Best Physical Science Projects for 3rd, 4th, and 5th Grades

Looking for the best physical science projects for 3rd, 4th, or 5th grade students? Try these simple activities! The age-appropriate resources also address Next Generation Science Standards (NGSS).

Whether you’re using them for classroom learning or science fair projects, they’ll be a hit!

Estimated reading time: 13 minutes

What Do the Best Science Projects Have That Others Don’t?

The best physical science projects for 3rd, 4th, and 5th grade students incorporate science practices. In other words, they let kids act as true scientists. Specifically, they ask testable questions, develop models and/or plan investigations, analyze and interpret data, construct explanations, and communicate.

Activities can be broken into three general categories: physics (forces and motion, energy), applications to technology (waves in water, the eye and light, and patterns), and chemistry (matter). Integrated experiences help kids make connections between these categories – and with other branches of science.

No images appear on this page. To read more and/or see photos of each set of activities, click the links that appear in the text. If you’d like to purchase supporting resources (directions, reading materials and reference guides, lab sheets, etc.), use the buttons.


In 3rd grade physical science, kids explore balanced and unbalanced forces, patterns in motion, static electricity and magnetism. To extend that, 4th graders explore speed, forms, and transfer of energy, as well as collisions. 5th graders, like Galileo Galilei, consider gravity.

Physical Science Projects for 3rd Grade

When choosing physical science projects for 3rd grade students, keep it simple.

Balanced and Unbalanced Forces

To explore balanced and unbalanced forces, kids compare situations with the same and different amount or direction of force.

  • Testable Question: How do forces affect the direction of a stationary object?
  • Testable Question: How do forces affect the direction of an object in motion?
  • Kids can explore and explain what happens when the forces they apply are opposite and equal, opposite but unequal, different directions and equal, different directions and unequal.

Static Electricity

Kids investigate a variety of static electricity situations.

  • Testable Question: How does rubbing a balloon on my hair affect it?
  • Students blow up two balloons and rub one on their hair. Then they compare effects when both balloons are held near: someone else’ hair, the wall, each other, an empty aluminum can on its side, a ping-pong ball laying on a table, salt, pepper, a stream of water from the faucet, and/or bubbles.
  • Testable Question: How do gloves made of different materials affect static electricity.
  • Rub each glove on a balloon. Hold it above 20 paper bits. Count how many each attracts/picks up.

Physical Science Projects for 4th Grade

Physical science projects for 4th grade explore forms and transfer of energy (sound, light, heat, current electricity), the relationship between speed and energy, and collisions.

Forms of Energy

For the best physical science project, focus on only one concept.


Sound activities include:

Some concepts, however, are better suited for a science fair project:

  • Testable Question: Is amplitude greater when more force is applied?
  • This simple experiment is super simple. Kids use a spoon to strike various objects with less and greater force.
  • Testable Question: How does length/size affect pitch?
  • You can use a variety of materials for this: flutes of different lengths, glass bottles of different sizes, etc. Look online for more specific ideas.
  • Testable Question: Which materials insulate sound better?
  • Kids yell into a large metal can. Then, one by one, they add different materials and yell again. They should find that soft materials like cloth insulate better than rigid materials like aluminum foil.
  • Testable Question: Does a plastic, wooden, or metal spoon conduct sound better?
  • Tie the middles of a two-meter strings to each of these spoons. For each spoon, wrap the ends of the strings around your two pointer fingers. Then put your pointer fingers in your ears. Lean forward and allow the spoon to strike a table or counter.
  • Testable Question: Does sound travel better through solids, liquids, or gases?
  • For this ambitious project, you’ll need a swimming pool, pennies, and helpers. As the helpers move farther and farther away (at measured distances), they tell if they can hear two pennies clicked together in the air (when they are above water), under water (when they are underwater), and on the side of the pool (when their ears are also resting on the side of the pool).

Light activities in this unit include:

Again, some concepts work better as science fair projects:

  • Testable Question: Which materials are transparent, translucent, opaque?
  • Shine a flashlight on a wall from a short distance. Position different materials between the flashlight and wall. Record if all/most, some, or no light shines on the wall.
  • Testable Question: Which materials reflect light better?
  • Shine a flashlight on a wall from a short distance, this time at an angle (~45 degrees). Position different materials so the light bounces from the object to the wall. Record if all/most, some, or no light shines on the wall.

Thermal energy activities include:

Although working with heat has some safety issues, you can try a few that don’t require super hot materials.

