Engineering Archives - Go Science Girls

DIY Robotic Articulated Hand

November 7, 2019November 7, 2019 by Angela

Let’s make an articulated robotic hand that can be controlled with kid’s finger movements.

This is an activity that will describe the finger movements to kids with an easy explanation. You can also try this at home with kids. We have uploaded step by step demonstration for your easy reference.

How it all started?

My younger kid is very naughty and once she playfully closed the door when my elder one was keeping her hands in the closure. Her fingers got caught and she had pain. It was not very harsh though so I managed to keep ice cubes to relieve her from pain. At that time she was asking me about how the finger bends and why thumb finger has only two partitions while others have 3 etc. To cut the story short, these questions inspired me to teach her the anatomy of fingers with a DIY experiment.

Things required for making articulated hand

Before we talk about science, let us first see how to make this articulated hand model using simple things available at home. We bought few things from our local store. But, we have provided some links for your reference which you can refer to order online.

Cardboard – To trace and make the hand base
Beads – For decorating at the fingertips
Pen – Trace the hand and fingers
Scissors – For cutting
Sticky tapes – To hold the joints, etc
Straws preferably paper straw – To allow the twine to pass through and imagine straws as bones
Yarn or twine – These allows fingers to bend and will act as tendons
Glue gun – For pasting purposes
Ruler – To make bends at the joints of the finger

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Steps for Making Robotic Articulated Hand

Step #1: Tracing and Cutting

Trace the hand on the cardboard by placing the hands on it in such a way that the fingers are facing you. Cut the outline and refer video to know how much tracing is required.

Step # 2: Bending the cardboard to make fingers

Use a ruler and bend places on the finger-like we bend our fingers. There are three lines in each finger and bending is complete in the portion where the fingers and the palm are connected. The next line also fingers bend thoroughly except for thumb finger. The topmost line in the finger bends partially. Make sure you check this action so give a perfect movement to your articulated fingers.

create tendon bends in cardboard articulated hand

Step #3: Straw cutting and pasting

Cut the paper straw into small pieces to make fingers with bones as well as tendons. Cut them small and place them in between each bend you just made. Remember the twine will pass through this straw and make the movement of the fingers possible. So place straw pieces in equal distance.

The straw will act as bones for fingers and twine as the tendons.

Note: You must make sure to give a gap between each straw and that is the best way to let the fingers bend flexibly. Also, do not tighten too much which will make it rigid and the hand anatomy will not be reflected properly.

Step #4: Pass the twine and tie beads

Cut strings into pieces and for length refer to the video. Tie the beads to the string pieces and 5 beads are required for one finger. Connect them with the straw to the thumb and other fingers too. However, beads are optional. You can skip beads and pass through twine in the straw as we did as well.

Ensure twine length and give enough space to allow it to move.

pass twine and tie beads to form nerves robotic hand

Step #6: Make a handle

Holding will become simple with the help of this cardboard cutting. Fold them and use glue gun to fix the handle. You must cut it that way and fix your hands inside.

Finally we used pipe cleaners to create rings for each finger and attached them to the twines. You can use actual play rings if you have.

It is over and the hands are ready to make any movement. You can hold things, play with the gun and much more.

Paste straws with the glue gun and allow it to try so that it is fixed correctly.

I let the girls have fun for some time. Then we are ready for our final bit.. now that we made bones, tendons and nerves, why not we add flesh to make it look like a real hand.

My elder daughter suggested we should try inserting this hand in a glove to see whether it looked like a real hand.. Here is how we tried it..

Since we used cardboard, it was bit difficult to get it inside the glove. But we finally succeeded with few extra folds in the cardboard. That made the hand more flexible and less sturdy. But we could still use it to make finger movements.

Science Behind Articulated Hand

Every finger has three bones whereas thumb has only 2. We call these bones as phalanges. That is why there are two lines in the thumb and three for other fingers to separate each small bone. We have straws to show them externally.
These phalanges will connect to the five bones present in the main portion of the hand. That is named as metacarpals. (You can find 8 bones in the wrist which are called carpals, but we have not shown that in our handcraft.)
The forearm contains the muscle which actually moves the thumb and the fingers.
Long flexor tendons are the one that extends from the forearm muscle and passes through the wrist as well as the palm to the thumb and fingers.
Tendon sheath is the place where the tendon slide and this passes through a snug tunnel. This is attached to the small bones of the thumb and other fingers. The tendons are held in place with the help of these sheaths. Contraction of forearm muscles will pull the tendons and thus the bones are moved.

Since the tendons are linked to the fingertip from the forearm, whenever there is minor damage in tendon it will affect the entire finger. I explained this to my kid and hence she suffered pain when the door slashed on her fingers.

The hand contains the veins and the arteries where the blood flows from and to the fingertips. The nerves present will let the feelings happen when you touch something with the fingers and hands. Indeed hands make a vital part of our body. These nerves are represented by the twine that forms the fibrous tendons.

Suitable For

It is a tricky activity but aptly suits 5+ years kids. We must provide help to them to make it work properly. However, 7+ kids can do it on their own.

For kids above age 8 can understand the anatomy and so teach in detail about the finger science.

Word of Caution

When you make this articulated hand activity with cardboard you must be around as they need to use scissors to cut them. Cutting the cardboard can be tricky so my husband helpedme out. I would suggest you cut it for them to avoid any injury.Glue gun end point is pretty hot and avoid keeping near children. Alternatively, you can use double side tape like this one just to be safe.

