What is CSEEL and what does it offer?

CSEEL (Center for Scientific Exploration and Experiential Learning) is a premier Indian STEM educational initiative offering hands-on science experiments, 3D live laboratory simulations, curriculum-aligned project kits, teacher training workshops, and national science conclaves aligned with NEP 2020.

How does CSEEL support NEP 2020 experiential learning?

CSEEL shifts education from rote memorization to active inquiry and hands-on experimentation. Students observe, build, analyze, and apply scientific concepts to real-world challenges, developing critical thinking and scientific temper as envisioned by NEP 2020.

What subjects and classes are covered in CSEEL simulations and experiments?

CSEEL provides comprehensive physics, chemistry, biology, environmental science, and applied robotics experiments and virtual simulations for students from Class 6 through Class 12, mapped to CBSE, ICSE, and state curricula.

How can schools, educators, and students access CSEEL programs?

Institutions, teachers, and students can explore live simulations, order DIY lab kits, register for national seminars, and join the CSEEL EduNetwork by visiting https://www.cseel.org.

Galton Board & Experimental Verification of Normal Distribution

Experiment video

What you will learn

Demonstrate the Central Limit Theorem and normal (Gaussian) distribution curve by dropping 1,000 steel ball bearings through a triangular quincunx pegboard (Galton Board).

Materials needed

Acrylic Galton Board apparatus with 12 rows of staggered hexagonal pegs and collection bins
Acrylic Galton Board apparatus with 12 rows of staggered hexagonal pegs and collection bins
₹50
What is it?
Desktop demonstration Galton Board (Quincunx) with brass pins and transparent acrylic casing.
Specifications
Pin Array
10 rows of staggered brass pegs (55 pins total)
Collection Bins
11 vertical parallel collection channels
Ball Bearings
1,000 precision 3.0 mm chrome steel ball bearings
Casing
300 mm × 200 mm scratch-resistant optical acrylic
Steel ball bearings (2 mm diameter) ,000
Steel ball bearings (2 mm diameter) ,000
₹95
What is it?
Built-in spirit level and leveling adjustment feet.
Specifications
Spirit Level
Circular bullseye spirit level mounted on frame
Leveling
Twin threaded brass leveling thumb screws
Millimeter scale for measuring bin fill heights
Millimeter scale for measuring bin fill heights
₹140
What is it?
Statistical data sheet with pre-calculated Pascal triangle and binomial probability coefficients.
Specifications
Format
Laminated reference card with normal distribution z-table
Smartphone camera with high-speed video capture
Smartphone camera with high-speed video capture
₹185
What is it?
Standard laboratory apparatus used in Galton Board & Experimental Verification of Normal Distribution.
Specifications
Category
Mathematics Apparatus
Grade
CBSE / NEP 2020 Laboratory Standard
Graph paper for plotting frequency histogram and bell curve
Graph paper for plotting frequency histogram and bell curve
₹230
What is it?
Standard laboratory apparatus used in Galton Board & Experimental Verification of Normal Distribution.
Specifications
Category
Mathematics Apparatus
Grade
CBSE / NEP 2020 Laboratory Standard

Tick items as you collect them. Tap + to see the product, specifications and buy options.

Stay safe

The board must be set strictly perpendicular using a spirit level; tilt causes asymmetric skewness.
Release balls smoothly without shaking the apparatus.
Ensure pegs and balls are clean and dry to minimize electrostatic or frictional bias.
Verify that all bins have uniform internal cross-sectional width.

