Introduction

Start in the classroom. Does anyone know what an algorithm is? It’s a series of instructions to solve a problem or task, what does that mean if we give an instruction? What makes a good or bad instruction?

 

Giving directions

Has anyone ever had to give directions to someone?  We might give different kinds of instructions depending on the type of directions we are giving. e.g:

• Where is the glue?
• How do I get to Whitley Bay?
• Where is the ICT room?

If you were directing a person, what kind of words could we use if we were going to direct a blindfolded person to help them move safely?

• Forward
• Backwards
• Left
• Right
• Side step
• Number of steps
• Turn

Ask the children to move into a large circle on the carpet with plenty of space in the middle. Place one of the hut cards at the edge of the circle and another on the other side of the circle.

Explain that you live in this swamp and want to visit your friend on the other side of the swamp, however, someone else also lives in the swamp.... crocodiles!!! Place down a number of croc cards around the carpet space.

Explain that we are going to blindfold a volunteer (that is happy to wear a blindfold) and attempt to guide them safely through the crocodile swamp without touching any crocs.

The only instructions that can be given are

• Forwards + a number of steps
• Backwards + a number of steps
• Left (side steps) + a number of steps
• Right (side steps) + a number of steps

 

 

Choose a volunteer and ensure they know their left and right. Also highlight that those giving instructions will need to think carefully about this as left and right may differ depending on where they are sitting (and the way they are facing) in the circle.

Ask the class for their instructions, one at a time. Focus on the quality of their instructions, do they make sense? are they easy to follow? will the blindfolded person know what to do? Ensure the blindfolded people only do what they have been told and don’t interpret the instructions.

Make a list of each instruction given on a whiteboard or flip chart. When the volunteer makes it across the swamp, review the algorithm they created with the class. Were they good instructions? Could we improve them? Could we reduce the number of instructions in our algorithm? Look out for repeated consecutive instructions, such as "three steps forward" followed by "2 steps forward". Show how these could be combined and replaced by "five steps forward".

Repeat with a second volunteer. Move the crocodiles and focus on the class improving their instructions based on the first attempt.

 

Paired work - Mazes

Put the children into pairs and give each pair a blindfold, paper, a pencil and a set of maze sheets (Mazes worksheets).

 

 

 

Partner A puts on the blindfold (or closes their eyes if you trust them!). Partner B must give them verbal instructions to navigate their way through Maze 1. They must not touch their partner or physically guide them in any way. Tell them not to worry if they make mistakes, just stop and correct them verbally with the next instruction. Remind them that whoever is blindfolded must listen very carefully and do exactly what they are asked to do.

Encourage them to think carefully before they give an instruction and to make it as simple and clear as they can.

When they complete Maze 1 Partner A can remove the blindfold and see how they did.  

Did you get good instructions from your partner? Why? Why not? What would have made it easier to understand?

Partner B then puts on the blindfold and Partner A gives instructions for completing Maze 2. Continue to work through the maze sheets, taking it in turn each time.

 

Plenary

At the end, discuss as a class how they found it; what was easy and difficult? How did they try and overcome problems? Did the instructions get better as you went on? How did they change?

We can also give instructions to machines. When we give instructions to a computer or machine we call it programming. This can be done in different ways to make things happen on the machine or computer. Machines only understand certain languages, just like we do. Some computer languages have to be written very carefully as computers can’t think for themselves, they just follow the instructions (like us when we were blindfolded). When there’s a sequence or set of instructions to solve a problem we can call that an algorithm.

The instructions they gave to their partner was the algorithm for getting through the maze (presuming they were correct!)