Sam's New Dog

Sam’s neighbors have decided to move and Sam is very sad. His best friend, after Sara of course, is Buddy, the dog from next-door. Buddy is the cutest little puppy with big, funny eyes and Sam often takes Buddy for walks and they play together. This is going to change now that Buddy is moving!
Sara feels very sorry for Sam and decides that she wants to cheer him up and get him a new dog friend with funny eyes to play with – a friend just like Buddy.

Can you help her build a Buddy-look-alike with big eyes that move?
Let’s find out!

Build Sam’s new dog using building instructions no. 8.

• Place the eye disks on the axles as shown
• Each of the axles should spin smoothly
• If not, just loosen the yellow pulley wheels so they do not rub on the red beam

Same or opposite?
By turning the nose you can make Sam’s new dog’s eyes rotate. Find out which of the pulley belt settings will rotate the eyes in the same or in opposite directions.

First predict which pulley belt setting will make the eyes rotate in the same direction and which will make the eyes rotate in opposite different directions?
Write down your predictions using the words on the worksheet.

Next, test the two pulley belt settings.
Write down your findings using the words on the worksheet.

Have the students reflect on their tests by asking questions such as:

• What did you predict would happen and why?

• Describe what happened.

• How did you make sure your tests were fair?
  Was the pulley belt adjusted correctly?

• Describe how the model works.

Same or different?
Change the pulley belt settings and you can change speed at which Sam’s new dog’s eyes rotate. Find out which of the pulley belt settings will rotate the eyes at the same or at different speeds.

First predict which pulley belt setting will make the eyes rotate at the same speed and which will make the eyes rotate at different speeds?
Write down your predictions using the words on the worksheet.

Next, test to see if the result supports your prediction.
Write down your findings using the words on the worksheet.

Optional: Dress up Sam’s New Dog
Dress up Sam’s new dog to look nice, sweet or cool.
You may want to make ears, a tongue and even a tail using a variety of materials such as cloth, paper, etc.