Wednesday, August 27, 2014

STEM: Homemade Spring Scale

After playing around with our Pulleys BLAST for the past few weeks and exploring how pulleys change force we were excited to try and make our own spring scale to further explore the concept of weight and force.  We found these great instructions on how to make your own spring scale.  Jelly Bean and Jumping Bean loved playing with the store bought one we have at home, and I knew they would love to construct their own even more. I especially love the activity because it supports all the STEM activities we love.  Another great part-we had all the supplies at home already!

The first few steps were easy for the girls to do on their own.  They simply taped the piece of straw to the very bottom of the paint stick, and then glued the piece of paper directly above it.

For the next part, I had to do some of the work.  I tied one end of the string to the rubber band which was cut in half.  The other end of the string was tied to the paper clip.  Then Jelly Bean and Jumping Bean worked together to clip the rubber band to to the top of the paint stick with the binder clip.  One girls held the rubber band in place while the other clipped it on.

Next, one side of the paper clip was straightened allowing to pass it through the straw.  This was easy for both girls which made them very proud.  A hook is formed on one side of the paper clip so it can hold on to objects. 

Next, we had to calibrate the spring scale.  This was surprisingly easy.  Prior to the girls helping, I tested a few objects around the house looking for objects that weighed one ounce.  We were in luck.  Fruit snacks weigh an ounce, and we have plenty of those.

I placed a little piece of masking tape on the rope and added a dot.  This is our pointer.  Next to it on the paper, I made a hash mark and labeled it 0.  One at a time, the girls added a pack of fruit snacks and made another hash mark where the pointer stopped.  We continued until we reached the bottom.  Then, I wrote numbers down the spring scale.  There was a lot of teamwork in this step!

Our spring scale is now finished!  The girls loved making something they can play with.  Especially now that they can be little scientists on their own.  You can see Jumping Bean measuring her cup and reading the spring scale.  This went on all morning! 

I especially love this STEM activity for many reasons.  With my guidance, the girls can construct the spring scale on their own or help each other.  It is also a great way to practice the number line.  We were also able to compare objects and predict if they were lighter or heavier than another.  Jelly Bean and Jumping Bean were surprised on many predictions.


  • paint stick
  • 2 pieces of string
  • binder clip
  • rubber band cut in half
  • cup or plastic bag to hold objects in
  • paper clip
  • straw segment- about 1 inch
  • masking tape
  • scotch tape
  • piece of paper 8 1/2 x 1
  • one ounce objects- package of fruit snacks, large pink eraser, large glass stones


  1. Tape the straw segment to the bottom of the paint stick.
  2. Glue the paper strip onto the paint stick, just above the straw segment
  3. Tie one end of a piece of string to the end of the rubber band.
  4. Tie the other end of the string to the paper clip.
  5. Attach the rubber band to the top of the paint stick with the binder clip so the knot from the string and rubber band is just above the paper strip.
  6. Straighten the paper clip so it will pass through the straw segment.
  7. Make a hook in the paper once passed through.
  8. Attach a plastic bag or cup to the hook. (If using a cup, attach a string to it as well.)
  9. Place a piece of masking tape under where the rubber band and string are tied together.  Make a mark on it for the pointer.
  10. Next to the pointer, make a hash mark on the paper and label it 0.
  11. One at a time, place a one ounce object in the cup or bag and label the paper with a hash mark and 1.  Continue adding objects and making hash marks until you reach the bottom of the paper.
  12. Have fun using your spring scale!

Wednesday, August 20, 2014

Tug-of-war Advantage aka How To Pull Your Big Sister Over!

One thing that we love about pulleys is that it can give our little girls Super Strength!!   little Bear particularly loved the chance to give her sister an almost unfair fight in a game of tug-of-war and Bug loved the fact that she could match mommy (not pictured).

To set this up I gave the girls some rope and instructed little Bear to try and pull Bug (big sister) so that Bug would have to take a step.  I instructed Bug to pull back and resist her little sister but not try and pull her over.