  • Testable Question: How does heat affect movement in water?
  • Fill three cups with hot, room temperature, and cold water. Drop the same amount of food coloring into each cup at the same time. Quickly photograph the results.
  • Testable Question: Which is denser, hot or cold water?
  • Option 1: Add food coloring to cold water. Use a straw or eyedropper to slowly add hot water on top of it. Then try it the other way around by adding cold water to hot water.
  • Testable Question: Does metal, plastic, or Styrofoam insulate (or conduct) heat better?
  • Place equal amounts of hot water in metal, plastic, and Styrofoam cups of the same size. Record the temperature of water in each cup at periodic intervals.
Current Electricity

Electricity activities include:

For a fun physical science fair projects, try this.

  • Testable Question: Which materials conduct (or insulate) electricity?
  • Build a simple circuit with an open path. Connect the open path with a variety of objects. If the bulb lights, the material conducts electricity.

If you’d like to get more specific, limit materials to metals (some conduct, and some don’t.)

Speed and Energy

A variety of activities let kids consider cause-effect relationships between speed and energy. (If you are working on a science fair project, choose something that includes or a finish line and use multiple trials.)

  • Testable Question: How does speed affect thermal energy?
  • Option 1: Rub hands together slowly then faster.
  • Option 2: Rub a pencil up and down slowly then faster.
  • Option 3: Rub a metal hanger slowly then faster.
  • Testable Question: How does mechanical energy affect speed?
  • Option 1: Kids create two balloon launchers. They launch small objects using less and more tension.
  • Option 2: Kids create spool racers. They race one that’s been wound more times with one that’s been would less times to the finish line.
  • Testable Question: How does position (potential energy) affect speed?
  • Using Hot Wheels racetrack (available at many dollar stores), position one of two tracks at a greater angle. Release two toy cars at the same time and record which makes it to the finish line first.
  • Testable Question: How does motion affect speed?
  • Using paper footballs, flick with faster and slower motion (more and less force). Observe which goes faster and record.


This set of collision activities works better in the classroom. Kids build mini pool tables to explore what happens when marbles strike one another.

Physical Science Projects for 5th Grade

Physical science projects for 5th grade students focus more on chemistry. One standard, however, explores a physics concept: gravitational forces.


A variety of situations help kids understand gravity. You can use some of them for science fairs.

  • Testable Question: How does gravity affect falling objects of different weights/masses? (This famous experiment was conducted in the late 1500s by Galileo Galilei from the Leaning Tower of Pisa.)
  • Hold two balls that are the same size but different masses in your hands. Drop both at the same time and observe when they strike the ground. Stand on a chair or ladder to test it from different heights.
  • Testable Question: How does gravity affect objects moving through the air?
  • Throw different objects (cotton balls, paper plates, straws) horizontally. Record/draw their paths.
  • Testable Question: How does gravity affect rolling objects?
  • Roll different objects (marbles, pencils) across a flat surface. Record what happens.

Applications to Technology

In 4th grade physical science, students explore waves and applications to technology. They start off with waves in water. Then they investigate light waves and vision. Finally, with a nod to computer programming, kids consider patterns used to transmit information.

Exploration in 4th Grade

Waves in Water

In this set of activities, kids explore transverse waves. In a STEM challenge, they find the best possible model to simulate waves in water. If your science fair allows models, you could use this for a project.

The Eye, Light, and Vision

Through a specific investigation, students learn how light enables vision.

  • Testable Question: How does light affect vision?
  • With the lights on, place a small object on a table. Photograph it. Leaving the lights on, place a toilet paper tube upright over the object. Photograph it through the hole. Turn the lights off and again photograph it through the hole.

This project can be replicated with different situations. You can also incorporate models and/or diagrams of the eye into your presentation.


In this set of activities, kids explore how humans use patterns to communicate. They try Morse and binary codes, as well as considering patterns from everyday life (stop lights, the teacher clapping, thumbs up/down), etc. It provides a foundation for programming.


5th grade physical science students embark on the study of chemistry.

Physical Science Projects for 5th Grade

Kids love chemistry! Maybe you will find the best physical science project here.

Introduction to Matter

Through a variety of classroom activities, kids use hands-on exploration to deduce that matter is made of particles too small to be seen.

Physical and Chemical Changes

Students explore physical and chemical changes with more hands-on activities. Instead of testing, this project demonstrates different types of evidence of chemical change.