Steps

0 of 7 steps done

1Set the Galton Board strictly vertical on a level laboratory table.
Observation
Inspect Galton Board apparatus: triangular array of 10 horizontal rows of staggered brass pins leading to 11 collection bins.
Safety
Ensure board is mounted vertically on level surface; verify with built-in bubble spirit level.
2Inspect that all 1,000 ball bearings are collected in the upper funnel reservoir.
Observation
Load 1,000 precision steel ball bearings (diameter 3 mm) into top funnel hopper reservoir.
Safety
Keep clear acrylic cover securely screwed down so steel balls do not bounce onto room floor.
3Release the gate mechanism to allow the balls to drop through the triangular peg array.
Observation
Release gate lever smoothly; watch ball bearings cascade down pin triangle, deflecting randomly 50% left or 50% right at each pin.
Safety
Release at steady flow rate to prevent ball jamming at funnel neck.
4At each peg collision, a ball has an equal probability p = 0.5 of bouncing left and 1 - p = 0.5 of bouncing right.
Observation
Observe balls collecting in vertical bins at bottom, immediately forming a classic bell-shaped Gaussian distribution curve.
Safety
Do not shake or tilt apparatus while balls are falling.
5Observe the final accumulation of balls in the graduated bins at the bottom.
Observation
Read heights of ball columns in each bin against engraved millimeter scale; record counts across all 11 bins.
Safety
Center bin 6 contains the tallest column (~248 balls), tapering symmetrically toward the outer edges.
6Measure the height of balls (frequency) in each of the 13 bins from left to right.
Observation
Plot frequency histogram and overlay theoretical Binomial(10, 0.5) normal curve: correlation coefficient r > 0.995.
Safety
Invert board gently to return ball bearings into upper reservoir for repeat trials.
7Plot the bin number (x-axis) versus ball height (y-axis): draw the smooth envelope curve to demonstrate the classic Gaussian bell-shaped distribution.

Tap + on a step to see what you will observe and any safety tips.

Record your observations

Bin Number (Left to Right)	Theoretical Binomial Probability P(X=k)	Expected Balls (N = 1000)	Actual Counted Balls	Relative Frequency (%)
Bin 1 (Far Left, k=0)	0.0010	1 ball	1 ball	0.1%
Bin 2 (k=1)	0.0098	10 balls	8 balls	0.8%
Bin 3 (k=2)	0.0439	44 balls	42 balls	4.2%
Bin 4 (k=3)	0.1172	117 balls	121 balls	12.1%
Bin 5 (k=4)	0.2051	205 balls	210 balls	21.0%
Bin 6 (Center Mean, k=5)	0.2461 (Peak)	246 balls	248 balls	24.8% (Peak modal class)
Bin 7 (k=6)	0.2051	205 balls	198 balls	19.8%
Bin 8 (k=7)	0.1172	117 balls	115 balls	11.5%
Bin 9 (k=8)	0.0439	44 balls	43 balls	4.3%
Bin 10 (k=9)	0.0098	10 balls	11 balls	1.1%
Bin 11 (Far Right, k=10)	0.0010	1 ball	2 balls	0.2%

Tap a highlighted cell to write your own observation.

Result and conclusion

Steel balls accumulating in bottom bins form a smooth symmetric bell-shaped Gaussian curve, empirically proving the convergence of binomial distribution B(n, 0.5) to normal distribution N(μ, σ²).

P(X = k) = (n choose k) · p^k · (1-p)^(n-k); lim (n -> ∞) Binomial(n, 0.5) = Normal Distribution N(μ = np, σ² = np(1-p))

Observation	What it means
Central Limit Theorem Physical Realization	Repeated 50/50 independent binary deflections across 10 peg rows yield a stunning physical bell-shaped normal curve.
Symmetric Binomial Peak at Center	Peak modal frequency occurs at Bin 6 (μ = n·p = 10 × 0.5 = 5), containing 24.8% of all dropped ball bearings.
Gaussian Bell Curve Emergence	Experimental ball counts match theoretical Pascal triangle binomial expansion coefficients (1, 10, 45, 120, 210, 252, 210, 120, 45, 10, 1) within 1.5% margin.
Randomness Yields Strict Determinism	While the path of any individual ball bearing is completely unpredictable and random, the collective distribution of 1000 balls is rigorously deterministic.

Ball Count Frequency Distribution vs Bin Position (Gaussian Bell Curve)

Sample readings. Replace with your own results.

Experiment photos

Before the experimentDuring the experimentResult