Welcome! This article gives 50 easy, safe, and exciting science project ideas for class 3.
Each project uses simple materials, short steps, and a clear explanation so a third grader can do it with a teacher or adult.
At the start you’ll find tips for safety and how to present results. Each project includes: Materials, Steps, What you’ll learn, and a short Example result you can expect.
How to use these science project ideas for class 3
- Read each project and pick one that looks fun and safe.
- Ask an adult for help when you use heat, sharp objects, glass, or chemicals (even safe household chemicals).
- Write down your question (what you want to find out), the materials, the steps, and what happened.
- Take pictures or draw what you see — this helps when you share your project in class.
- Keep notes: date, time, what changed, and what stayed the same.
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Tips for a good science fair project
- Choose one clear question. (Example: “Does salt change ice melting time?”)
- Change only one thing at a time (variable). Keep everything else the same.
- Repeat the test 2–3 times and take average results.
- Make a simple chart or table to show results.
- Practice explaining your project in 1–2 minutes: what you did and what you learned.
50 Science Project Ideas for Class 3
1. Melting Race: Which Melts Fastest?
Materials: Ice cubes, salt, sugar, vegetable oil, stopwatch, plates.
Steps: Put one ice cube on four plates. Sprinkle salt on one, sugar on one, oil on one, and nothing on the last. Time how long each takes to melt.
What you’ll learn: How different substances affect melting of ice.
Example result: The salted ice melts fastest because salt lowers freezing point.
2. Homemade Volcano (Baking Soda & Vinegar)
Materials: Small bottle, baking soda, vinegar, dish soap, red food coloring, clay or paper to build volcano shape.
Steps: Put baking soda and a tiny bit of dish soap in bottle. Add food coloring. Pour vinegar to make it foam and erupt.
What you’ll learn: Acid-base reaction creates gas (carbon dioxide) that pushes the foam out.
Example result: A bubbly “lava” eruption that flows down your model volcano.
3. Plant Growth: Light vs. Dark
Materials: Two small potted plants or sprouted beans, water, paper box or dark cloth.
Steps: Keep one plant in sunlight and one covered in dark. Water both equally and watch daily for 1–2 weeks.
What you’ll learn: Plants need light to grow tall and green.
Example result: The dark plant becomes pale and tall (stretching toward light).
4. Sink or Float: How Objects Behave
Materials: Large bowl of water, coin, plastic toy, leaf, stone, pencil.
Steps: Predict which items will sink or float, then drop them in water and observe.
What you’ll learn: Some materials float because of density or trapped air.
Example result: A plastic toy floats; a stone sinks.
5. Rainbow in a Glass (Liquid Density Column)
Materials: Honey, dish soap, water, vegetable oil, rubbing alcohol, food coloring, clear glass.
Steps: Color different liquids and carefully pour them in order of density into a glass to form layers.
What you’ll learn: Liquids have different densities and can form layers.
Example result: A colorful layered column like a rainbow.
6. Static Electricity with Balloon
Materials: Balloon, small bits of paper, wool cloth, hair.
Steps: Rub balloon on hair or wool and hold near small paper bits — they stick.
What you’ll learn: Rubbing transfers electrical charge (static) that attracts light objects.
Example result: Bits of paper jump toward and stick to the balloon.
7. Invisible Ink (Lemon Juice)
Materials: Lemon juice, cotton swab, paper, lamp or iron (adult help).
Steps: Use lemon juice as ink to write on paper. When dry, heat gently to reveal message.
What you’ll learn: Heat causes lemon juice to brown and appear.
Example result: Hidden words appear brown when warmed carefully by an adult.
8. Make a Compass (Magnet & Needle)
Materials: Sewing needle, small bar magnet, cork, bowl of water.
Steps: Magnetize needle by stroking with magnet, push into cork, float on water; needle points north-south.
What you’ll learn: Magnets align with Earth’s magnetic field.
