Contact Forces

SEEd: Investigating Forces- Lesson 3

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Investigating Forces

Core Knowledge Science-- 3rd Grade

​Let's Do a Quick Review on What We Have Learned So Far...

Multiple Choice

When you push or pull something, you are creating_________________.

• weight

• a speed

• a force

• a surface

Multiple Choice

A force can____________.

• make an object move

• make a moving object stop moving

• slow an object down

• all of the above

Multiple Choice

True or false: An object resting on the ground can move without force.

• True

• False

Multiple Choice

What will happen to the book if no other forces act upon it?

• book will stay at rest

• book will begin to move

• mass of the book will increase

• gravity on the book will increase

Multiple Choice

If you have balanced forces on a ball what happens?

• It stays still
• Keeps going
• :(
• :)

​The BIG Question!

​How do FORCES affect the motion

of objects?

​Vocabulary

• ​balanced forces: a collection of forces acting on an object that cancel each other out and produce no change in the object’s motion

• ​predict/prediction: to say that something is expected to happen

• ​unbalanced forces: a collection of forces acting on an object that result in a change in the object’s motion

Hands-on Activity with FORCE!

​Try this...

• ​​​Place an eraser on a flat surface

• Apply PUSH & PULL forces to the eraser

• ​Which DIRECTION did the eraser move when I pushed on the eraser?

• Which DIRECTION did the eraser move when I pulled on the eraser?

• ​Were the forces acting on the eraser BALANCED or UNBALANCED?

What did you LEARN?

• ​FORCE is the CAUSE

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• MOVEMENT is the EFFECT

​WATCH this video: Balanced vs. Unbalanced Forces!

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What QUESTIONS do you have about Balanced & Unbalanced FORCES?

​Meet with your group to come up with a SPECIFIC QUESTION!

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DO Activity Page 3.1 :)