10 Easy Science Experiments for Kids at Home or School

By the Ozobot Education Team — STEM curriculum specialists

Quick answer: A science experiment tests a specific, answerable question by changing one variable, keeping everything else consistent, and measuring the result — that's what separates it from an open-ended activity. Below are 10 easy, age-graded experiments for PreK through grade 8, covering buoyancy, plant growth, erosion, insulation, robot motion, and even AI computer vision accuracy, each with an optional Ozobot coding extension.

Easy science experiments for kids turn everyday questions into opportunities to investigate, measure, and discover. Children can explore forces, motion, plants, weather, engineering, robotics, and artificial intelligence using classroom materials—and, in many cases, an Ozobot coding robot.

The most effective science experiments do more than create an exciting result. They encourage students to make a prediction, change one variable, record what happens, and use evidence to explain their findings.

This post is Part 2 of our STEM Activities series. For the full age-by-grade overview of hands-on projects, see our pillar guide, 18 Best STEM Activities for Kids by Grade (PreK–8th Grade).

What Makes an Activity a Science Experiment?

A science experiment begins with a question that can be tested. Students make a prediction, conduct a fair test, collect observations or measurements, and compare the results with their original hypothesis.

A simple experimental process includes:

1. Ask a testable question.
2. Make a prediction.
3. Identify what will be changed.
4. Decide what will be measured or observed.
5. Keep the other conditions consistent.
6. Conduct multiple trials when possible.
7. Record and compare the results.
8. Use evidence to form a conclusion.

As students progress through the grade levels, their investigations can include more detailed measurements, controlled variables, repeated trials, data tables, and graphs. The Next Generation Science Standards emphasize fair tests, controlled variables, and evidence-based explanations as students develop their investigation skills. Next Generation Science Standards

Science Experiments for Kids at a Glance

1. Predict Which Objects Will Sink or Float

Question

Which characteristics determine whether an object sinks or floats?

Materials

• Clear container filled with water
• Several water-safe objects
• Paper and pencil
• Towels for spills

Instructions

Ask students to examine each object and predict whether it will sink or float. Record the predictions before placing the objects into the water one at a time.

After testing, sort the objects into two groups and compare the results. Encourage students to look for patterns involving material, shape, size, and whether the object contains trapped air.

What Students Learn

This experiment introduces prediction, observation, sorting, and buoyancy. Students may initially assume that every heavy object sinks or every small object floats, giving them an opportunity to revise their thinking based on evidence.

Ozobot Extension

Create a sorting map with one path labeled "sink" and another labeled "float." Students can use Color Codes to program Evo toward their prediction before testing the object.

2. Make Water "Walk" Between Cups

Question

Can water travel between two containers without being poured?

Materials

• Three clear cups
• Water
• Paper towels
• Food coloring

Instructions

Fill the first and third cups halfway with water, leaving the middle cup empty. Add one color to the first cup and a different color to the third.

Fold two paper towels into narrow strips. Place one end of the first strip in the first cup and the other end in the empty cup. Repeat between the third and middle cups.

Ask students to predict what will happen. Observe the cups at regular intervals and record how the water level and colors change.

What Students Learn

Water moves through the small spaces in the paper towel through capillary action. As the colored water reaches the middle cup, the two colors begin to mix.

Ozobot Extension

Have students program Evo's lights to represent the original colors and the new color created when they mix. Students could also draw a rainbow path and use Color Codes to represent the movement of the water.

3. Investigate How Light Affects Plant Growth

Question

How does the amount of light a plant receives affect its growth?

Materials

• Identical seeds
• Identical containers
• The same type and amount of soil
• Water
• Ruler
• Data sheet

Instructions

Plant the same type and number of seeds in identical containers. Place the containers in locations that receive different amounts of light while keeping the soil, water, temperature, and measurement schedule as consistent as possible.

Measure the plants regularly and record:

• Germination date
• Plant height
• Number of leaves
• Color and general appearance

Students can graph the measurements and compare the plants at the end of the investigation.

What Students Learn

This experiment introduces living systems, plant needs, data collection, and controlled variables. It also shows why longer experiments require consistent observation and careful documentation.

Ozobot Extension

Create a measurement route with stations for each plant. Students can program Ozobot to travel between the stations in a consistent order as they collect and record their data.

4. Track How a Shadow Changes

Question

How does a shadow's position and length change throughout the day?

Materials

• Chalk
• Ruler or measuring tape
• An upright outdoor object
• Data sheet
• Clock

Instructions

Choose an object that will remain in the same position throughout the day. At several scheduled times, trace or mark the end of its shadow and measure the shadow's length.

Students should record:

• The observation time
• The shadow's direction
• The shadow's length
• Weather conditions

Compare the measurements and discuss why the shadow changed even though the object did not move.

What Students Learn

The apparent movement of the Sun across the sky changes the angle at which sunlight reaches an object. This affects the position and length of the shadow.

