Programming A Screen Turtle

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• Computing
• Primary Education

Year Four - Programming A Screen Turtle

Lesson One

Look at the picture. Magda and Faheem wanted to go to the shop, but they ended up at the ship. Magda messaged her mum to ask for directions and they followed them exactly. What went wrong?

A

The ship was closer, so they went there instead.

B

They didn't type the message to Mum accurately. By mistake, Magda wrote ship instead of shop.

C

They changed their minds about where they wanted to go while they were walking.

D

Faheem really like ships.

Today we are learning how to program a turtle using a text-based programming language called LOGO.

It is REALLY IMPORTANT to be accurate when we are programming!

Today you will:

- Program a computer by typing commands

- Explain the effect of changing a value of a command 

- Create a code snippet for a given purpose

Good luck and have fun!

Click here to go to the 'Turtle Playground!'

See if you can find everything in the picture above.

Hint.. The online version we are using looks a little bit different!

Hint 2.. Change the dimensions (at the top) to Width 500, Height 500.

Watch the clip to see commands for moving your turtle forwards and backwards.

Watch the clip to see commands for turning the turtle left and right!

Basic commands in Logo

• FD 100 - Forward 100 (moves forward 100 steps)

• BK 100 (moves backwards 100 steps)

• RT 90 (turns right 90 degrees)

• LT 90 (turns left 90 degrees)

• CS (clear screen)

You will notice that lots of logo commands need to have a number added after a space.

For example: FD 100

The number indicates how far to move or turn.

Now it's your turn...

Open Turtle Playground (if you haven't already!)

• What happens if you type...

… FD 100?

… FD 200?

… BK 50?

… RT 90?

… RT 180?

… CS?

• How many Logo steps does it take to get to the top of your screen?

• What happens if the turtle goes off the top of your Logo screen?

• How many Logo steps does it take to get across your screen?

Watch the clip to see how to program a longer sequence.

Watch the clip to see what PU and PD do!

Your turn again! 

Open Turtle Playground (if you haven't already!)

• What happens if you type FD 100 RT 90 FD 100 all on one line?

• What happens if you change the number of steps (marked with an X below)?

• FD XX RT 90 FD XX

• What happens if you make the number of degrees bigger (marked with an X below)?

• FD 100 RT XX FD 100

• What do you think these two new commands mean?

• PU PD

In Turtle Playground, what digit would the turtle draw if you typed the following code: FD 200 LT 90 FD 100

A

8

B

9

C

7

D

3

Task - creating a code snippet

• Choose another digit and write down the commands needed to create it - use paper and pencil first.

• Use Logo to program the computer to draw the digit by following your commands.
  

• Was what you wrote correct or did you have to make some changes?

"I can program a computer by typing commands"

"I can explain the effect of changing a value of a command"

"I can create a code snippet for a given purpose"

Well Done!

In this lesson you...

Learnt the basic Logo commands and programmed the computer to draw lines of different lengths and with turns of different degrees.

Read code and predicted which digit would be drawn, and programmed the computer to draw your own digits.

Next lesson you will...

Create and test an algorithm for a program that draws your initials.