Try this DIY and share your feedback for improvement. Trust the video helps you make a hand model at ease. Refer this link for better understanding in case you wish to go in-depth about hand science to kids.

Disclaimer : This post contains affiliate links from Amazon. An affiliate link means that when you purchase using the link provided in this page, I would get a small referral fees WITHOUT any extra cost to you. I highly appreciate your understanding and support.

Build Your Own 3D Structure : STEM Challenge for Kids

August 10, 2019July 3, 2019 by Angela

As a parent, I need to think in every possible aspect to enhance my kid’s thinking ability and especially on how to improve their STEM future. So, this time I have picked ‘Building 3d structures and shapes’ to teach my children through a couple of hands-on activities. Check this to see how we did a catapult last week.

As we all know, kids show much interest on visual part rather than listening to something as lecture. So, I want my little ones to learn the dimensions of 3d structures by performing some simple and fun activities that involve both kin-aesthetic and visual elements which takes major role to make learning last lifetime.

In the below mentioned activity, children will get to know and learn about simple and easy instructions to make 3d shapes in a fun way using commonly used materials nothing but kids beloved play dough and few sticks. Also, this activity keeps children engaged and active in their free study time. It may even challenging to build and understanding the concept of making and identifying the faces, edges, and corners of different 3d solid shapes.

I made up my mind to choose one as per my elder daughter Pritika’s interest. She is 5+ years old and did not want to disappoint her by choosing any difficult task. My younger one, Tisha started clapping while arranging things required for the activity on the table. 🙂

Before we start teaching our kids about 3d shapes, make sure your kids are familiar with the 2d shapes as well. If not give them a brief explanation or visual orientation on 2d shapes which helps to better understand the 3d shapes easily (check Jamie’s abacus page for handmade crafts for kids).

Suitable For

This STEM challenge is good to go for young kids around 5-6 years old. There are others to different age group. Try out different 3D structures like Pyramid or Trapezium for older kids, to challenge them even better. This can help your child develop critical thinking. For example, they can construct a 3D structure with weight bearing capacity. Or a taller structure etc. Explore building the 3D structure with different objects as well.

Materials required to make 3d Shapes Stem Structures

Generally, people wonder how to explain 3d structures to kids without leaving any confusion in their minds. But our simple materials that are available in everyone’s home made it simple to perform this activity of teaching 3d structures to kids in a very fun way. Let us see what they are!

Play Dough (You can use different colours and shades of dough to make the activity colourful and interesting)
Sticks (Different sized Sticks are used to make different dimensions of 3d shapes)

What!! Surprised!? Yes, absolutely, that’s it…..we need only a couple of things to execute this super fun activity.

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What are the steps required to keep the things ready before starting doing 3d shapes

Step-1:

Firstly, I asked my elder daughter to spread a big white sheet on the working table. Why white!!? Since we are using different colours, the white background helps the kids to have a clear vision and also to observe the shapes and dimensions made of a variety of colours without any confusion.

Step-2:

Ask again your kids to do small balls out of their favourite coloured play dough and keep it aside. If the play dough gets dry, you can tell your kids to wet their hands with the water to keep its moisture maintained.

Step-3:

Now let the kids cut the long sticks into different sizes and lengths. Make sure to keep a few sticks of same size.

How to do the 3d shapes

Now, we have everything ready to do 3d shapes. Here, you can ask your kids to name some of the 3d shapes they know. You can show them different types of 3d shapes to give them an idea prior to begin the activity. Without the knowledge of 3d shapes, it is waste of your and your child’s time to do this activity as they don’t understand the main concept of understanding 3d structures.

What is the definition of 3d shapes?

In a simple language, 3d shapes are three-dimensional structures or the shapes that have three dimensions. For example, sphere, cube, pyramid (triangular and square), prism, cone, cuboid, and cylinder are some of the basic 3d shapes.

Once, you give your child a brief explanation on 3d shapes, just ask them to draw a few 3d shapes on a white drawing sheet. This helps them to get more involved and concentrated on the topic they are going to do an activity. It is also easy for them to perform the activity by seeing the shapes and doing.

Let us learn how to make a cuboid…

Cuboid:

To make a cuboid shape, first we need to make a rectangular base. Take two equal sizes of sticks as a base and place a ball of play dough on their ends. Now, we are going to connect these two sticks with the help of short length sticks and place them horizontally on the sides of the base (two opposite sides will be shorter).

Now the base is ready. Then place the four sticks on top of the four play dough balls of the base. And then cover the ends of the four vertical sticks with four balls of play dough.

We have come to the end, take exact sizes of sticks same as taken to make the base. Attach them to each other using the play dough balls. That’s it, we can see the shape of the 3d structure i.e a Cuboid.

My little one started clapping seeing the 3d shape which is made of her favorite colored play dough and craft sticks. In fact, she is surprised and saying “Mamma! I can make 3d shapes using play dough apart from tiny toys, insect shapes.”

In the same way, we can make all the 3d shapes using play dough balls and sticks. Now, let us know how to make square based pyramid to better understand the concept of making 3d shapes using simple and interesting materials.

