Reading a Thermometer and Ruler - Lesson 34

This is the video for lesson 34 on my web site, Reading a Thermometer and Ruler. This is an easy lesson but it builds skills that would be important later when we have to interpret graphs and charts. Let’s take a look at this picture of a thermometer. First of all, notice that it's in Degree Celsius. In most parts of the world, they use Celsius to measure temperature but in the United States, we use Fahrenheit. Later you’ll learn how to convert from one system to other. Now, we want to figure out how high the mercury is in this thermometer. And before we can do that, we need to figure out what each of these lines represent. Now, the first thing we do is we noticed that are four lines in between the 10 and 20 and that means that there are five steps to get us from 10 to 20. If you count, you’ll see that this one, two, three, four, five. Now between 20 and 10, there's 10 degrees so we can take that 10 degrees and divide it by five, the five steps and see that each step represent two degrees. Now with that, if we wanted, we could label this 12, this line 14. I'm using opposite side it’s just that it's off to squeeze it that as much. This is 16 and this is 18 degrees. Now, we’re not done yet. We can see that the mercury is half way between the 16 and the 18, so we can just deduce pretty easily that the mercury is at 17 degrees half way between the 16 and 18. So, that thermometer is showing us 17 degrees Celsius. Let’s take a look at this diagram over ruler. First what we can see that what we are looking at here represents one inch. It just magnified very large. Now on any ruler, this is how the lines are going to look. There’ll be a long line in between each of the inch marks and that represents a half. It's halfway between the inches and that’s the longest line. Now, the next shortest line represents fourths or quarter of an inch and that makes sense because it's halfway between— in this case the zero inch mark and the half-inch mark. It's actually half of a half which is 1/4. And similarly, following the same pattern, we can see that 1/8 is half of 1/4. And continuing even further, we can see here that 1/16th is half of 1/8. The ruler can actually teach us many things about comparing fractions. For example, if we look along the top, we can see that this little line represents 7/16th, this is 9/16th. It makes sense that in between will be 8/16th and notice how that’s equal to a half as expected. If we take a look at another example, in between the 3/16 and the 5/16, we have 4/16 which is equal to 1/4 and we can continue making those comparisons. For now, I’d suggest studying the ruler. Make sure that you feel comfortable with measuring in 16 or 8 or quarters. Just make sure that you see what each line represents. This is just a very basic introductory lesson but in later lessons, we’ll work with the skills that we’ve learned in this lesson and we’ll take them to the next level.