Want to understand our world better? Try a graph! You can put everything into graphs. The distance your ball travels every second after kicking it, for example. Or how much it rains every day in a year.
The horizontal x‑axis often indicates the time: for example, the seconds or days. The vertical y‑axis indicates, for example, how far your ball has travelled, or how much rain has fallen.
Sometimes x and y have an impact on each other. Then, how much y is depends on how much x is. The connection between the two is called a function. The simplest function is y = x.
An example: you get 1 euro pocket money every day. On day 1 you have 1 euro, on day 2 you have 2 euros, on day 3 you have 3 euros and so on. If x indicates the number of days and y how much pocket money you have, then y = x. How many days do you need to save for that latest game?
Graphs on your fitness app
Do you use a fitness app while exercising? Take a look at the app. You will often find graphs there. On the x‑axis you can see how long you spent exercising. The y‑axis shows your heart rate, how many calories you burned or how fast you went.
Temperature graph
Have you been enjoying those hot summer holidays over the last few years or do you hate all that huffing and puffing? Whichever it is, you’ve probably noticed that it was very hot in Belgium in recent summers. You can also see that in this graph. The temperature has already risen 2.5 °C in the summer months compared to when the measurements began.
Source: Flanders Environment Agency based on KMI (Royal Meteorological Institute of Belgium)