Preview · the opening missionRead this to the class:
It is the hottest week of the year, and Kofi's aunt runs a drinks stall beside the bus station. She keeps bottles of water and juice in a bucket of ice. Her helper says, "Throw salt on the ice. Salt melts ice, and melting ice is cold, so it will chill the bottles faster." A customer says, "No! If salt melts the ice, you'll run out of ice by lunchtime." Your team's job: find out which of salt, sugar or sand really melts ice fastest, and what that means for the stall.
Teams of three, with rotating jobs: Lead (handles the ice and the spoon), Timer (watches the clock), Recorder (writes, draws and measures).
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 (20 min)
- Reveal (10–15 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 results
- What we kept the same, and what we changed
- Advice for the drinks stall
- 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
- Plans a fair test
- Uses evidence
- Explains with science
From the lesson’s rubric, which scores each one as not yet, getting there or got it.
Questions teachers ask
How long does “What melts ice fastest on a hot day?” take?
50–60 min. Group size: teams of 3.
How much prep does it need?
15 minutes, plus freezing the day before: fill enough trays of the same kind to give every team 4 ice cubes, plus spares. Label 4 clear cups per team (Salt, Sugar, Sand, Nothing). Put a level teaspoon of each solid in small labelled paper cups so teams can't mix them up. Keep the ice in the freezer or a cool bag until about 5 minutes before the Hunt, so the cubes look wet and shiny (that means they are at 0 °C) and are all at the same temperature.
What materials do I need?
Ice cubes, all from the same type of tray; clear plastic cups, all the same; table salt; white sugar; clean play sand; small paper cups to hold each solid; and 4 more. Cost: about $10 for a class of 30.
Which curriculum standards does it cover?
It matches England National Curriculum, Year 4 and Cambridge Primary Science, Stages 4 and 6 (not endorsed by Cambridge).
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 results”; “What we kept the same, and what we changed”; “Advice for the drinks stall”; “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.