Hot and Cold: Particles on the Move

Why tires go soft in January, why sidewalks have gaps, and how a thermometer knows. Five lessons on what heating and cooling do to the particles in everything around us.

Lessons in this unit

1Why do bike tires go soft in winter?Students stretch a balloon over a bottle, move it between warm and ice water, and find out what happens to air particles when they cool down. Then they explain a cyclist's 'flat' tire on the first cold morning.Sample lesson
2Why does food colouring spread faster in hot water?Two cups, two drops, one race. Students watch particle motion they can't see, and design a fair test to prove it.Coming
3How does a thermometer know?Teams build a working bottle thermometer from coloured water and a straw, then calibrate it against a real one.Coming
4Why do sidewalks have cracks on purpose?Expansion and contraction in bridges, sidewalks and power lines. Students hunt for the gaps engineers leave and explain why.Coming
5Can you keep an ice cube frozen the longest?A design challenge with insulation, a timer and a class leaderboard. Optional: log the temperature inside each design.Coming

This is our pilot unit. Pilot teachers will teach it in January 2027 and tell us what to fix before we mark it classroom tested.

Every lesson uses things you can find at a dollar store or in the staff room. The last lesson has an optional extension with a temperature logger.