Question

We wonder…

Will it take less effort to roll the ping-pong ball on the table, on the paper towel runway or in the lentil bucket?

Hypothesis

We think…

We think it will take less effort to roll the ball on the table because the paper towels and lentils are rough and the table is smooth so it will go faster on the table.  It will be more friction when we roll the ball on the paper towel runway and in the lentil bucket so it will slow the ball down.

Observations

We saw…

“In the lentil bucket, the ball didn’t even roll.  It’s very hard, it’s everywhere and it’s not smooth.” Odin

“I saw that in the lentil bucket when I threw the ball, it didn’t go.  It just stopped because there’s so many and it’s bumpy.”  Shayanel

“In the lentil bucket, there was friction because the lentil was kind of like a mountain going up and down.  It’s very rough, not stuck together or straight so it couldn’t go fast.”  Rusmiya

“I noticed that the ball didn’t go very fast on the paper towel runway and sometimes it came off because it was bumpy.” Noah

“When I was throwing the ball on the paper towel it slowed down because the paper towel was going up like a hill.”  Ayman

“When it was on the table, there wasn’t any friction and it was nice and smooth and fast.”  Nyasha

“When I did it on the table it was easier and faster because it was smooth.”  Erin

“When it was in the lentil box, it was so hard to roll.  I had to throw it to get it to move.  There was so much friction!”  Lydia

“The lentil box was really hard because it was bumpy and there were small seeds.  The edges made it harder to go above it.”  Rabia

Conclusion

We think this means…

We think this means that friction makes things go slow and when you use a smooth surface it rolls fast, even if you’re using less effort.  Friction makes you use more effort.

What job is the pulley doing?
How does the pulley change how we work?
If they didn't use a pulley, how could they do the job?

Ayman: "It helps us to carry so it is easy to carry the mat."

Noah: "The pulley is lifting and pulling to put the mats on the roof.  They could use the stairs but it would be a lot of effort."

Shayanel: "It's lifting a blue mat.  It's pulling it up.  If we didn't have a pulley we had to lift it up the stairs.  To lift the mats we needed 16 people!"

Lara: "It's lifting a very heavy mat.  If they didn't have a pulley they would have to carry the big heavy mats up the stairs to the roof.  That would make you use much effort."

Rabia: "The man using the pulley must use a lot of effort!"

Central Idea:  Machines are used to manipulate the world around us and alter the way we work.

Lines of Inquiry:  

How simple machines work together

Machines impact our daily lives

Ways machines alter effort


One of the best ways you can help your child in school is to talk to them about what they are learning.  This is especially important for bilingual families.  By discussing concepts in your first language children better understand the concepts at school in English.  This is also true for native English speakers, of course.

 
Our second Unit of Inquiry this year is called “Simple Machines.” Below is a vocabulary list of terms your child may be introduced to in class.  Please, DO NOT have your child look up and define these terms using the dictionary.  Instead, have conversations about the following words and concepts with your child in any language:

Pulley
Level
Inclined plane
Wedge
Screw
Simple
Machine
Pull
Force
Gravity
Work
Productive
Efficient
Ramp
Lift
Push
Compound
Fulcrum
Wheel
Axle
Effort
Load
Gear
Turn

Informal discussions at the dinner table can make a huge difference in the classroom.
 
Amy Neal
2nd Grade Learning Support