Firstly, make a square base taking four equal sized sticks join them in a square shape using play dough balls at their ends. Now, attach four sticks of equal size vertically on all the four corners of the base. Bring them to the mid-point of the square base slowly i.e. nothing but you are pushing the sticks diagonally to the centre. Join all the four sticks that are brought diagonally to the centre with a small ball of play dough. Hey!! You are done with the square based pyramid shape.

My kids enjoyed a lot doing this activity and they later tried making different shapes. Now they are familiar with moulding the 3d shapes. 🙂

Making 3d Stem Structures using Straw and Thread

Now let us get into our next activity which I already promised you that I am going to discuss on 3d stem structures. That is nothing but making 3d stem structure using again the simple materials that are available in our home.

Materials required

Woollen Thread
Scissors
Straws
Beads (optional)

Procedure to be followed

This is another quick, easy and super fun activity to make large geometric 3d structures. The shapes are made by sucking a thread into the straws and knotting method. Let us see how it is possible to make shapes.

Firstly, make a triangle shape on the flat surface using colourful straws. Now, insert the woollen thread into the straws. (Here to make a triangle shape we need three straws. So, cut the woollen tread into three equal lengths. Cut the thread into enough lengths in order to put knot between the straws).

Now, tie the knots that are inserted inside the straws. Keep in mind that you need to tie the thread of one end of the straw to the other end of the adjacent straw. The same follows to the other corners of the triangle. Finally, when you lift the structure, you can see the triangle shape clearly made of straws holding by threads.

The funniest part happened while doing this activity is my girls couldn’t tie the threads and keep knot as I dint teach them how to do a knot with threads. Hope I should do this before I start this activity. Lol…J so friends make sure that your children are aware of tying knots using thread.

Here you can see different 3d shapes and stem structures which my little girls have tried after I showed the basic structures using sticks and play dough balls.

I highly recommend you to try this activity at home along with your kids. This activity helps your children improve their imagination and creative play and takes their basic knowledge of play dough moulding to next level.

For making different 3D shapes, it’s always super fun to include a variety of materials such as Popsicle sticks, tooth picks, coloured matchsticks and straws. In this way kids can explore different materials as well as discover new things and concepts like which ones are easier for building.

Straws are also perfect to this activity as they are light-weight and easy to mould in our required shapes and easy to cut as well. So, there are no limitations to this activity.

After she finished I explained few geometry concepts and she was able to relate and grasp better now. I referred to the Geomag rods and explained about the triangular and square-shaped pyramid. Also, about prisms and triangular shape. I further incorporated 3D to the lessons.

Keeping the foundation of STEM strong we simplify the science concepts and have made them as small experiments which kids can do on their own with minimal support. The catapult experiments and the balance scales include science concepts and engineering concepts. Likewise, each experiment will contain more than one pillar of the STEM and help students to understand easily.

Happy Browsing and do not forget to give it a try!!

We shall post more for you and you will have the choice to select and make your kid take the challenge.

In our next we want to bring out Coding for Kids! A special new topic for the coding genius in your kid. Watch out for it.

Disclaimer: This post contains affiliate links from Amazon. An affiliate link means that when you purchase using the link provided in this page, I would get a small referral fees WITHOUT any extra cost to you. I highly appreciate your understanding and support.

Catapult STEM Project – DIY Catapult for Kids

August 10, 2019May 3, 2019 by Angela

We are going to add fun to your kid’s life with a catapult experiment. Do not throw the Popsicle stick next time when you buy an ice candy. It will be useful for our STEM project which includes math, engineering, physics, and play as well.

How many of you agree to my point that ‘Exploring physics is bit boring for kids’!? I guess most of them say ‘Yes’. But this time I have come up with a special activity that proves physics and STEM could be so much fun. That is nothing but ‘Making a Catapult at home’.

Catapult!! Have you wondered listening the word ‘Catapult’!? I would say, ‘Yes we can make catapult at home with our kids absolutely’. Building a catapult with our kids would starts out as a craft and ends with an energetic fun activity. The end result could be the wonderful and perfect toy for kids.

What is a Catapult?

A catapult is an ancient weapon or a ballistic device used mainly to launch stones, spears, and projectiles to a greater distance without the help of explosives. It is in use since ancient times and proven to be one of the most effective mechanisms in military during war.

Making a Catapult is a classic building activity and fun science project for kids during summer. This activity doesn’t need you to run behind the fancy stores since it requires only few commonly used household things (kids are familiar with).

Today, we made three different mini catapults in three different methods. I have included a video too along with the post i.e. on the catapult action-how it works after it is made. I know you all are also eagerly waiting to learn. Ok! Let us learn how to make a catapult at home.

Suitable For

No hard and fast rule as to who must try this activity. It is best suited for all the naughty little toddlers, girls and boys from age 3 and above. My little ones are 3+ and 5+ and both had equal fun.

Off course the preschoolers need some guidance and support, to begin with, the projectiles as well as to measure the distance. Instruct them to make a mark with chalk on the floor every time the projectile reaches to know the longest distance the catapult travels. Explain to them why the distance varies every time even though it is the same catapult and same kid does it.

However, 5+ years kids will be eager to measure the distance on their own. You can even teach them to make a table and draw a graph with many readings. Don’t spoon-feed them but ask them to find a way to measure the distance. You will be surprised to see the brainpower of your kids.

On the other hand, ask 7+ kids to design a catapult on their own. They will start from scratch. Let them find out by making the arms short and long to see how they work and the projectile distance. They will understand the force and the foolproof length of the arm etc by doing on their own.