Example result: Needle points roughly north-south showing a simple compass works.
9. Chromatography Art (Separating Colors)
Materials: Coffee filter or paper towel, markers (water-based), cup of water.
Steps: Draw a dot near edge of paper, dip edge in water, watch colors separate as water rises.
What you’ll learn: Many marker inks are mixtures of different dyes.
Example result: A colorful ring showing red marker splits into orange, yellow, etc.
10. Grow Crystals (Salt or Sugar)
Materials: Hot water, salt or sugar, string or stick, jar.
Steps: Make very salty or sugary hot water, tie string to stick, suspend in jar and wait for crystals to form.
What you’ll learn: When solution cools, dissolved solids come out and make crystals.
Example result: Sparkly crystals form on the string after a few days.
11. Lemon Battery (Electricity from Fruit)
Materials: Lemon, copper coin or wire, zinc nail, small LED (low voltage), wires.
Steps: Insert copper and zinc into lemon, connect wires to LED—may glow faintly.
What you’ll learn: Chemical reactions can make small electric current.
Example result: LED may glow dimly showing lemon made small electricity.
12. Make a Rain Gauge (Measure Rainfall)
Materials: Clear plastic bottle, ruler, marker.
Steps: Cut bottle top, invert to make funnel, mark measurements, place outside and record rainfall after a rain.
What you’ll learn: How scientists measure weather data like rainfall.
Example result: A reading shows how many millimeters or centimeters of rain fell.
13. Floating Egg (Salt Water Density)
Materials: Egg, glass of plain water, cup of salty water (add lots of salt).
Steps: Put egg in plain water (it sinks). Put egg in salty water (it floats).
What you’ll learn: Salt increases water density and helps egg float.
Example result: Egg floats in salty water like a mini Dead Sea.
14. Simple Circuit with Bulb
Materials: Small bulb, battery, wires, tape.
Steps: Connect battery to bulb with wires — bulb lights when circuit is closed.
What you’ll learn: Electricity flows in a loop (circuit) and lights a bulb.
Example result: Bulb lights when wires connect both ends of battery.
15. Color Changing Milk (Soap & Surface Tension)
Materials: Plate, milk, food coloring, dish soap, cotton swab.
Steps: Put milk in plate, add drops of food coloring, touch soap-soaked swab to center — colors swirl.
What you’ll learn: Soap breaks surface tension and interacts with fat in milk to move colors.
Example result: A swirling, colorful pattern appears quickly.
16. Make Slime (Polymers)
Materials: Glue, baking soda, contact lens solution (or borax solution), bowl.
Steps: Mix glue and baking soda, add contact lens solution until slime forms.
What you’ll learn: Polymers are long chains that change when mixed with certain substances.
Example result: Stretchy, squishy slime you can play with.
(Adult supervision needed for chemical ingredients.)
17. Paper Airplane Forces (Lift & Drag)
Materials: Paper, tape, ruler.
Steps: Fold different airplane designs and measure how far they fly. Change wing shape and test again.
What you’ll learn: Wing shape affects flight distance because of lift and drag.
Example result: One design flies farther, showing how shape matters.
18. Make a Periscope (Light Reflection)
Materials: Toilet paper tubes or long cardboard, two small mirrors, tape.
Steps: Put mirrors at 45° angles at each end so you can see over an obstacle.
What you’ll learn: Light reflects off mirrors to change direction.
Example result: You can see over a box using your homemade periscope.
19. Baking Soda Rocket (Bottle Rocket)
Materials: Small plastic bottle, baking soda, vinegar, cork or balloon, tray, outdoor space, adult help.
Steps: Put vinegar in bottle, put baking soda in paper, quickly drop it in and close — stand back as it shoots.
What you’ll learn: Rapid gas production creates pressure and launches the bottle.
Example result: Bottle pops off like a tiny rocket (always outdoors and supervised).
20. Shadow Play (Sun & Light)
Materials: Toy figures, flashlight or sunlight, white paper.