NASA offers additional Earth and space science activities for a variety of grade levels, including activities involving the water cycle, soils, sunlight, and shadows. NASA Science at Home

5. Experiment With Balance Using a Seesaw

Question

How does an object's distance from the center of a seesaw affect its balance?

Materials

• A simple seesaw or lever
• Small classroom objects or weights
• Ruler
• Data sheet

Instructions

Place objects with equal weights at the same distance from the seesaw's center and observe the result. Move one object closer to or farther from the center while keeping the weights the same.

Students can then test:

• Equal weights at different distances
• Different weights at equal distances
• Different weights at different distances

Record which combinations balance and which cause one side to move downward.

What Students Learn

A seesaw is a lever with a pivot point called a fulcrum. Both an object's weight and its distance from the fulcrum affect the seesaw's motion and balance.

Ozobot Extension

The Ozo Goes on a Seesaw STEAM Kit allows students to explore force, motion, balance, and simple machines while incorporating Ozobot into the investigation.

6. Build and Test a Paper Bridge

Question

Which paper shape can support the most weight?

Materials

• Identical sheets of paper
• Two stacks of books or blocks
• Coins or small weights
• Tape, if permitted
• Data sheet

Instructions

Place two stacks of books a short and equal distance apart. Lay one flat sheet of paper across the gap and add coins one at a time until the bridge bends or collapses.

Repeat the test using different paper designs, such as:

• Folded edges
• An accordion fold
• A curved arch
• A rolled paper tube

Use the same paper size, bridge span, and type of weight for every trial. Record how much weight each design supports.

What Students Learn

Changing the shape of a material can change how forces are distributed through a structure. Students also experience the engineering design process as they test, compare, and improve their bridges. In an upcoming blog about hands-on engineering projects, you'll learn more about age-graded design challenges built around exactly this kind of test-and-improve cycle.

NGSS engineering guidance encourages students to conduct fair tests, control variables, and identify areas where a model or prototype could be improved. NGSS Engineering Design

Ozobot Extension

Students can design a bridge wide and stable enough for Evo to cross after completing the weight test. Test the robot bridge close to the floor or tabletop to prevent the robot from falling.

7. Model How Water Causes Erosion

Question

How does the slope of the land affect the movement of soil?

Materials

• Two shallow trays
• Soil or sand
• Water
• Cup with a small pouring opening
• Books or blocks
• Ruler
• Towels

Instructions

Fill both trays with the same amount of soil and shape the surfaces as consistently as possible. Keep one tray relatively flat and elevate one end of the other tray to create a steeper slope.

Slowly pour the same amount of water from the same height onto each tray. Observe how far the soil travels and where it is deposited.

Students can compare:

• The channels created by the water
• The amount of soil displaced
• The distance the soil traveled
• The sediment collected at the bottom

What Students Learn

Flowing water can move and deposit Earth materials. Changing the slope provides a testable variable that helps students investigate how land shape influences erosion.

Ozobot Extension

After the investigation, students can draw a model of the water's path and program Evo to follow the route from the highest point to the area where sediment collected.

8. Compare Insulating Materials

Question

Which material slows temperature change most effectively?

Materials

• Identical containers
• Room-temperature or chilled water
• Thermometer
• Different insulating materials
• Rubber bands or tape
• Timer

Instructions

Wrap identical containers with different materials, such as fabric, paper, felt, aluminum foil, or bubble wrap. Leave one container unwrapped as the control.

Add the same amount of water at the same starting temperature to every container. Measure and record the temperature at consistent intervals.

Students should compare how much the temperature changed in each container and determine which material provided the most effective insulation.

What Students Learn

Insulators slow the transfer of thermal energy. This experiment also introduces control groups, quantitative measurements, and the importance of maintaining consistent conditions.

Ozobot Extension

Program Ari or Evo to act as a timer, move to each testing station, or signal when it is time to record the next temperature.

9. Measure How Programmed Speed Affects Travel Time

Question

How does Evo's programmed speed affect the time required to travel a fixed distance?

Materials

• Evo
• Coding device
• Ozobot Blockly
• Measuring tape
• Timer
• Masking tape
• Data sheet

Instructions

Mark a starting line and finish line a fixed distance apart on a smooth, level surface. Program Evo to travel the same route at several different speeds.

Run multiple trials at each speed and record the travel time. Keep the distance, surface, starting position, and movement instructions consistent.

Students can calculate the average time for each speed and create a graph showing the relationship between programmed speed and travel time. In an upcoming blog about fun math activities, you'll learn more about hands-on ways to build the averaging, graphing, and data-reading skills this kind of experiment relies on.

What Students Learn

This robotics experiment connects programming with motion, distance, time, repeated trials, averages, and data visualization. It also helps students distinguish between the variable they change and the result they measure.

Investigation Questions

• Did Evo take the same amount of time during every trial?
• Why are repeated trials useful?
• Which factors could have affected the measurements?
• How could the procedure be made more consistent?

