Heat sensitive sheets

Use liquid crystal heat sensitive sheets, either outdoors on a sunny day, or indoors with heat lamps or tubs of warm and cool water.
Science content
Physics: Heat (3)
Earth/Space: Weather, Seasons, Climate Change (K, 1, 4, 7)
  • liquid crystal heat-sensitive sheets (I get Edmund Optics 25-30 range and cut into 9 smaller squares, before laminating. Note: expensive, but last forever once laminated
  • if outdoors: full sun day, and outdoor walls, playground equipment, other outdoor objects, some that get warm in the sun
  • indoor option: heat lamps, like these
  • indoor option: tubs of water, some warm if indoors

Distribute sheets to students.

For young primaries use instead of a thermometer to measure how warm or cold water is. (indoors or outdoors)

For outdoor activity, all grades, using the sun's radiation:
Allow them to discover that the sun changes the colour of the sheets.
Give them the colour scale (for my sheets, coolest is black, then getting warmer is red, orange, yellow, blue, then black again, so black can either be coolest or warmest).
Allow students to explore the environment with their sheet.
If they need suggestions, see the photos:
block the sun's radiation with your hand/playground structure to make an image on the sheet
use the sheet to measure how warm different playground structures are
use the sheet to measure relative heat given off by differently-coloured walls
use a heat pad to change the colour of the sheet
use tubs of cool or warm water to cool and warm the sheet respectively
use drips of water to make patterns and paint on the sheet

For an indoor activity, older primaries and up, use infra red heat lamps.
Students 'charge' their sheets at the heat lamp (by radiation). Then quickly press the sheets to surfaces and objects in the classroom, where they will lose their heat by conduction.

Discuss what kinds of heat transfer heated the sheets up:
Radiation from the sun.
Conduction when the sheet is pressed against a surface or water draws heat from the sheet.

For Kindergarteners learning about temperature, they can use these in tubs of cool and warm water. Then show them a thermometer.

Use heat sensitive sheets to show how a tool like this helps us detect subtle changes in heat (show Infra red images) whereas some animals have their own sense organs which can detect these changes e.g. snakes.


Hot water bottle for charging sheets?

Need half hour to set up heat lamp charging stations for heat sensitive sheets

Grades taught
Gr K
Gr 2
Gr 3