Steps: Place toys in sunlight or shine a flashlight to make shadows and move them to see how shape and size change.
What you’ll learn: Light source angle changes the size and sharpness of shadows.
Example result: Long morning shadows and short midday shadows demonstrate light angle.
21. Erosion in a Tray (Water & Soil)
Materials: Tray, sand or soil, spoon, watering can.
Steps: Build small slopes of soil, pour water gently from top and watch how soil moves.
What you’ll learn: Water moves soil (erosion) and creates small channels.
Example result: Tiny gullies form where water flowed, showing erosion.
22. Make a Simple Thermometer
Materials: Clear plastic bottle, straw, clay, colored water.
Steps: Put colored water in bottle, seal with clay around a straw leaving straw open at top. When heated, liquid rises in straw.
What you’ll learn: Heat makes liquids expand so level rises; basic thermometer principle.
Example result: Water level moves up when placed in warm sun.
23. Sound Vibrations (Rubber Band Guitar)
Materials: Empty tissue box, rubber bands of different sizes.
Steps: Stretch bands across box and pluck — different bands make different sounds.
What you’ll learn: Pitch changes with band thickness and tension — vibrations make sound.
Example result: Thin tight band makes high sound; thick loose band makes low sound.
24. Simple Pulley or Lever (Mechanical Advantage)
Materials: String, small bucket, stick or hanger, load like small toys.
Steps: Build a simple lever or pulley and lift a load — compare effort needed with and without pulley.
What you’ll learn: Simple machines make work easier by changing force direction or amount.
Example result: Using a pulley requires less effort to lift the bucket.
25. Water Filtration (Clean Dirty Water)
Materials: Plastic bottle cut in half, gravel, sand, cotton, dirty water.
Steps: Layer cotton, sand, and gravel in inverted bottle and pour dirty water — filtered water collects below.
What you’ll learn: Filtration removes big dirt particles (but may not remove germs).
Example result: Water looks clearer after passing through layers.
26. Grow Bean in a Zip Bag (Observe Roots)
Materials: Beans, paper towel, zip-lock bag, water, tape.
Steps: Moisten paper towel, put beans inside bag pressed against window, tape and watch roots and shoots grow.
What you’ll learn: Seed germination and root/shoot growth are easy to observe.
Example result: Roots grow downward and shoots upward in a few days.
27. Make a Rain Cloud in a Jar (Cloud & Rain)
Materials: Jar, shaving cream, food coloring, water.
Steps: Fill jar with water, put shaving cream on top (cloud), drop colored water on cloud — eventually “rain” falls through.
What you’ll learn: Clouds hold water until they become heavy and rain falls.
Example result: Colored droplets pass through shaving cream into water like rain.
28. Capillary Action in Plants (Colored Flowers)
Materials: White flowers (carnations), cups of water, food coloring.
Steps: Put flowers in colored water and watch petals change color over days.
What you’ll learn: Water moves up plant stems carrying color — capillary action.
Example result: Flower petals become tinted with the dye color.
29. Make a Simple Barometer (Air Pressure)
Materials: Jar, balloon, rubber band, straw, tape, paper for scale.
Steps: Stretch balloon over jar opening and tape straw on top to point at a paper scale — straw moves with air pressure changes.
What you’ll learn: Air pressure pushes on surfaces and changes with weather.
Example result: Straw moves up or down when air pressure changes.
30. Explore Magnets (Attract & Repel)
Materials: Several magnets, paper clips, coins, plastic, iron objects.
Steps: Test which items stick to magnet and how magnets push or pull depending on poles.
What you’ll learn: Magnetic materials react; like poles repel and opposite poles attract.
Example result: Paper clips stick; plastic and coins don’t.
31. Make a Balance Scale (Mass Comparison)
Materials: Coat hanger or stick, string, two cups, small objects to weigh.
Steps: Hang cups on both ends and compare which side drops when you add objects.