  • Question: What provides evidence of chemical change?
  • Add vinegar to baking soda. (bubbles)
  • Prepare three cups of colored water. Add vinegar, hydrogen peroxide, and bleach. (color)
  • Measure the temperature of a cup of hydrogen peroxide. Stir in some yeast. Measure the temperature again. (heat)
  • Add hydrogen peroxide to a cup of iron filings. (odor)
  • Activate a glow stick. (light)

Properties of Matter

In this module, kids test mystery powders to explore properties of matter. You might also test chemical properties in a science fair project.

  • Testable Question: How do different liquids affect steel wool?
  • Pour different liquids (including water) into the lids of small glass jars. Add steel wool and screw the jar onto the lid. (The jar will be inverted.) Observe over time and photograph.

The Law of Conservation of Mass

These simple conservation of mass activities require more measurement.

  • Testable Question: Which has greater mass, whole or crushed crackers?
  • Place crackers in a zip-type baggie. Seal and mass. Crush the crackers while still in the baggie. Mass again.
  • Testable Question: Which has greater mass, sugar and water separately or sugar dissolved in water?
  • Find the mass of 10 cc (ml) of sugar and 50 ml of water. Stir together so sugar dissolves. Find the mass of the solution. (It’s also interesting to find the volume to illustrate that it is not conserved.)
  • Testable Question: Which has greater mass, water or ice?
  • Measure 30 ml of water into a graduated cylinder. Mass. Cover the graduated cylinder with plastic to prevent evaporation. Place in freezer. The next day, mass again.
  • Testable Question: Is mass conserved during chemical changes?
  • Measure 20 cc of baking soda into a zip-type baggie. Measure 20 ml of vinegar into a small cup. Place the small cup into the baggie and seal. Taking care not to spill the vinegar, mass the baggie and its contents. Spill the vinegar into the baking soda and mass again.

Designing the Best Physical Science Project for a Science Fair

Today, science practices include models. However, many science fairs still subscribe to the traditional scientific method. Before you begin, find out if your event allows models.

The following process moves you through the scientific method and includes a fair test. For physical science projects in 3rd grade, 4th grade, or 5th grade, this experimental design:

  • compares
  • controls variables
  • uses scientific tools for observation and measurement
  • replicates

What if your students aren’t ready for independent physical science projects? No worries! Conduct one experiment and sign up for the science fair as a class. You can use each group’s results as a separate set of data.

Ask a Testable Question

First, you will ask a testable question. It will allow you to compare, predict, observe, and measure.

If, for example, your project focuses on evaporation, which of these questions is actually testable?

  • How does water evaporate?
  • Why does water evaporate?
  • Does salt or fresh water evaporate faster?

Only the last question allows you to compare (salt versus fresh), predict, observe, and measure (with a graduated cylinder).


After you develop a testable question, you should also hypothesize, or predict the result. For example:

  • I hypothesize (or predict) that fresh water will evaporate faster than salt water.

When of the results of your experiment, you will find out if your hypothesis is correct. If not, no worries! You have learned something. Don’t change your hypothesis to match your results. Scientists (and science fair judges) welcome different predictions and outcomes.

Plan and Carry Out an Investigation

Second, you’ll plan and carry out an investigation. The experimental design should match the question. Additionally, it should allow you to compare, control variables, measure, and replicate. For example:

  • Compare – Set up one cup with salt water and one with fresh water. Leave open to the air for one week.
  • Control variables – Other than the salt and fresh water, everything in the experiment must be kept the same: amount and temperature of water, type and size of cups, temperature and humidity in the room, exposure to light and wind, etc.
  • Measure – For this fair test, kids will measure volume with a graduated cylinder. For other labs, they might use a ruler, meter stick, or measuring tape for length; a balance scale for mass; a clock or stopwatch for time; etc.
  • Replicate – Don’t just do the experiment once. Instead, repeat it. For this example, you could set up three sets of cups (three salt water and three fresh water).

Analyze and Interpret Data

As the experiment progresses, observe and record what you see. Additionally, you will measure. When finished, organize, analyze, and interpret your findings.

For a science fair project, create tables and/or graphs of your numeric information. Add photos, drawings, diagrams, etc. to show others what you did and observed.

All of this presents your results.

Draw a Conclusion

From the data, construct explanations. In other words, answer your original question based on your findings. For example:

  • Salt water evaporates faster than fresh water.

Back up your claim with evidence from your experiment.

Now you’re ready to design best physical science project ever. For a top-notch presentation, also include background information that you’ve obtained through research.

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