Data and Probability · Term 4

Chance and Likelihood

Using the language of chance to describe the probability of different outcomes.

About This Topic

Chance and likelihood (AC9M2P01) introduce students to the language of probability. In Year 2, the focus is on identifying outcomes of familiar events and using terms like 'will happen', 'won't happen', 'might happen', 'certain', 'likely', 'unlikely', and 'impossible'. This helps students understand that while some things in life are predictable, others involve an element of randomness.

In an Australian classroom, this can be linked to weather (Is it likely to rain today?), games (What are the chances of rolling a six?), or daily routines. This topic comes alive through games and experiments. When students can physically roll dice, spin spinners, or pull marbles from a bag, they move from 'guessing' to 'predicting' based on the available outcomes. Structured discussion helps them refine their language and justify their choices.

Learning Objectives

• Identify possible outcomes for familiar events.
• Classify events as certain, likely, unlikely, or impossible.
• Explain how changing the conditions of a game can alter the likelihood of winning.
• Compare the likelihood of two different events occurring.

Before You Start

Identifying and Classifying Objects

Why: Students need to be able to sort and group items based on attributes to understand classifying events.

Basic Counting and Number Recognition

Why: Understanding quantities helps students grasp the concept of more or less chance.

Key Vocabulary

Certain	An event that is guaranteed to happen. For example, the sun is certain to rise tomorrow.
Impossible	An event that cannot happen. For example, it is impossible for a cat to lay an egg.
Likely	An event that has a good chance of happening, but is not guaranteed. For example, it is likely to be sunny in Australia in summer.
Unlikely	An event that has a small chance of happening. For example, it is unlikely to snow in Queensland.
Might happen	An event that could happen, but we cannot be sure. For example, you might see a kangaroo on a bushwalk.

Active Learning Ideas

Simulation Game: The Impossible Bag

The teacher has a bag of only blue marbles. Students must use chance language to describe the likelihood of pulling out a red marble ('impossible') or a blue one ('certain'). They then work in pairs to create their own 'likely' and 'unlikely' bags for a partner to guess.

⏱ 30 min·Pairs

Generate mission

Inquiry Circle: The Fair Game?

Groups are given a spinner that is 3/4 red and 1/4 blue. They must predict which colour will 'win' after 20 spins. After conducting the experiment, they discuss why the result happened and how they could change the spinner to make it 'fair' (even chance).

⏱ 40 min·Small Groups

Generate mission

Think-Pair-Share: Certain or Impossible?

The teacher calls out events (e.g., 'The sun will rise tomorrow', 'An elephant will fly into the room'). Students move to different sides of the room labelled 'Certain' or 'Impossible' and then explain their choice to a partner.

⏱ 20 min·Whole Class

Generate mission

Real-World Connections

Meteorologists use likelihood terms daily when forecasting the weather. They might say there is a 'likely' chance of rain or that a storm is 'unlikely' to hit a specific area, helping people plan their activities.

Game designers adjust rules to influence winning chances. A board game might have a spinner with more 'move forward' spaces than 'go back' spaces, making it 'likely' for players to advance.

Watch Out for These Misconceptions

Common Misconception

Thinking that 'unlikely' means it definitely won't happen.

What to Teach Instead

Students often see chance as 'yes or no'. Active experiments where an 'unlikely' event actually happens (like pulling the one red marble out of ten) provide a 'lightbulb moment' that unlikely still means 'possible'.

Common Misconception

Believing they can 'control' the outcome (e.g., rolling the dice harder to get a six).

What to Teach Instead

This is common in young children. Peer-led experiments where everyone uses the same 'shaker' help them see that the outcome is independent of their effort, reinforcing the concept of randomness.

Assessment Ideas

Quick Check

Present students with scenarios like 'Rolling a 7 on a standard die' or 'The school principal having blue eyes'. Ask students to write 'Certain', 'Impossible', 'Likely', 'Unlikely', or 'Might Happen' next to each scenario.

Discussion Prompt

Pose the question: 'How could we change a simple game of chance, like flipping a coin, to make it more likely for one person to win?' Guide students to suggest changes such as flipping the coin twice and needing two heads, or having a special rule for one player.

Exit Ticket

Give each student a bag with 3 red marbles and 1 blue marble. Ask them to write down: 1. What colour marble is it 'likely' to pick? 2. What colour marble is it 'unlikely' to pick? 3. Is it 'certain' or 'impossible' to pick a green marble?

Frequently Asked Questions

What are the key chance words for Year 2?

The Australian Curriculum focuses on: certain, likely, unlikely, impossible, and 'even chance'. Using these words consistently in daily conversation (e.g., 'It is certain we will have lunch today') helps students internalise their meanings.

How do I explain 'even chance' to a 7-year-old?

Use a coin toss or a 50/50 spinner. Explain that it's like a 'fair race' where both sides have the exact same amount of space or opportunity to win. It's the 'halfway' point between impossible and certain.

How can active learning help students understand chance?

Active learning, like 'The Fair Game?', allows students to see probability in action. A worksheet can tell them a spinner is 'unlikely' to hit blue, but actually spinning it 20 times and seeing it only happen twice makes the concept 'real'. It also allows for the 'surprise' of randomness, which is the heart of chance.

Is 'luck' a mathematical concept?

No, and it's important to steer students toward 'probability' instead. While they might feel 'lucky', explain that they are actually experiencing a 'random outcome' that was always possible, even if it was unlikely.