What you’ll learn: Balance compares mass — heavier side goes down.
Example result: Three marbles on one side balance two larger stones on the other.
32. Baking Soda Color Change (pH Test with Cabbage)
Materials: Red cabbage juice (boil cabbage), small cups, baking soda (base), vinegar (acid).
Steps: Put cabbage juice in cups, add baking soda or vinegar and watch color change.
What you’ll learn: pH changes (acid/base) make cabbage juice change color.
Example result: Acid turns juice pink; base turns it green/blue.
33. Make Fossils (Clay & Plaster)
Materials: Clay or playdough, small shells or leaves, plaster of Paris (adult help).
Steps: Press object into clay, remove to leave impression, pour plaster to make a fossil replica.
What you’ll learn: Fossils are impressions left in earth materials over time.
Example result: A hard plaster cast that looks like the original shell print.
34. Tooth Decay Model (Egg in Soda)
Materials: Egg (shell like tooth enamel), cola or colored soda, water.
Steps: Put eggs in cola and plain water for a few days and compare shells.
What you’ll learn: Sugary, acidic drinks can damage tooth enamel.
Example result: Egg in cola becomes stained and softer than egg in water.
35. Make a Kaleidoscope (Reflection & Patterns)
Materials: Cardboard tube, small mirrors or reflective paper, beads or sequins, paper.
Steps: Arrange mirrors in triangle inside tube, add beads at one end, look through — rotate for patterns.
What you’ll learn: Multiple reflections create repeating patterns.
Example result: Colorful symmetric patterns that change when you turn the tube.
36. Bending Water with Static
Materials: Plastic comb, running tap, dry hair or wool.
Steps: Rub comb on hair to charge it, bring near a thin stream of water — water bends toward comb.
What you’ll learn: Static electricity attracts polar water molecules.
Example result: Stream curves slightly toward the charged comb.
37. Build a Simple Wind Vane (Measure Wind Direction)
Materials: Straw, pin, stick, paper, pencil.
Steps: Make arrow vanes and mount on pin so it rotates freely; watch which way it points in wind.
What you’ll learn: Wind vane shows direction from which wind blows.
Example result: Arrow points toward wind direction during a breeze.
38. Make a Mini Greenhouse (Plant Growth & Humidity)
Materials: Small plant pot, clear plastic bag, tray.
Steps: Cover small plant with clear bag and observe how moisture collects and plant grows faster.
What you’ll learn: Greenhouse traps moisture and warmth that helps plants grow.
Example result: Plant in bag stays moist and may grow faster than uncovered plant.
39. Color Mixing with Water
Materials: Clear cups, water, food coloring, dropper.
Steps: Put primary colors in cups and mix small amounts in an empty cup to make secondary colors.
What you’ll learn: Primary colors combine to make new colors.
Example result: Blue + yellow = green; red + blue = purple.
40. Make a Simple Siphon (Liquid Transfer)
Materials: Tube, two containers of water (different levels), adult help.
Steps: Fill tube with water, place one end in the higher container and the other in the lower; water flows.
What you’ll learn: Gravity and pressure let liquids move from higher to lower places.
Example result: Water keeps flowing until levels match.
41. Build a Solar Oven (Heat from Sun)
Materials: Pizza box, aluminum foil, plastic wrap, black paper.
Steps: Line box with foil, place black paper inside, cover with plastic wrap and angle toward sun to warm small snacks.
What you’ll learn: Sunlight can be converted to heat for cooking.
Example result: Marshmallow or s’more inside gets warm and slightly melted on a sunny day.
42. Make a Model of the Water Cycle
Materials: Plastic bowl, small cup, plastic wrap, ice, water, marker.
Steps: Put water in bowl and cup in center, cover with plastic wrap and put ice on top — watch condensation and “rain” drip into cup.
What you’ll learn: Evaporation, condensation, and precipitation cycle water.
Example result: Water droplets form under plastic and drip into cup like rain.