Method 1 : Making a Catapult at home using Popsicle sticks

Items needed to build a catapult

Building a mini catapult with Popsicle sticks require very few items or supplies. Let us see.

Popsicle sticks
Rubber bands (choose different colours)
A bottle cap from a milk jar or gallon jar
Hot glue gun
Tiny objects like cotton balls to launch
Straw (prefer big one)
Wood
Spring

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Procedure

Step-1: Create the base of the catapult

Stack two Popsicle sticks and glue it together in order to make it standard. Make a square shaped base using these stacked popsicles. Use rubber bands to make ‘U’ shape and tie them near corners to create a square shaped base. On the fourth side, use a cylindrical shaped thin wooden stick and tie it to the corners of the ‘U’ shaped base so that it is making a square shaped base all together. Do not forget to pass a 2 inch straw piece in the middle of the wooden stick.

Step-2: Create a t-shape

As the title suggests, create a ‘T’ shape at the fourth side where we have attached a piece of straw. This time you need to use glue to fix it to the Popsicle stick since it need to be strong to hold little weight.

make square structure with sticks catapult design

create rotating shaft for catapult

catapult base with sticks and rotating shaft

Step-3: Attach Bottle cap

Now, it’s time to arrange some space for the projectiles (nothing but our tiny objects like marsh mallows or cotton balls or any light weighted plastic balls) to launch. Attach a bottle cap upside down to the free end of the ‘T’ shaped Popsicle (on top side). The bottle cap is used to launch tiny objects as projectiles for our activity. 🙂

catapult design with spring and ice sticks

Step-4: Attach a spring

A spring of about an inch should be attached to the Popsicle stick which is quiet opposite side of the wooden stick where the straw is inserted. Glue it to the Popsicle so that it does not move or shake during experiment. After attaching the spring make sure the spring is quiet in the middle of the Popsicle and quiet down to the bottle cap end as shown in the figure.

attach spring to catapult base

Here we go, our powerful mini catapult is ready to launch projectiles for our simple and engineering project for our little ones. My kids had a blast after preparing this in front of their eyes. All it needs is a little patience and time for your kids to show them such a beautiful and educational act.

catapult with spring ice sticks in action

Method 2 : Using the Same Base

Now we are going to learn second method using the same base. This time my elder daughter created the base in my direction. I am happy kids showing interest towards STEM activities. J

Step-1 Create a base

Create a square shaped base using Popsicle sticks, rubber bands, wooden stick, a piece of straw and glue. You can go through the step 1 of first method and follow the same.

Step-2: Attach Vertical Supporting Structures

Do not get confused!! Look at the picture and you will get an idea. Just attach to Popsicle sticks vertically to end of the base means you are attaching two Popsicle sticks each at one side. No need to add on all sides. Just attach to the adjacent sides of the wooden stick.

build big catapult structure

As shown in the figure bring the two free ends of the vertically placed Popsicle sticks to the middle point and tie them with a rubber band. Repeat the same to the other opposite side also. Now the Popsicle sticks give triangle shape (when we look from the sides) and looks like supporting or side walls to the base.

Step-3: Place a Popsicle stick on the top

Now as we called it as supporting walls, place a Popsicle stick horizontally attaching both the vertical shaped structures on the sides. Always see the figures we uploaded not to get mislead. Take the support of the ‘V’ shaped groove formed while making the vertical shaped assemblies. Now the whole structure gives the shape of a swing (outline shape) which we see in the kids play area.

Step-4 Attach the basket to launch projectiles

Arrange the basket for our tiny projectiles to launch again using Popsicle stick. At one free end attach a piece of straw in order to extend the length according to our catapult skeleton. (If it is not required for you then you can directly attach the bottle cap to the Popsicle stick. This is an optional step).

attach rubber band for rotating motion

Step-5: Glue the basket to the Catapult skeleton

Now attach the already made basket arrangement (shooting arm) to the straw using a glue. Glue fixes the shooting arm strongly so that it could bear enough tension. Use rubber bands and twist along the shooting arm and the horizontal Popsicle stick to give enough tension to the shooting arm.

catapult full model design

Load some small and light weighed objects to the ammunition basket and that’s it. Your mini catapult is ready to fire.

catapult in action

Method 3 : Plastic Spoons and Popsicle sticks

Supplies required

Popsicle sticks
Rubber Bands
Spring
Plastic spoons
Bottle cap
Glue

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Step-1: Create a base

As we do in above two methods, the first step is to create base but this time it is different base. Let us see what it is!

You can follow the step by step instructions given in the Instructables as I did as they are clear and visual.

Take 5 Popsicle sticks and stack them together on top of each other. Be sure to stack them neatly. You can use the tighter rubber band to secure them tightly and not to move.

catapult stem activity - fb

Step-2: Create an arm

Take another two Popsicle sticks and stack them on top of each other (as we did in the first step). Secure them at one end with the help of rubber band. So simple!! You are done with creating arm. Are you thinking how!? Don’t scratch your head. J Here the simple trick is just bend the other free end towards you (means outwards) thus creating an arm.

making and testing catapults

Step-3: Attach the base to the arm

Take the arm base and pull one of the free end of the stacked Popsicle base towards you resulting in a ‘V’ shape format. Now place the main base (made of 5 stacked Popsicles) in between the ‘V’ shape of the arm. Make sure you place the main base one half inch away from the end that is tied with rubber band.

