• Can then be used to indicate the level of butane or propane in a gas canister, or the level of foam or water in fire extinguishers
• or anything where a temperature differential is created on the outside of a vessel containing a liquid
• Heat the strip and watch for the colour change from black to a bright orange. Student and Teachers Learning Resource for Education
• Self-adhesive backing and a polyester protective film. Dimensions: Approx. 190 mm x 20 mm wide
• place the strip vertically down the side of the cylinder or canister, then apply heat (See description)

LIQUID LEVEL INDICATOR STRIP This versatile strip utilises smart materials with thermochromic properties to determine the approximate difference in temperature between two areas. As such, this can then be used to indicate the level of butane or propane in a gas canister, the levels of foam or water in fire extinguishers or anything where a temperature differential is created on the outside of a vessel containing a liquid. The strip has a self-adhesive backing and a polyester protective film. It measures approx. 190 mm x 20 mm wide and can be out to length to tit most sizes of canister. The colour changing process reverses back and therefore can be used numerous times providing it is not exposed to excessive temperatures. To determine a level simply place the strip vertically down the side of the canister, then apply heat to the strip using a heat gun or hair dryer until the strip has completely changed from black to a bright orange. (Very hot water can be used as an alternative under supervision). Once the heat source is removed a portion of the strip will change back to black faster. The line created by the difference in colour indicates where the approximate level is. The product here is demonstrating thermal conduction and the principle of a heat sink. It can also be used to check the level of gas in a cylinder by connecting to an appliance. If the appliance is used to burn the gas for 5 minutes and the above technique followed once again, then a more accurate level may be determined for the gas, as the liquid and the gas above it will no longer be in thermal equilibrium. The unit is designed ideally to work in ambient conditions between 14 to 40°C. It cannot take a reading if placed entirely within the area of the gas level or entirely within the vapour level.