Mathematics K–6 · Years 1–2
Will it happen: chance words and ten coin tosses
Statistics and probability
The idea
Some events are certain, some are impossible and some might happen, and a coin toss is an event that might go either way every time.
What you need
- 12 event cards (the sun will rise tomorrow, a fish will fly to school, it will rain today, I will roll a 6)
- three labels: will happen, might happen, will not happen
- a 20 cent coin per pair and a recording strip of 10 boxes
How to do it
- Sort the event cards under the three labels. Explain each choice to a partner and move any card you disagree about after discussion.
- Predict what will come up if the coin is tossed: heads, tails, or cannot tell.
- Toss the coin 10 times, recording H or T in each box. Count the heads.
- Compare your count of heads with the other pairs in the class. Write the smallest and largest counts on the board.
- Toss once more and say before it lands which side it will be, then check. Discuss whether anyone could be sure.
What you should see
Cards such as the sun rising go under will happen and a flying fish under will not happen, while rain today and rolling a 6 go under might happen. Ten tosses give different head counts across pairs, most between 3 and 7; with a fair coin the chance of a count between 3 and 7 is 0.89, so in a class of 12 pairs, on average 12 times 0.11, about 1.3 pairs, get a count outside that range. Nobody can predict a single toss reliably, and the class sees this from the mix of right and wrong calls.
What changes
This activity lists no variables to change, measure and keep the same.
Common misconceptions
Each of these ideas is wrong, and the activity is a chance to test it.
- After three heads in a row, tails is now more likely.
- Might happen means it will happen about half the time.
Safety card
Hazards
- coins are a choking hazard for very young children
Controls
- supervise and collect coins at the end
Note
No chemicals or heat are used, so the NSW Department of Education Chemical Safety in Schools package is not needed; ordinary classroom supervision under the school's usual risk management.
Curriculum references
The NSW syllabus outcomes and Australian Curriculum v9 codes this activity supports. They are references, not a verified or complete curriculum alignment.
- Mathematics K-10 Syllabus (2022), NSW Education Standards AuthorityMA1-CHAN-01MAO-WM-01
- Australian Curriculum v9No Australian Curriculum v9 code is listed.
Sources
The pages the author read to write this activity.