Wrap a rubber band around the arm and the base in order to secure the arm to the base.

Step-4: Glue the Bottle Cap

Now create a basket for the ammunition to launch. Glue a bottle cap to the free end of the arm of the mini catapult that serves as a basket for projectiles (marsh mallows, ping poms, cotton balls) to launch.

Your catapult is ready to launch your tiny projectiles. J As I said it is very easy to assemble catapult using Popsicle sticks and rubber bands. Am I right!? Hope you all agree. J You can try using simple plastic spoons attaching to the free end of the Popsicle stick and make use it as an ammunition basket. Use rubber bands to fix the spoons to the Popsicle stick.

Catapult science, engineering and maths (STEM) activity for kids

Measuring distance - Catapult STEM activity for kids, that combines science, engineering and maths with play

Observations

Don’t panic to look at this picture, trust me it is easy once you get a hold of the design. Kids can do it themselves. So have the patience for the first time.

1) Try changing the different angles of the rubber bands

2) Add additional tighter rubber bands and observe whether it is making any difference in catapult’s power.

3) Launch different objects in the ammunition basket like ping pong balls, pom poms, and marsh mallows etc. and observe which one is going farthest!

Test #1: Which is powerful and travels a long distance

My younger one Tisha was so excited to do it. With a line marked on the floor as the beginning line, we began with our experiment. Every time she used the catapult and started making lines on the floor to measure the distance. She did a great job using a tape. With my help, she also noted the readings down.

My elder one Pritika did it herself and measured too. Both of them tried thrice on all catapults and compared the measurements.

Test#2: Now to measure the height

We now started talking about measuring the height as we thoroughly understood and equally had fun with the length. Here we even shared views about the design and the trajectory.

Now we did it with a Magna Tile tower to monitor the square in which the projectile hits and that was easy to measure the height as well.

It all began with a 6 square high tower. Yes, we did it and the projectile reached the top. Again we made some changes to the tower height and adjusted the start line position as well.

We tried a couple of times to conclude on some details by using all the 3 catapults. Finally, we understood that we require a tall tower.

Fun Science Facts behind Catapult

Using a catapult now launching a projectile is quick and easy and there are no explosives required.

The science behind it explains kids to learn how the energy is created, stored, transferred and converted. Basically, a catapult works on energy transfer from one object to another object. We are talking about the energy much but where is this energy stored!? The energy is added and stored in the Popsicle stick when the tiny projectiles are added to the basket (bottle cap).

When you let go the Popsicle stick, the stored energy is transferred to the object launched in the bottle cap which then flies through the air. Catapult also uses the elastic energy which is transformed into the kinetic energy under tension stored in the rubber bands. Here we need to remember one physics formula we studied in our school. I.e. the amount of force is directly related to the amount of the mass. If the mass of the projectile is increased, then it requires more force to convert the stored energy into kinetic energy. The extra force is created by using more elastic bands. The transferred kinetic energy is the main reason for throwing the projectile out of the bottle cap.

These devices are in use for several years as well they come in any size and shape. There are simple slingshot types and complicated trebuchet types are available. These are large one which will let launching of large boulders and knocking down even a castle wall is easy.

The path taken by the projectile is called the trajectory. The material flies in the air and the force applied to the catapult influences this distance. The release angle, projectile weight, resistance of air as well as gravity can be learned in this experiment.

You can make your own catapult and it is the best STEM activities which you should not miss ever. Loads of fun and science in it.

We did not stop just with making the experiment but explained about the need for STEM to little girls. We always want to make out little princess a scientist.

Now, coming to the catapult, we already made an upcycled catapult and enjoyed deeply. This time we are making a catapult with a twist and used ice candy sticks. Do you know what, I have a fascination for this since my childhood? Made this dream come true with my two angles.

It’s time to try yourself to find the catapult projectile distance, trajectory height, and consistency as well. You can try with different objects and apply different force to test in a different manner.

Check out for more ideas on our Fun Activities in Physics Page.

Try this upcycled catapult without buying anything from outside.
Refraction and light experiment requires nothing but water in a glass, paper, and pen.
Balance scale can be done to compare weights.
Magna Tiles experiment is also a great way to explore geometrical shapes and much more.

We would love to have you following us in Pinterest on the titles Go Science Girls.

It is also good if you can subscribe our newsletters to get updates on our activities. Yes, we will send mail to you and help you teaching science to your kids in a fun way.

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Some Questions for Discussion

What is the science behind rubber band catapult?
The catapult science basically involves some physics and engineering skills to hurl a projectile without the use of an explosive. It works mainly by using potential and kinetic energy stored in the rubber bands. Potential energy is the store energy where as the kinetic energy is the energy in motion. Also, the three primary energy storage mechanisms that help the catapult to work are torsion, tension and gravity. A catapult store energy every time you stretch the rubber band and until you hit the trigger. When you let go off this rubber band, the potential energy is released creating a force. The force of this energy is responsible for the flung of any object (upwards or forwards) attached to the rubber band.
How does a catapult get its energy?
A catapult gets energy either from the twisted ropes or the rubber bands. When you stretch a rubber band the potential energy stored is converted into kinetic energy. These are the two main energies used for the catapult’s action.
How high can a catapult shoot?

