Session 4 - Different types of loops

Objectives

• To look at different types of loops: counted loops (repeat a number of times) and indeterminate loops (repeat until and repeat while)

Resources

Resources

• Levels 29 to 32 in Rapid Router

• Video about repeat until and repeat while: https://youtu.be/EDwc80X_LQI

• One printed copy of the worksheet per group. Digital version for display on the IWB

Keywords

• repeat until

• repeat while

• repeat n times

Lesson guide

Introduction (10 mins)

1. Introduce level 29 on the IWB and ask pupils what they think repeat-until will do; point out the at destination block if necessary

2. Ask a volunteer to test this out with this simple route. Solution:

3. Do this again with level 30

4. Show video about repeat until and repeat while

Mini Review (5 mins)

1. Ask the pupils to discuss with their partner the difference between repeat until at destination and repeat a number of times – write this as a question on the IWB

2. Ask pupils what answer they came to

Paired Activity (25 mins)

1. Pupils complete levels 29 - 32 in pairs

2. Pupils who finish can do a random level in the 29 – 32 set. (Click quit, open the 29-32 set, then click random level)

3. Hand out copies of the worksheet

4. Demonstrate how the grid should be filled in (pupils often do not use the grid squares) but do not show any part of the solution

5. Ask pupils to draw the route where repeat until at destination would work

6. Pupils discuss the activity in pairs

7. Draw a solution on the IWB and ask who had a different answer. Is there more than one correct answer? Why?

8. Pupils should hand in their solutions to the teacher

If pupils finish these activities before the end of the session, allow them to do random levels in the Loops with Conditions section.

Share and Review (10 mins)

• Explain that next time you are going to look at Loops with conditions.

• What did pupils find difficult?

• How did they solve their problems?

• Recap on the keywords