Get a great visual view of the temperature outside with a glass Galileo Thermometer for the garden These beautiful thermometers work through the principle of relative density and they've been around for a long time to let us see what the temperature is without mercury. The smaller 57cm thermometer includes 12 glass balls and has a range of 16C to 38C while the larger 71cm thermometer includes 13 glass balls and has a range of 16 to 40C. When the temperature outside changes, the relative density of the balls in the tube changes which causes them to rise and fall in the liquid. The ball that settles in the centre of the tube indicates the current temperature - it's beautifully simple and a science experiment you can look at every day These outdoor Galileo thermometers come with a black metal frame and hook. Hang your thermometer on a plant hook or loop it through a wire fence, then sit back and watch the temperature change Put your Galileo thermometer on the porch near the door so you can see the outside temperature from inside the house Galileo Thermometers for the garden make wonderful gifts for your friends and family who love to spend time outdoors in the yard or on the porch. Order today for your dad or husband to give to them for Father's Day or his birthday Product Specifications: 57cm thermometer includes 12 glass balls, temperature range 16C to 38C 71cm thermometer includes 13 glass balls, temperature range 16 to 40C Includes black frame with hook Not a toy, keep out of reach of young children and animals