In medieval period, the largest trebuchets (with throwing arms 50 feet in length and ~20,000 lbs counterweight) could throw stones 200-300 lbs to a distance of about 1000 feet. While the modern torsion catapults can fire 400 m to 500 m and any that can’t shoot 300 m [ i.e.. bow range] are useless. To achieve maximum accuracy and effect rocks must be spherical.
Who invented catapult?
Catapults were invented by the ancient Greeks. The Greek Dionysius (the Elder of Syracuse), who was looking to develop a new type of weapon, invented the catapult about 400 BCE. Thereafter, it became a key weapon in warfare and remained so up through medieval times. In ancient India, they were used by the Magadhan Emperor Ajatshatru around (the early to mid) 5th century BC.
How does a catapult relate to physics?
A catapult actually works on the three main terms of physics i.e. tension, torsion and gravity. Also it works on energy storage mechanisms (nothing but the stored potential energy and energy in motion kinetic energy) says that a catapult works on physics. Newton’s second law relates an acceleration, object’s mass, and force with which it is moving. We can also observe this law when the projectile hits the ground. All these moments reminds us physics.
What are the 3 type sof catapults?
The three main types of catapults are:
1) Ballista: The ballista is a missile weapon, very similar to a cross bow that launches a large projectile at a distant target.
2) Mangonel: The mangonel is the most iconic catapult which comes the first in our mind when we think of catapults. It is basically made of wooden arms and a bucket to launch projectiles.
3) Trebuchet: The trebuchet is bit different in model when compared to the above two catapults. It is made with a long arm (balanced on a fulcrum) and short arm (to counter balance). The Trebuchet was designed for max power and distance.
What kind of energy is used in a catapult?
When you use your catapult to launch a cube you are transforming Potential into Kinetic Energy. Potential Energy is the stored energy and the kinetic energy is the energy of motion. When you twist the rubber band, tension is created and stored in the twisted band. When you let go the rubber band the released kinetic energy helps to throw off the launched projectile.
What came first the catapult or trebuchet?
Catapults are invented first during ancient times. Though they are good at accuracy, trebuchets are invented by chinese to attain greater range of accuracy and maximum force and power. The main difference between both are trebuchet uses a swinging arm to throw a projectile. Without such a sling (swinging arm), the machine would be a catapult.
Why is a trebuchet better than a catapult?
Trebuchet are most powerful catapults, specially designed for maximum force and power. Trebuchets are believed to be invented by the chinese in 300 BC. The trebuchet was preferred over a catapult due to its greater accuracy and greater range capability. A trebuchet works by using the energy of a falling (and hinged) counterweight to launch a projectile, using mechanical advantage to achieve a high launch speed.

Upcycled Catapult – STEM go green DIY Challenge

September 21, 2019April 30, 2019 by Angela

You can now make an upcycled catapult easily. With the right projectile ready you can now teach Fun physics for kids.

Easy DIY Upcycled Catapult - science play for kids

We are going to be part of the 4 weeks STEM challenge. It is running for 28 days with hands-n science activities. Every week they will announce a new theme and under the Go Green theme, we are going to make a DIY. GO green is nothing but an eco-friendly experiment with some science concepts involved in it. Your kids can have fun and you can feel glad to teach them science. We will be using upcycled items which are available at home. Also, it is part of 10 minutes activity and you need not spend much time.

Suitable For

It is an experiment with logic and fun so you can try with all age group kids. How will different age group find it useful is listed below.

Toddlers – Can have fun with the activity but make sure you are using a soft projectile

Preschoolers – These kids can try changing different projectiles and understand which one goes high and far.

Kindergarteners – They will do the catapult on their own and can try with different items to find the best make. Try using projectiles of different size and shape to understand the science behind the experiment. Also, will try to move the fulcrum or use a long beam and find the effects. You can fix targets to hit and score them to announce the winner.

Things required to make the DIY catapult

- Cardboard tube which is strong (preferably an empty toilet tissue roll)
- Hair elastic
- Projectile
- safety glass (optional)
- Wooden spoon

Making a DIY catapult using recycled materials

Check the tube that is available at home. The one I used is the toilet tissue roll which will be thrown after use. If not use a rolling pin and that will do the job.

Loop the elastic on the cardboard tube two times. In the place where the elastic gets crossed insert a wooden spoon and fix it. So at the end of the spoon you can keep the projectile.

With this basic catapult model you can start your experiment and choose the projectile. For toddlers use a crushed paper and that will be soft. Also, can be played indoor without any fear of damage. Indeed it is one of the best rainy day activity.

Where did it go Experimenting with projectiles
Indoor science fun with DIY catapult and projectiles

Try this activity outdoor when playing with preschool kid. Try with pinecones or seed pods as the projectile.

With these projectiles, you need not worry about any damage caused to the neighbor’s house.

Also, we suggest you to use the safety glass and protect kids eyes. You can check this to know about safety glass.

Upcycled eco-friendly catapult - science fun for kids

I have tried this several times as my kids love to do this at home and outside. It’s really a fun activity. You can also try this and have fun.

DIY Upcycled lever catapult - fun science activity for stem goes green

Fun Science

This is a lever and the science behind this is similar to a simple machine. It consists of a beam, the spoon handle is the beam. It is fixed to the fulcrum (cardboard tube) at one point with the help of the elastic. Imagine a seesaw that works on the same principle.

