Grades 3–5

What's Inside a Prediction?

Today we open up an AI and see what's inside.

Computers make predictions

A prediction is a guess about something we don't know yet, made from something we do know.

🌧️

Weather

The weather app says it will rain.

📺

Videos

A video site picks your next video.

💬

Words

A phone guesses your next word.

Where has a computer made a prediction for you?

Elementary School · Grades 3–5

Let's make a prediction

A zoo gets more visitors when it's sunny.

1 hour of sun → 200 visitors
3 hours of sun → ?600 visitors

How did you know? You multiplied 3 × 200.

That is exactly what a neural network does!

Elementary School · Grades 3–5

Inside a neural network

200 3 hours of sun ?600 visitors

Input value

The number that goes in: 3 hours of sun.

Weight

The number on the connection. The input is multiplied by it.

Output value

The number that comes out: the prediction.

Elementary School · Grades 3–5

Words to know

AI
Computer programs that do things that usually take human thinking.
Prediction
A guess about something we don't know yet.
Neural network
A kind of AI that passes numbers along connections and multiplies them.
Input value
The number that goes into the network.
Weight
The number on a connection. The input is multiplied by it.
Output value
The number that comes out: the network's prediction.
Target output
The real answer. The output should match it.

Elementary School · Grades 3–5

Activity 1

Predict the cricket chirps

The Cricket Chirp Predictor Forward Propagation tab ↗

Crickets chirp faster when it's warm: 6 more chirps for every degree. So the weight is 6.

  1. Work out the output on paper.
  2. Type in your prediction.
  3. Step on to check.
6 15 degrees ?90 chirps

Say your multiplication out loud to your partner!

Elementary School · Grades 3–5

Activity 2

Fix the phone battery

The Phone Battery Predictor Forward Propagation tab ↗

The weight is wrong! A 1-hour video really uses 12% of the battery.

  1. Click the weight. Change it.
  2. Step through all four videos.
  3. Green lines mean it matches!
5 1 hours 5 battery % 12 target

Too big or too small? Should the weight go up or down?

Elementary School · Grades 3–5

Let's talk

  1. What does the weight do?
  2. What happened to the outputs when you made the weight bigger?
  3. How did you find the right weight for the phone battery?
  4. Real AI has millions of weights. Who do you think sets them all?

Elementary School · Grades 3–5

Exit ticket

  1. A network has a weight of 3. The input is 5. What is the output?
  2. In one sentence, what does a weight do?

Elementary School · Grades 3–5

Real AI is made of the same pieces

The weather app and the next-word guesser use inputs, weights and outputs, just like today. They just have many more of them.

And the computer sets the weights itself, by checking its answers and fixing its mistakes, over and over.

Keep exploring at iinnoo.app

Elementary School · Grades 3–5