43. Observe Transpiration (Plastic Bag on Leaf)
Materials: Small potted plant, clear plastic bag, string.
Steps: Cover one leaf with plastic bag and tie; after a day, water droplets form inside bag.
What you’ll learn: Plants release water vapor through leaves (transpiration).
Example result: Tiny drops inside bag show water loss from leaf.
44. Make a Simple Seismograph (Shake Detector)
Materials: Box, paper roll or string, marker, small weight, ruler.
Steps: Stick a marker to a weighted pendulum and let it draw on paper while you gently shake table to see lines change.
What you’ll learn: Earthquakes make ground move and a seismograph records motion.
Example result: Smooth lines become wavy when shaking happens.
45. Magnetic Scavenger Hunt (Find Magnetic Items)
Materials: Magnet, list, bag.
Steps: Walk around the house or classroom finding magnetic objects and collect them.
What you’ll learn: Which materials are magnetic (iron, steel) and which are not (plastic, wood).
Example result: Paper clips and nails are magnetic; coins may not be.
46. Make a Model Solar System (Scale & Order)
Materials: Styrofoam balls or paper, paint, string.
Steps: Paint planets and hang them in order from the sun to show size differences and distances (not to scale but in order).
What you’ll learn: Planets orbit the sun and have different sizes.
Example result: A classroom mobile showing Mercury to Neptune in order.
47. Growing Roots vs. Shoots (Plant Direction)
Materials: Two seeds or seedlings, two small pots, one tilted pot.
Steps: Plant one pot straight and one tilted; observe how roots grow down and shoots go up.
What you’ll learn: Roots grow with gravity (down); shoots grow toward light.
Example result: Roots curve downward even in tilted pot.
48. Make a Simple Water Wheel (Energy & Motion)
Materials: Bottle caps or spoons, cardboard, skewer, tape, water flow source.
Steps: Attach spoons to wheel, run water onto them and watch wheel turn.
What you’ll learn: Moving water can turn a wheel — basic idea of water-powered energy.
Example result: Wheel spins when water hits spoons showing motion from flowing water.
49. Compare Paper Strength (Material Testing)
Materials: Different papers (newspaper, tissue, cardboard), water, weights.
Steps: Test which paper holds more weight when supported as a bridge or get wet to see strength change.
What you’ll learn: Material properties change when wet or with different thicknesses.
Example result: Cardboard holds more weight than tissue.
50. Simple Leaf Chromatography (Find Plant Pigments)
Materials: Fresh leaves, mortar or spoon, rubbing alcohol, small jar, coffee filter.
Steps: Crush leaf in rubbing alcohol to extract pigment, put extract on paper, let solvent travel — pigments separate.
What you’ll learn: Leaves have several pigments (green, yellow, orange) used in photosynthesis.
Example result: Bands of different colors appear showing pigments in the leaf.
How to present your science project
- Title page: Project name, your name, class, date.
- Question: What are you trying to find out?
- Materials: Short list for others to copy.
- Method: Simple steps in order.
- Results: Table, drawing, or photo and short description of what happened.
- Conclusion: Answer your question. What did you learn?
- Extra: Add what you would change next time or try differently.
Safety rules for science projects for class 3
- Always ask a teacher or adult before starting.
- Wear protective gear if needed (gloves, goggles).
- Don’t taste or smell unknown chemicals.
- Use hot things only with adult help.
- Clean up after experiments and wash hands.
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Final thoughts
These science project ideas for class 3 are chosen to be simple, safe, and fun. They help you learn important science ideas like gravity, plant growth, electricity, forces, materials, and the water cycle.
Try one project at a time, take notes, and explain what you saw. Good projects are about asking questions, testing carefully, and sharing what you discover.
If you want, I can make a printable worksheet or a one-page science fair board layout for any one of these project ideas.
Tell me which project you choose and I’ll prepare a ready-to-print poster layout that you can copy-paste and use for your class presentation.