The lever will affect the effort required to raise something. Vary the distance between the fulcrum, force, and the load (projectile) to test the height traveled by the projectile.

This experiment is listed under 4 weeks of STEM challenge. Take a look and you can find many activities for kids.

Easy DIY Upcycled Catapult - fun science activity you can do at home, indoors or outside. Great STEM activity for kids

How To Make Balance Scales for Toddlers and Preschoolers

August 19, 2019April 30, 2019 by Angela

Toddlers and preschoolers always love to weigh every item. They play “Which one is heavier?” game and we can now help them make a balance scale at home. Side by side you can also teach them about gravity.

My elder daughter is 7 years old now and she started learning about measurement and weights in Maths. So I had to make a homemade balance scale. Firstly, I thought it would be very difficult to make a balance scale but once I started working on it I realized that it is much easier than I thought.

Our balance scale is a simple balance, a rod with a pan at each end that is suspended in the middle. This is a perfect activity for introducing the kids to the concepts of weight and measurement. So let us add little balance to our day-to day life.

Suitable For

Children who are 5 years and older are perfect to do this experiment. However, both toddlers and preschoolers can also try this. Tisha had real fun and she is 3.5 years old when we did the simpler version of this experiment (scroll down to the second part)!

What Your Child Will Learn or Practice

How to compare and contrast objects
Estimation skills
Measurement skills
Force of gravity

Materials required

Two identical paper plates
Scissors
Measuring tape
Pencils to mark
Thread
A long and big straw
Jump clips
Paper clips
A long stick (should be of same length like straw)

Building a Balancing Scale

Balance scales are often used to find weight. Balance scales work like a seesaw. They have two main parts: the beam and the fulcrum.

1) Making Baskets for the scale: To make a homemade balance scale at home, we require two identical paper plates. Punch three holes to each plate using a hole punch. Make sure to make the holes close to the rim of the paper plates and in a triangular shape. If you don’t have paper plates, you can make use of plastic or paper cups to serve the purpose.

2) Making the strings: Take six pieces of woollen thread that are each around two feet long and cut. You can use any kind of strings which perfectly balances the balance scale. Thick and strong strings make the balance scale more durable. After you cut the strings, please check whether all the strings are of same length or not. If not adjust them by cutting using scissors.

3) Attaching the strings to the plates: Insert the three strings to one of the paper plate separately in to the three holes made. Repeat the same to the other paper plate as well. Then bring the free ends of the strings together to the centre point and give a knot. Insert a paper pin around the knot as if to hold the paper plate perfectly. You can follow our pictures to get an idea on how to insert and tie up the strings.

4) Making a beam: Beam holds the objects to be weighed in the weighing baskets. In order to make beam, measure the length of the long straw and cut according to our required length. It depends on how big we are going to make the balance scale.

5) Attach the weighing baskets to the beam: Now beam is ready in your hands. Insert two jump clips one each at the free end of the straw as shown in the figure. These jump clips help to hold the weighing baskets freely on both sides of the beam. Now the model looks like a see-saw. J Take a piece of woollen string and tie it to the beam exactly in the middle. This helps to hold the beam to the fulcrum.

My younger kid Tisha started shouting and clapping seeing the see saw like model thinking that I am going to make one of her play area rides. J Sometimes kids are too innocent to understand the things that are happening around. No matter what she understands but younger kids enjoy watching this activity.

6) Making fulcrum: Fulcrum is also one of the major parts of a simple balance. It helps to hold the beam up and move. Take the wooden stick and a pencil and tie up both together. Now bring the stick and pencil perpendicular to each other. See the figures for reference. Now attach beam and the fulcrum with the help of the small woollen string (in the middle of the beam). But where!? The answer is you can attach to one free end of the pencil. Almost we are nearing to end the activity.

7) Wrapping up: Now that your balance scale is almost ready. I made a thick and hard base using hard thermocol sheet. Tisha was excited to paint thermocol and she used black color to paint. We made a hole exactly in the centre of the thermocol base so that we can insert our simple balance scale in the hole.

Now we are ready with the homemade balance scale to measure and weigh the objects. It is easy to weigh any objects using balance scale. Place the objects that you wish to weigh on one side of the weighing balance machine. Add standard weights to the other pan. Check the weight of the objects being placed according to the standard weights.

Here is our little homemade balance scale. My elder daughter proudly displayed it to all her friends in our society and explained how the balance scale works to measure weights. My kids enjoyed weighing the small objects like paper pins, dice etc…Every day they are using balance scale measuring whatever the objects they find in the home. 🙂 As a parent I am very happy to see kids learning some simple craft science experiments even at home. I highly recommend you to try out this simple experiment along with your kids and do amaze everyone around you with your discoveries and research.

Building a Simple Balance Scale Using Coat Hanger

I wanted to make a simpler version of the balance scale to teach my younger one. Here is another version of balance scale that you can try at home.

Which one is heavier fun science for toddlers

This 10 minutes craft is fun and can be made by kids very easily. Tisha my 2.11-year-old little one enjoyed making this and went crazy at the end of the day. It was so exciting and she was looking for objects at home to weigh them. Did not spare any single toy from weighing.

She compared weights of the following things.

Tangerine
Christmas baubles
Costume jewels
Lego Duplo animals
Mandarins
Decorative pebbles

She will collect things in the bucket and run to the balance scale and weight them. We composed a song in a rhythm and shouted “Which is heavier?” while comparing the buckets and she will point to the bucket that is heavier correctly. I will ask her how. Then she will explain to me that the bucket with more weight will go down when compared to the other.