Here little Bear was pulling and big sister just held on with one hand.   It was pretty easy to resist the little one!  So then we anchored the rope to a pillar and looped one end over a piece of PVC pipe (a broom would work as well) and repeated our instructions with Bug holding onto the PVC pipe or pulley.

Little Bear gave it her best - pulling and tugging but Bug did not move.  It did take a few tries to make sure that little Bear pulled straight and not off to the side.  Then we increased the number of pulleys or loops.  I looped the rope around the pillar and back around the PVC pipe again and repeated our instructions.  

Boy did little Bear give Bug a struggle.   Bug had to pull really hard against her little sister not to move.  It felt like little Bear was quite stronger!

We then switched around and I held the PVC pipe and Bug pulled on the rope.  At first she could not move me but I had to try hard to keep the PVC pipe in the same place when we had the multiple loops.
This was a great way for Bug to really feel how increasing the number of pulleys will change the force.


  • rope or string
  • PVC pipe or broom handle


  1. Have 2 people hold onto the ends of a piece of rope and pull like in a game of tug-of-war.
  2. Anchor one end of the rope to something sturdy like a pillar.
  3. Loop the other end over a piece of PVC pipe that one person holds.
  4. Have someone pull on the free end of the rope and repeat the tug of war.
  5. Then loop the rope around the pillar and the PVC pipe again and repeat.
  6. You can repeat this last step multiple times if you need to.


Wednesday, August 13, 2014

Pulleys: How to Make a Simple Pulley

Recently, we started to learn about simple machines and lately have been focused on pulleys.  In particular, we wanted to explore what would make a good pulley so Jelly Bean, Jumping Bean and I explored the design features of a pulley.  Based on what we learned we were able to construct an effective pulley (that is also easy to make).

First we explored the pulley shape:  we used a simple wheel to see what would happen.   To make the pulley we thread a pipe cleaner through the wheel.  We hung the pulley (wheel and pipe cleaner) from a Command hook on the fireplace, and then we wrapped a piece of string over the wheel.

The string slid right off the wheel as Jumping Bean pulled on it.  Oops, this one didn't work.

We looked at another wheel that we could use and discussed how the two were different.  The girls first noticed that they were different color, but then realized that color would not make a difference in how the pulley would work.  They also noticed that one wheel was larger than the other and thought the larger one would work better.  After talking more about the differences, Jumping Bean noticed that one wheel had sides, or grooves, on it.  Jelly Bean quickly added that the "walls" would help the string from falling off.

We attached a weight (our ballet trophy) to one free end of the string and pulled on the other.   Nope, this one did not work either.  The sides, or grooves, were not deep enough to keep the string on the pulley.  So we looked at our supplies to see if we could find one with higher sides that might keep the string from sliding off.  The girls picked a cotton bobbin.

Victory!  The cotton bobbin had grooves deep enough to keep our string on the pulley allowing Jelly Bean to pull her trophy up to the mantle!

We then talked about how we could possibly make the pulley even more efficient.   By adding a washer on each side of the wheel we were able to reduce friction between the wheel and the pipe cleaner making it easier to pull.


  • different types of wheels to test (cotton bobbin will work the best, it has deep grooves)
  • pipe cleaner
  • string
  • Command hook to attach to a ledge
  • washer- round plastic toy with a circle in the middle, real washer from tool box
  • toy
  1. Thread the pipe cleaner through the center of the wheel.
  2. Attach it to the command hook so the wheel is hanging over the ledge.
  3. Lay the string over the top of the wheel with the ends hanging down toward the ground.
  4. Tie a toy to the loose ends of the string and pull on the free end.
  5. Repeat with different types of wheels.
  6. Once you have determined which wheel works best, place a washer on each side of the wheel.
  7. Tie objects to the loose ends of the string and pull.  You have now made a pulley!

Wednesday, August 6, 2014

Exploring How Pulleys Reduce Friction

We recently started playing with pulleys and they are so much fun!!  As an adult this is my first time really playing with pulleys (all previous exposure has been theoretical) and I might be enjoying it more than the kids.

