in the bottom of the plate to insert craft stick supports. These will be the building’s foundation. When you have finished construction, shake the plate from side to side to simulate an earthquake.

Make It an Experiment: What type of structure survives the simulate earthquake the best? Is it rigid or flexible. You can perform a similar simulation by constructing a structure meant to withstand a hurricane. Use a fan as the wind and examine how the type of wall affects the building’s stability.

Control the Rate of a Color Change Reaction

Many color change chemical reaction are clock reactions. What this means is that if you mix the same amounts of chemicals under the same conditions, the color change occurs after the same time interval (like clockwork). The blue bottle reaction and vanishing valentine are excellent clock reactions for 6th grade science projects.

Make It an Experiment: Predict whether changing the concentration of the starting chemicals or the temperature of the liquids will increase or decrease the speed of the color change. Perform the experiment, record the results, and see if you can explain them.

Turn Milk Into Plastic

Many common plastics come from petroleum, but you can make a plastic from milk . Basically, all you do is curdle the milk . Heat 1/2 cup of milk or heavy cream over low to medium heat until it simmers. Stir in lemon juice or vinegar until the mixture starts to thicken. Remove the pot from heat. When the liquid has cooled, rinse the curds with water. These curds are a natural casein polymer. You’ve made homemade plastic!

Make It a Science Experiment: Your experiment might explore the properties of this plastic, including how far it will stretch, how much weight it can hold, and whether it can be used as a modeling compound. Another option is to compare the amount of plastic you get from cow’s milk compared to goat milk or sheep milk. Do you get the same amount of plastic from cream as from milk?

Explore the Pigments in Leaves

Most leaves look green from chlorophyll, but actually contain several different pigments. In the autumn, plants make less chlorophyll, so you can see the other colors. You can use paper chromatography to see pigments in leaves. To do this, grind leaves to break open their cells (a blender works well), place them in a small jar, add just enough alcohol to cover the leaves, and insert a long strip of coffee filter paper into the jar. You want one end of the paper strip in the leaf mixture and the other end extending up and outside of the jar. As liquid moves up the paper, it pulls pigment molecules along. Smaller molecules move faster, while larger molecules move slower. Over time, this separates the colors.

Make It an Experiment: See if you can identify which pigments the leaves contain based on their colors. Gather leaves from a single plant from multiple seasons. Compare the pigments from spring, summer, and autumn. Can you tell the season by the pigments present in the leaves?

See the Iron in Breakfast Cereal

Use a magnet to separate the iron from breakfast cereal so you can actually see it. To do this, pour one cup of crushed cereal into a zipper-lock bag and fill the bag half full of warm water. Shake the bag to mix the contents and allow at least 20 minutes for the flakes to dissolve. Place a strong magnet against the side of the bag and slosh the contents around so the magnet can capture the iron. Finally, keep the magnet up against the side of the bag but tilt the bag so you can see the iron. It will appear as tiny black specks.

Make It an Experiment: Compare the iron in different cereals. Do all cereals contain about the same amount of iron? Does it look the same in every product?

Use Eggs to See Which Drinks Stain Teeth

Tooth enamel is the mineral hydroxyapatite (hydrated calcium phosphate), while egg shell is calcium carbonate. Egg shell is more porous than tooth enamel, so it stains more quickly. Soak eggs in tea, coffee, soda, and other liquids to determine which ones stain teeth. Common drinks also contain acids in addition to pigments, so some drinks dissolve egg shell (and teeth). Can you identify them?

Make It an Experiment: After staining the eggs, predict which methods work to remove the stains. Test these methods and see if you can discover how they work.

Use Household Chemicals to Clean Old Coins

Learn about oxidation, which includes tarnish, patina, and rust. Explore the cleaning power of common household chemicals. Soak discolored coins in soap, laundry detergent, lemon juice, salt water, soda, ketchup, vinegar, salsa, or any other products you like. After soaking, remove the coins and rinse them to see which ones clean the coins the best.

