Session 1

Unplugged algorithms for moving along a route


• Understand that an algorithm is a set of instructions in a particular order
• Create a set of instructions to navigate a simple route, using forwards, left and right commands
• Follow a set of instructions accurately
• Record instructions accurately
• Print and cut out van cards and arrow direction cards from printable assets
• Resource sheets 1-3 (enough for each pair to have two sheets)
• Resource sheet 4, with van card cut out and stuck on to a cube (e.g. Dienes unit)
• Instructions, sequence, algorithm
• Forward, backward, right, left, corner
• Route, journey
If working with a large group, you could make a large grid mat and print a large version of the van onto card. Attach the image of the van on top of a toy car so that it can easily move around the grid.

Let's get started

Talk to the students about delivery vans. Have they seen any? (Royal Mail, DHL, Ocado etc...) In this project they are going to control their own van on the computer. They will control the van by giving it instructions to move. Very clear instructions.
Explain the learning expectations and that they will be computer programmers, but before that they will look at a model of a van on a tabletop map to think about how to give it clear instructions.
Demonstrate how the van travels along the road on resource sheet 1 [fig S1.1].
What types of movement is it making? (e.g. moving forwards, driving around a corner)
If we are going to give exact instructions, what might those instructions be?
If we just say go forward, exactly how far forward do we mean?
Guide the discussion so that the students understand that ‘drive forward one grid square’ is more precise than ‘move forward’, and that ‘drive around the corner to the right’ is clearer than ‘go that way’!
Explain how the students are going to use the arrow direction cards [fig S1.2] to use them to record their instructions. Explain that the rules for this van are a little different from a BeeBot. Forward means one grid square from edge to edge. Turn right means drive around the corner to the right from edge to edge [fig S1.3].
fig S1.2
fig S1.3

Explain the activity

Sitting on the floor, ask one student to move the van card and say the instruction that is being followed e.g. forward. Ask another student to choose an arrow direction card to record this.
Demonstrate this step-by-step, so that you end up with a short sequence of arrow cards.
fig S1.4
Get the students to say the sequence out loud [fig S1.4]. If some students are having difficulty distinguishing left from right, try using the Left and Right van cards in the Assets file.

Key questions

Does it matter in which order we give the instructions?
What would happen if we mixed them up?
Explain that a sequence of instructions in the correct order to drive the van from start to finish is called an algorithm.

Paired activity

Give each pair of students resource sheet 4, a van card and a set of arrow direction cards to record the route. One student can be the ‘driver’, one can be the ‘tracker’.
Explain that the ‘driver’ takes the van from the start point to the finish point, and tells the ‘tracker’ what each instruction is. The ’tracker’ records the journey using the arrow cards.
Change roles, repeat activity.

Mini review

Bring the group back together and ask one pair to show their route and instructions. Ask another student to test out the instructions by following them from the start point.
Demonstrate how they could record this on a mini whiteboard instead of using the cards.
Give each pair a chance to do the same activity with the next grid route, this time recording the movement on their whiteboards or on Resource sheet 2 to Resource sheet 4 [fig S1.5], drawing their own arrow instructions, or if they prefer, using F, R and L.
fig S1.5