Kindergarden science - Paper Cogs

Cogs are a corner stone of mechanics. Although they are rather simple to make they tend to have a low tolerance to faults. The key to getting something that works in the end is to measure them as precise as possible at the start.

Stage 0) Adult prep
You can look below to construct the cog pattern from scratch or you can print out 2 patterns and paste it on to the cardboard.

Stage 1) Create some interest
Ask your kid about a clock(one with the cogs showing is best) how it turns and works and show her pictures of the insides. Ask her if she wants to make some cogs.

Stage 2) Gather materials
Get the cardboard with the cog patterns on it. Get scissors tape and a sharp pencil or Japanese chopsticks.

Stage 3) Cut it out.
Cut the cogs out. Don't worry to much about being too precise, just get them to follow the lines. My daughter was able to cut it quite neatly when I showed her to cut straight lines, even despite the cardboard thickness. Also clip the points of the teeth so they are flat (the points are weak and will easily get jammed). Cut a long strip of cardboard as the backing to the cogs. Then the adult should cut 2 cardboard pins(shown on the pattern) from the left over cardboard.

Stage 4) Assemble.
Place the two cogs on the backing board. The teeth should inter-mesh with about 1-2mm of gap between the two cogs. Then with Japanese chopsticks or a sharp pencil punch a hole in the middle of the cog and though the backing board. Push in the cardboard pins and fold them over on the backside and tap them to the backing board.

Stage 5) Test
Spin the cogs and check that they work correctly. Draw arrows to show (and discuss) how the cogs turn around.

What they learn

• Basics of mechanical devices
  
• Basics of rotational dynamics
  

Appendix
How to construct the Cog pattern from scratch.

0.1) First create a compass. Tape 3 sharpened pencils together in a triangle with of the 2 leads about 5cm apart.
0.2) Get some thick cardboard, thicker is better.
0.3) Draw a circle with the compass.
0.4) Then rule a straight line through the center of the circle, using the edge of the ruler to measure the 90 degrees draw a second line through the center to form a +.
0.5) Where each of lines touch the circle place the compass point and draw a lines marking the circle both above and below. These marks are exactly +/- 60degrees from the line. Once finish you will have marks on the circle at every 30 degree(including the + lines). There should be a total of 8 points marked and 4 points where the lines cut for a total of 12.
0.6) Now take the compass again an draw a circle around to of the neighboring marks. The two new circles will cross at 2 points, 1 the center of you main circle and another point outside of the circle. Draw a straight line through the 2 points where they cross. This forms the 15degree mark on the circle.
0.7) With the ruler place the corner of it on the 15 degree line facing into the main circles middle, and with the sides touching the marks on the outer circle. Trace its edge.
0.8) repeat for other 11 marks.
0.9) repeat for another cog.

Sounds complex but its quite simple to do.

Kindergarden science - Shaky leg robot

The Shaky leg robot is a simple device that uses mechanical vibration to draw random lines and patterns.

Stage 1) adult prep
Scavenge a battery container, switch and motor from a broken toy or device. wire them together and check the the switch correctly operates the motor. tape the motor to battery pack so the shaft extends out. tape the switch so is faces in the same direction but on a neighboring face of battery case.

Stage 2) build interest
Discuss robots and what the are with you kid. Ask if she wants to make one.

Stage 3) gather materials.
Get an old box with about 15cm square of thick cardboard.
Get the scissors, tape and 4 crayons

Stage4) build it - child
Cut about a 3 cm line straight in about 3cm fold the edges up and tape the overlapping 3 cms to the next edge. this forms a kind of strong small shoe box top.
tape the motor to the inside of box lid with the drive shaft out.
tape the four crayons/texters to the four box lid corners so they point in the same direction as the motors drive shaft and extend as far as possible.
then tape the weight to the motor with a long piece of tape

Stage 5) turn it on and test - done by child
Stand the entire device on a sheet of paper so the the points of the crayons are touching the paper. and turn it on.

The weight should swing around between the crayon legs causing the whole thing to shake and rotate drawing lines in the paper.

Have your kid change the length of the tape between the weight and motor and crayon leg length and see what happens to the drawing. Ask which is better and why

What they learn

• basic engineering; prototyping and refinement
  
• structure and stability (odd sized legs)
  
• the basics of mechanical vibrations what the are and why they exist
  

Refer: http://www.newscientist.com/article/dn19501-homebrew-technology-meet-new-scientists-junk-robot.html

Kindergarden science - Biology

My young daughter has reached 4 years old and I have decided its time to get her started with some basic science. Everyone knows about the classic carrot-top in a dish experiment. So here is the recipe for it;

Stage0) Adult basics.

• Young kids learn alot by mimicry
  
• How you act and react will directly teach them. More than what you say about it
• They will learn good scientific procedure if you show them it rather than tell them it
• Young kids have an very short attention span about 15mins max.
  
  • Experiments need to have simple easy to understand objectives
  • You must prep the materials before hand or the child might wander off or lose interest before its ready.
  • Experiments need to be piece wise if they are long, take a break if its too long and rekindle your kids interest
  • Experiments need to have a fascinating or intriguing result.
  • Sometimes things go wrong or you get stuck it is best to get the kid of on a side project while you sort it out or risk them becoming confused and frustrated as you do.
• You dont want kids handling dangerous stuff, but you want the child to learn enough practical caution
  
  • For example using scissors is ok, but using them badly or in a way not intended will teach your kid to do the same.
  • With chemistry experiments think food science, if it cant be eaten or goes boom then its most likely not suitable for a young kid.
    

Stage 1) Create some interest (And adult prep)
Take a carrot, and cut of the top(about 1 cm thick) and take it to your kid. Ask her what it is what she thinks about it. Ask her where it came from and how it grew up to be a carrot. Explain to her the that the carrot is still alive even now and we can make it grew again. Ask her if she believes it. Ask her if she wants to see it happen.

Stage 2) Prep the experiment(done by your kid)
Gather the materials, A plastic container, cup of water, the carrot top, and a piece of paper(the less the bleach and artificial coloring the better)

Stage 3) Experiment(done by the child)
Place the paper in the container, add the carrot on top, poor on the water(about 1/3 of the carrot should be underwater) and place near a sunny window. Go play elsewhere

Stage 4) Measure and discuss(done by the child)
Come back every day with a log book, ruler and pencil. Ask her about what has changed and measure how long the new green sprouts and roots are. Write it down in the log book. Then after a week create a graph and play connect the dots with her.

Stage 5) End the Experiment(done by the child)
After a while this will start to get monotonous and the fascination will end, it is best not to kill your kids enthusiasm by over doing it. My daughter choose to end this experiment by feeding the new carrot sprouts to a rabbit.

To sum it up you have exposed your child to;

• Basic experimental procedure
  
• Measurement and logging of results
  
• Basic charting
  
• Basic biology; What are Roots, What are Leaves, What are Stems
  
• Basic biology; Planets grow slowly and fresh veggies are alive
  

http://www.dummies.com/how-to/content/plant-biology-roots-shoots-stems-and-leaves.html