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Neural Network Forward Pass

Beginner15-20 minutes

Join us on a journey to predict whether a student named Alex will pass tomorrow's test! Using Alex's study time, sleep, and previous score, we'll watch a neural network make its prediction step-by-step. You'll see how data flows through layers of neurons, how patterns are detected, and how the network arrives at its final decision. This is the same fundamental process used by all neural networks - from image recognition to language models!

What You'll Learn

Real-World AI Applications
Pattern Recognition
Neurons & Weights
Activation Functions
Making Predictions

Prerequisites

Recommended knowledge before starting this visualization

  • Basic understanding of functions
  • No advanced math required!

Interactive Visualization

Step 1 of 8
Progress0%

šŸŽ“ The Problem: Will This Student Pass?

Meet Alex, a student preparing for tomorrow's exam. We have three pieces of information about Alex:

• Hours Studied Today: 7 hours • Hours Slept Last Night: 8 hours
• Previous Test Score: 85%

Can we predict if Alex will pass (≄70%) or fail (<70%) tomorrow's test? Let's use a neural network to find out!

This network has been "trained" on data from thousands of students to recognize patterns between study habits and test outcomes.

Neural Network State

Real-time calculation with actual math

+0.40-0.60+0.30-0.50+0.20-0.70+0.50-0.30+0.60-0.40+0.35-0.45+0.40-0.60+0.30-0.50+0.20-0.70+0.50-0.300.000.000.000.000.000.000.000.000.00InputHidden 1Output
Positive (Excitatory)
Negative (Inhibitory)
Thickness = Strength

Key Takeaways

🧮 Weighted Sums

Each neuron computes a weighted sum of its inputs plus a bias. This linear combination is the foundation of how neurons process information.

⚔ Activation Functions

Non-linear activation functions allow networks to learn complex patterns. Without them, multiple layers would collapse to a single linear transformation.

šŸ”„ Layer-by-Layer Processing

Information flows sequentially through layers. Each layer transforms the data, building increasingly abstract representations from input to output.

šŸŽÆ Predictions

The output layer produces the network's predictions. During training, these predictions are compared to true values, and errors are used to adjust weights.

Next Steps

Continue your learning journey

Now that you understand forward propagation, learn how networks optimize their weights:

Continue to Gradient Descent