10. Test the Accuracy of Computer Vision

Note: Some school districts currently restrict student-facing generative AI tools for these grade levels — check your school or district's current AI policy before planning this activity.

Question

How do lighting, camera position, or image design affect an AI system's ability to identify a target?

Materials

• Ari or Evo
• Ozobot Editor
• Coding device
• USB document camera
• Two clearly different target images
• Data table

Instructions

Create a program that asks an LLM to examine an image from the camera and direct Ozobot toward one of two targets.

Begin with both targets clearly visible under consistent lighting. Run several trials and record whether the system selects the correct target.

Next, change one condition, such as:

• The brightness of the room
• The camera angle
• The distance between the camera and targets
• The size of the images
• The similarity between the two targets
• The wording of the prompt

Calculate the percentage of correct responses under each condition.

What Students Learn

Computer vision systems use images as data, but their performance can be affected by the quality of the image and the instructions they receive. Students learn that AI-generated results should be tested and evaluated rather than automatically assumed to be correct.

Investigation Questions

• Under which conditions was the system most accurate?
• Which variable had the greatest effect?
• Did changing the prompt improve the results?
• Why should AI outputs be checked by a person?
• How might lighting and camera position affect a real autonomous robot?

How Do You Choose a Science Experiment for a Child?

Choose an experiment that matches the student's age, background knowledge, available materials, and ability to work independently.

A good experiment should include:

• A question the student can understand
• A variable that can be changed safely
• A result that can be observed or measured
• Materials appropriate for the setting
• Enough time for testing and discussion
• Opportunities to record and explain the results

Younger children may focus on predictions and visible changes. Upper-elementary students can begin controlling variables and collecting measurements. Middle school students can analyze multiple trials, calculate averages, graph data, and evaluate sources of error. If you're choosing a coding robot or classroom kit to support experiments like these, an upcoming blog about choosing the best STEM kit will break down what to look for at each age and grade band.

How Can Teachers Make Science Experiments More Meaningful?

The learning should not end when the experiment produces a result. Ask students to explain what happened, support their ideas with evidence, and identify what they would change during another trial.

Teachers can deepen an investigation by asking:

• What did you predict, and why?
• What evidence supports your conclusion?
• Which variable did you change?
• What did you keep the same?
• Were the results consistent?
• What may have affected the outcome?
• What new question do you have?
• How could you improve the experiment?

NOAA also provides short, hands-on Earth science activities that can be completed in approximately 15 to 30 minutes, giving teachers additional ways to incorporate scientific investigation into the classroom. NOAA Hands-On Science Activities

Frequently Asked Questions About Science Experiments for Kids

What are some easy science experiments for kids? Easy science experiments include testing which objects sink or float, observing water travel through paper towels, growing plants under different light conditions, tracking shadows, building paper bridges, and comparing insulating materials.

What is the easiest science experiment to do at home? A sink-or-float experiment is one of the easiest options because it requires only water, a container, and several household objects. Children can make predictions, test each item, sort the results, and explain the patterns they observe.

What is the difference between a science activity and an experiment? A science activity may demonstrate or explore a concept. A science experiment tests a specific question by changing a variable and observing or measuring the result.

How can coding be incorporated into a science experiment? Coding can control a robot's speed, movement, lights, sounds, sensors, or responses. Students can change one part of the program, measure the effect on the robot's behavior, and compare the results across multiple trials.

Can robotics help teach the scientific method? Yes. Robotics gives students visible and measurable results that can be tested repeatedly. Students can form a hypothesis, change a programmed variable, collect data, debug unexpected behavior, and use evidence to reach a conclusion.

What science skills do children develop through experiments? Science experiments help children practice observation, prediction, measurement, data collection, comparison, critical thinking, communication, and evidence-based reasoning.

Turn Curiosity Into an Investigation

Science begins with curiosity, but an experiment takes the next step by turning a question into a test.

Whether students are observing a plant, building a bridge, measuring a robot's movement, or testing an AI system, the same process applies: ask a question, make a prediction, collect evidence, and use the results to decide what they learned.

Explore Ozobot coding robots, STEAM Kits, and classroom lessons to give students more ways to investigate science through hands-on coding, engineering, and robotics.

This is Part 2 of our STEM Activities series. New guides post weekly — check back soon, or explore what's live so far below.

Final Thoughts

• 18 Best STEM Activities for Kids by Age (PreK–8) — An age-graded overview of activities across every stage from preschool through middle school.

(more guides coming soon)

• Engineering Activities for Kids: 10 Hands-On STEM Projects — Design challenges that ask kids to build, test, and improve a solution.
• How to Choose the Best STEM Kit for Kids by Age — A buying guide for matching a STEM kit to a child's age and learning goals.
• 10 Fun Math Activities for Kids by Grade — Hands-on ways to build number sense from counting through algebra.