Make It an Experiment: Part of making this project an experiment is predicting which chemicals make the best cleaners. Also, you’ll have to determine the best amount of time to soak the coins. You can compare how well these chemicals work on different types of coins (like pennies, quarters, and nickels). Do you think the metal composition of the coin affects how well the cleaners work?

Make a Graphite Circuit

Graphite is a form of carbon that conducts electricity. You can draw a line of graphite using a pencil to make a simple circuit . Use a battery with both terminals on top (like a 9V). Turn the battery upside down on the paper and draw heavy pencil lines whether the terminal rest (don’t connect these lines!). Take an LED and bend the wires apart so they can rest separate on the paper. Rest each wire on a pencil dot. Complete the circuit by drawing lines to connect one terminal of the battery to one end of the LED light and the other end of the battery to the other LED wire.

Make It an Experiment: Explore whether the length or thickness of the line affects how brightly the LED glows. You can make a circuit using aluminum foil strips instead of graphite, too.

See Whether Food Color Affects Its Flavor

Examine the effect of color on perceived taste by coloring different drinks with food coloring and asking subjects to describe their flavor.

Make It an Experiment: Compare the flavor of colored and uncolored versions of the same drinks. Start with drinks that don’t have any color so subjects are less likely to guess the drink flavor in advance.

Test Whether Temperature Affects Maximum Balloon Size

Start with a package of party balloons (ideally all the same color and brand). Part of the fun of this science fair project is planning how you can test the effect of temperature on balloon size. Consider your options in terms of indoor versus outdoor weather and access to freezers and saunas. You need to blow up a balloon and measure its maximum size before it pops. Either get a friend to help with the measurement or fix a measuring tape to the wall and keep an eye on the numbers.

Make It an Experiment: You are well on your way to making an experiment if you make a prediction about whether temperature affects maximum balloon size and design a method to test the hypothesis. Can you propose an explanation for your results?

See If All Crayon Colors Melt at the Same Temperature

Crayons consist of wax, colorants, and sometimes fillers. See whether all crayons melt at the same temperature. You’ll need a bunch of different colors of crayons, a thermometer, and a way to melt them. Fortunately, wax melts at a lower temperature than water boils, so you can slowly heat water, watch for melting, and record the temperature. Another method is to place crayons (not-touching) on a sheet of wax paper on a cookie sheet, heat an oven to 350 ºF (or any temperature, really), and record which crayons melt first.

Make It an Experiment: Make predictions and answer questions. Do you get the same results with different brands of crayons? Do old crayons have the same melting point as new crayons? Watch for control variables , like the size of the crayons and whether you pre-heated the oven.

Make Lightning in Your Mouth

To make lightning in your mouth, crunch a Lifesaver Wint-O-Green or Pep-O-Mint candy in your mouth in front of a mirror in a dark room. Saliva can ruin the effect, so you might want to dry out your mouth with a paper towel first. The blue sparks that resemble lightning are due to an effect called triboluminescence . The sugar in the candy releases electrical energy when the crystals are compressed. The tiny charges attract nitrogen in the air, making miniature lightning bolts. Make It an Experiment: Get different types of hard candies and predict whether they will produce sparks in the dark. See if you can explain why some candies work better than others.

More 6th Grade Science Fair Project Ideas

Here are more ideas for projects to try:

Test which brand of gum lasts the longest. Does it matter whether it contains sugar?
What is the tallest tower you can build with 100 Legos?
What is the fastest way to cool a soda?
What metal is most resistant to corrosion by sea water?
Does the shape of an ice cube affect how quickly it melts?
Which soft drink sprays the most liquid after it is shaken?
What type of sweetener do ants prefer?
Does the color of a crayon affect how long of a line it will write?
Do different types of knots affect the breaking strength of a rope?
What type of air freshener makes a school bus smell best to the greatest number of students?
How long does it take for milk to go “bad” refrigerated and unrefrigerated?
Which apps run down a cell phone battery the fastest?