To start exploring pulleys we introduced how pulleys reduce friction.  I like this as an initial activity as friction is a topic we have visited a few times before {here and here}.  The other thing that I like about this activity is that it takes two kids working together and I always like it when the girls can learn to do something by helping each other (especially when little Bear can participate too).

First we took a long piece of yarn and threw it over the door.  Then each girl stood on the opposite side of the door and alternated pulling on the yarn.

We counted how many pulls until the yarn broke - it took the girls about 25 pulls (in comparison it took me doing it by myself about 3).  The girls battled a bit with keeping the yarn tight to ensure good friction when it was their turn to release in the back and forth.  So we worked on pulling harder and keeping it tight.  Unfortunately this meant that Bug (bigger) pulled really hard which pulled the yarn out of little Bears hands and gave her a mild rope burn.  So little Bear did not want to help much after that.  I would recommend tying something like a rod on the smaller child's side to give them a better grip and to reduce the chance of rope burn if one child does pull too hard.

We spoke about how the top of the door was rough and so there was a lot of friction on the yarn when we pulled which made lots of little cuts - like a bread knife going through a loaf of bread.  So what would happen if we make something with less friction?  To do this we made a simple pulley from a cotton bobbin and a pipe cleaner and hooked it over the door.   We closed the door to keep the pipe cleaner up.  If you find just the right spot on a cupboard door it will hold really well (as long as the kids don't yank).

The girls alternated pulling again to see if we could get to a higher number of pulls.

YAY!  We went on for a while!!  The pulley reduced the friction on the yarn when pulling.  The pulley did come off the door once when we did a really big pull but it held for normal pulls.  You may need some reinforcement if you have a child who is really excited.


  • yarn - about 8 feet long
  • door
  • cotton bobbin
  • pipe cleaner


  1. Lay the yarn over the door.
  2. Have a child hold each side and alternate pulling down.  Count how many pulls until the yarn breaks.
  3. Make a pulley by putting a pipe cleaner through a cotton bobbin.  Hook the ends of the pipe cleaner over the door and close the door to secure the attachment.
  4. Loop the yarn through the pulley.
  5. Repeat the alternating pulling on the string to see if you can get to a higher number of pulls


Friday, August 1, 2014

Ramps: Marble Roller Coaster

Jelly Bean and Jumping Bean had their first trip to a water park, and they both realized that the waterslides were like the ramps that we have been playing with.  Then, we started talking about how the roller coaster at the carnival we went to while visiting Grandma and Papa was also made of ramps.  A few weeks ago, I saw a ramp activity from Frugal Fun For Boys and so our marble roller coaster activity began!

Jelly Bean and Jumping Bean began constructing their roller coaster by taping the ends of cut off paper plates together.  They worked very well together!

Next, they used paper towel roll, toilet rolls, and blocks to support the ramp.

Our first attempt at rolling the marble down the roller coaster was not a success.  The marble rolled right off the side at the first turn.

After talking about the slides at the park, waterslides at the waterpark, and roller coasters, the girls came to the conclusion that they all have sides.  We tested the roller coaster again to see where the marble went off and put sides on.  And success!  The marble ran down the roller coaster without falling of the side.

Jelly Bean and Jumping Bean did quite a bit of work on our roller coaster, but this activity definitely required a lot of my help.  They loved how we were all thinking together to come up with solutions to our problems.  I loved it too!  I could really see their thought process and how they were able to bring in prior knowledge to help construct our roller coaster! 


  • paper plates
  • toilet rolls, paper towel rolls, blocks
  • tape
  • scissors


  1. Cut the bottom off of a paper plate (use the decorative plates that have ridges on the bottom).  I got mine from The Dollar Tree.
  2. Make one cut in each circle to open the circle.
  3. Tape one end of a cut circle with one end of another cut circle creating a twisty ramp.  Connect as many as you would like depending how larger your roller coaster is.
  4. Tape the rolls to the bottom of the ramp at different leaves creating a roller coaster.
  5. Cut smaller pieces from the cut circles and tape them around the curves of the roller coaster.
  6. Place a marble at the top and let it roll down to the bottom.