Preview · the opening missionRead this to the class:
A café owner serves tea at 52 °C. "Customers gulp it in the first minutes," she says, "but by the end it is cold, and I see half-finished cups." Your team's job: record three cooling curves, find how the cooling speed changes with time, and say whether a lid or a sleeve is the better buy.
Teams of three, with rotating jobs: Pourer (weighs and fills), Timer-reader (reads each cup every 5 minutes), Plotter (graphs as the data arrives).
Look inside the PDF
Sample pages, stamped “preview”. The download is the clean, full lesson.
In the full lesson PDF
- Predict (5–10 min)
- Hunt (35 min, with 30 minutes of cooling)
- Reveal (20 min)
- Act (10 min)
- Background for the teacher
- Assessment
- Student sheet
- Worksheet: Label it
- Worksheet: Try it at home
On the student sheet
- My prediction
- Our data (room temperature ______ °C)
- Graph and Newton check
- Advice for the café owner
- Exit ticket
- Label it
- Try it at home
US Letter, prints cleanly in black and white. The student sheet is on its own page, ready to photocopy.
Free with an account (any 3 lessons), or US$19 / C$25 for all 4 lessons in this unit.
What students show by the end
- Graphs and reads data
- Applies Newton's law
- Separates the routes
From the lesson’s rubric, which scores each one as not yet, getting there or got it.
Questions teachers ask
How long does “Why does a hot drink cool fastest at the start?” take?
75–90 min, or two periods (the cups need 30 minutes to cool, so graph the first data while you wait). Group size: teams of 3.
How much prep does it need?
20 minutes. Fill a HOT jug from the hottest tap, never above 55 °C (check it with a thermometer and let it cool if it is hotter), and keep it covered. Make a card lid with a thermometer hole for 2 of each team's 3 cups, and find a thick wool sock or a foam sleeve for the third. Choose a spot out of sun and draughts and note the room temperature, which is the same for all teams. Do not use a kettle in the room.
What materials do I need?
Identical plastic or steel cups, about 300 mL; card lids with a thermometer hole; wool sock or foam sleeve that fits a cup; digital probe thermometer reading to 0.1 °C, or alcohol-filled thermometer (never mercury); kitchen scale reading to 1 g (0.1 g is much better); hot tap water, no hotter than 55 °C; and 1 more. Cost: about $25 for a class of 30 if you need thermometers and cups; the scales and wool socks are from lesson 1 and home.
Which curriculum standards does it cover?
It matches Cambridge Lower Secondary Science, Stage 9 (not endorsed by Cambridge) and England National Curriculum, Key Stage 3.
What’s in the lesson PDF?
A teacher guide that walks you through predict, hunt, reveal, act, background for the teacher and assessment, then a student sheet (“My prediction”, “Our data (room temperature ______ °C)”, “Graph and Newton check”, “Advice for the café owner”, “Exit ticket”, “Label it” and “Try it at home”) on its own page, ready to photocopy. It’s US Letter and prints cleanly in black and white.
Can I try it for free?
Yes. A free account includes any 3 full lessons of your choice, and this can be one of them. After that, this unit is US$19 (C$25) for all 4 lessons, yours to keep, or every lesson is US$79 (C$109) a year.