I was happy for my Tisha as for her age she understood gravity very clearly.

Things required to make DIY Balance Scales

paper cups – 2
children’s clothes hanger and notches
kitchen twine
scissors
single hole punch

Links (*Affiliate) are added so that you can purchase things in case they are not available at home. However, I had all at home.

How to make a DIY balance scale using coat hanger

Take one coat hanger and hang it in a place where it can swing. But make sure it is not tied at a height. Let it be accessible to kids. I did it on my pantry door.
Using a hole punch create holes in the paper cup to tie twines of equal length and make it look like a bucket.

Let it be lengthier so that kids can handle them easily. Also, they can remove and hang them on their own.

3. Instruct kids to fill the bucket with things.

Let them feel free to do it and anything can be filled. As long as it is solid in nature to avoid any mess. Let the kids guess which will be heavier before they see the results.

4. Now by adding the buckets with the hanger, your kids can witness the heaviest bucket by noticing that heavier one moves down.

If they have guessed it correctly, then ask them how? Also, teach them about gravity. Allow them to change things and understand better about weight and balancing.

Slowly they will get a hold. Show them about balancing with equal weights in both buckets as well.

Do not keep on tracking them but let them explore and ask them to make a note of their observation. But let them guess every time to make sure they understand the weights correctly.

Tisha was explaining her dad with so much excitement and demonstrated everything to her.

This kept them busy in their “Which one is heavier?” game for couple of hours 🙂

Fun Science Fact

Gravity is nothing but a force which pulls things downwards. The earth core in the center attracts things towards itself and heavier things move lower than the others. Therefore gravity pulls the object downwards.

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DIY Fridge Door Marble Run Using Magnets

September 1, 2019March 3, 2019 by Angela

This is a fun STEM (STEAM) activity of making a marble run with magnets for kids. This is best suited for refrigerator doors any steel surface (you can also try with magnetic white/black boards.)

Suitable For

This can be done by all age group kids namely, preschoolers, kindergarteners, and school-aged kids. My kids Pritika and Tisha were 6 and 4 years old at the time we tried this activity.

I would like to share this with you all and you can also have fun with your kids. Follow these steps and let your kids make one for your fridge door as well.

Kids can make it on their own and it is very easy too.

Steps to follow for making the marble run for the fridge door

Things required

Cardboard rolls – We used toilet rolls and paper towel rolls. You can also include foil rolls or cling film rolls. Multiple sizes of rolls can be used.
Tiny balls like pom or marbles
Scissors
Magnets
Glue
Decorative Tape

Fridge door marble run

In case you don’t have rolls as I mentioned before, then you can make it from cardboard but let them be decorated with tapes to look great on the refrigerator door.

Using glue gun we managed to stick magnets on the side of the rolls. However, usual craft glue (PVA) can do this job perfectly. But leave it overnight and allow it to dry completely.

Choose magnets that are strong only then steel balls or marbles can be placed in the rolls. It can withstand the weight. However, pom poms are not very bulky and you can choose light magnets in that case.

Decorate toilet paper rolls with washi tape stick on magnets to create a magnetic marble run for the fridge door

My kids both elder and younger decorated the cardboard rolls. Off course I helped them with the final finishing.

Testing out the marble run

Also, we made them look in different shapes by cutting the corners into small sections, etc. You can skip this if kids are trying and don’t allow them to handle scissors alone.

Creating magnetic marble run pieces

Now after completing, place them on the fridge. Kids will love to play with them.

Magnetic marble run for your fridge door fun science for kids

Make a magnetic marble run

Make a colourful DIY magnetic marble run

DIY magnetic marble run

Points worth considering

How many can be added in one go (zigzags)?
Using a stopwatch can we time the running marble? Is it possible to make it slow or quick by modifying the track?
Try to run marble with heavy balls, light balls, rough, and smooth balls. Test if the design can handle all types of balls or should the design be modified? What is the relation between the ball type and speed?

Fun Science Fact

Factors influencing the marble run design are as follows.

Gravity – It is the force which will pull the object in the downward direction (in the direction of the earth’s center). Thus marble travels down.
Energy– The speed of the travel will decide the energy consumption. Faster it travels better energy it will possess. The object collides and exchange energy between them thus changing the motion.
Force– Heavy object will have more force and rapidly moving object will have more force too. At the same time, heavy balls require a slower track to handle the force and preventing from falling out of the track.
Friction – The resistance happening when two things rub against each other is called friction. The ball texture affects friction.

Make a DIY magnetic marble run for the fridge

In this activity, you can teach them science as well as introduce STEM activities in a playful manner. Also, include art in the STEM activity to make it STEAM activity.

Science–Marble runs make a physics activity with concepts like force, gravity, friction, and energy
Technology– Using a stopwatch to set time is the technical aspect.
Engineering– Designing and testing with different marbles, weights, texture, and size teach engineering activities.
Math– You can estimate, measure and compare time and teach math for kids. Ask kids to make a table by estimating, measuring and comparing the distance traveled by the marble. You could record results in a table.

+ Art – Tube decoration with paints and tapes is the best part of art activity in this experiment.

Make a DIY magnetic marble run for your fridge door

Check Physics Experiments for Kids archive for other experiments.

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