Reading a thermometer to determine the temperature requires specific math skills. As children learn the math principles of a line graph, counting by increments other than ones and rounding, they become ready to learn how to read temperature. Encourage an interest in daily weather conditions and the temperature outside to teach children how to read a thermometer. With daily practice, children can become adept at determining the temperature and reporting it to you.
Teach children how to count by twos, fives and tens by counting together in these increments. Start with tens, then move to fives and finish with twos. Practice this counting every day to help children become comfortable and skilled at this incremental counting.
Present a line graph to children. Make the first line graph simple with a horizontal line and vertical lines denoting zero through 10. Help the children understand that the zero line is the first line on the left because it represents the smallest number on the line graph. Show the children that the 10 line is the last line on the right because it represents the largest number on the line graph.
Show the children basic rounding techniques for working with numbers. Use the line graph from Step 2 and show the children how numbers between zero and four round back down to zero and numbers between five and nine round up to ten. Expand the rounding principle to include numbers above 10 when the children demonstrate understanding of the basic rounding principles.
Present the outdoor thermometer to the children and compare it to the line graph. Show the children how the thermometer resembles the graph, except instead of it being horizontal it is vertical. Draw attention to the zero line on the thermometer and show the children the larger lines above the zero line that represent each -12.2 degrees C. Show the children the smaller lines between each 10-degree line and tell them that each smaller line represents 2-degree increments between the 10-degree lines.
Show the children the red line of mercury going up the centre of the thermometer. Demonstrate how the red line can correspond to the nearest line that will denote the current temperature. Tell the children that lower numbers represent cooler temperatures and higher numbers represent higher temperatures. Tell the children that the red line goes up when the temperature rises and it goes down when the temperature drops.
Set the thermometer in a place where the temperature will vary each day. Practice reading the temperature at least once each day. Utilise the children's rounding abilities to round the temperature up or down according to where the red line reaches on the thermometer. Show the children that if the red line falls between two lines, they can figure out what the actual temperature is by figuring out what number falls between those two number lines on the thermometer.
Teach the children the freezing and boiling points in both Fahrenheit and Celsius. Briefly touch on the difference between Fahrenheit and Celsius temperature scales and show the children that some thermometers have both Fahrenheit and Celsius temperature scales on them.
Have a mercury spill kit in the classroom. Warn the children that if they accidentally drop the thermometer, they should not try to clean up the mercury themselves. They should call you (as the teacher) for help.