This type of activity is known as Demonstration. Please read the guidance notes here, where you will find useful information for running these types of activities with your students.
1. Demonstration
- I begin by displaying the Desmos page with none of the equations selected (just click on the coloured squiggle to the left of their equation to revel or hide the line)
- I ask my students to consider what the first equation will look like when plotted. I ask them to visualise this first and then sketch it on one of their blank girds (see below) marking on any points of intersection with the axes. They can show this to their neighbour, compare answers and discuss.
- I then reveal this equation and ask students to reflect on their visualisation and sketch. I will ask if anyone drew something different, so we can tease out and discuss any miconceptions
- I then ask students to predict (and then sketch) what the second equation will look like, asking them to reflect on what has changed and what has stayed the same
- I then reveal the second equation, and ask students to reflect on their prediction. Again, this is a key discussion point, with students sharing their reflection with their neighbour, and then with the whole class. I will ensure that attention is drawn to the critical aspect of the question that changed.
- I then hide the first line and ask students to predict what the third equation will look like
- I continue this process, always having two lines visible at any one time
- When appropriate I will ask “which other equation(s) had a graph that looked exactly like this?”, and reveal earlier equations as and when needed
This is the sequence of lines that I use:
Here are some blank axes for students to make their sketches on:
2. Possible variations
- Vary the coefficient of x
- Vary the intercept
- Change x to x²
Click here to access the Desmos file
3. Downloadable version
- Worksheet from Pixi Maths: Sketching Straight Line Graphs