A stronger wooden rubber band car

After making several different 'cars' a couple of weeks ago, our daughter had one final try at making a stronger faster rubber band car before she goes back to school next week.

She decided to stay with the simple design she'd used before 
(you can see her previous creations and how well they worked here).

New Materials

This time she used a thin piece of plywood for the base instead of cardboard. The reason she did this was because she wanted to add more rubber band 'engines' to her car after a discussion and suggestion from Granddad! She had tried adding more rubber bands to her previous cardboard car, but the card just bent with the force of the wound up rubber bands!

So - wooden it was - and we found some wooden dowel rods to make the axles stronger too. We used cut up sections from an old board marker pen casing to slot the dowel rods through so they would run smoothly.

Here is her completed final rubber band, wood and CD car. If you can see on the back axle there are three small screws to attach the rubber bands to and notches on the front of the car to loop the other ends around. So this is her '3 cylinder' car! More engines, more power!

Test run

Here is how far it managed to travel, carrying a tuna can, up a slope we had built from cardboard.

Although the car didn't make it quite to the top of the slope as we'd hoped, we'd spent enough time on the cars and so decided to stop there and take stock of what we've learned.  Maybe we'll revisit making cars after a few weeks break!

What we learned
So what did we learn (and I say we because I've never made cars before and learned just as much as our daughter did!)?

• We learned how to make a rubber band car and how it works with potential and then kinetic energy. 

• We learned how different sized wheels affect the movement of the car.

• We learned about friction - adding sections cut from rubber gloves to the CD wheels to allow them to grip the tiles.

• We saw the difference when putting the car on different surfaces, and with different weights on the car. 

• We also learned about the strength needed in the construction materials and tested various different types. 

• We had to use lots of creativity to make these cars - choosing materials and learning how best to cut, shape and attach them together.

• We made lots of mistakes and persisted with trial and error, making the successes and achievements so much more exciting and satisfying!

Give it a go yourself!
I would highly recommend spending time with your kids learning how to make something like a rubber band car.  I watched several you tube videos myself first to get the basic idea of what to do, so that I could help as best I could.  We also did things in small stages so that neither of us got too fed up or frustrated.  Building up the project over 3 weeks was also definitely a good thing to do, as it gave us time to process each step and everything we had learned before trying to apply and build upon that when we tried again.   We used materials we found in the house so it didn't cost us anything other than a little time, but it was time well spent, learning and experiencing something new with my daughter - and not only that, it was great fun!

Inspired by
This project was inspired, partly by a balloon car kit our daughter got for Christmas, and partly by the Opti-minds challenge our daughter took part in last year. She and her friends did the Language Literature Challenge last year but are considering doing the Science Engineering Challenge this year and so I thought it would be fun to have a go at last year's Science Engineering Challenge together in these summer holidays to give her an idea of what to expect. They had to move a tuna can at least 1.5 metres in distance and upwards at least 0.5 metres.  Although we didn't quite manage this, I think our daughter learned enough in terms of science principles and also the need for persistence and trial and error, so that if her team chooses the Science and Engineering challenge this year, they will have at least some ideas on where to start!
Have your kids ever done a challenge like this before? I think Opti-minds, or other challenges like this are a great thing for kids to do to learn all kinds of skills. I will be interested to see which challenge our daughter's team chooses this year.

 

Making more cars - propeller and rubber bands

After our younger daughter's success last week making her own Balloon Car Racer, we decided to try making some more different cars powered by other means.

The first we tried was a plastic bottle propeller car, made following this video. Our daughter made it herself, figuring out the best way to punch holes and cut the various materials.

Here it is all finished - looking good!

Unfortunately when we wound up the propeller, the car didn't race forward as we'd hoped!

We asked for help on Facebook, and were given plenty of suggestions like adding weight, cutting more holes and rubber bands on the wheels.  We tried a lot of the suggestions and persisted for a long time until the rubber bands snapped and we put it aside for the day, frustrated!

A couple of days later, we decided to try again with another rubber band powered car. 
We found a great YouTube channel called 'GrandadIsAnOldMan' and watched several of his videos for inspiration and ideas.

First - and now I'm going to stop writing 'we' as our daughter well and truly made these ones by herself!
She made a cereal box car with rubber bands that wound around the back axle to power it. The wheels were milk bottle tops and the axles were kebab sticks.  This car worked but only ran slowly and couldn't carry any weight inside it.





Next she tried with larger mayonnaise jar lids for wheels - and rubber bands around them to gain traction on the tiled floor. This worked much better! The car was faster, but unfortunately still couldn't carry any weight!




Finally, she tried a flat bed car just made with cardboard, drinking straws to push the kebab stick axles through and CDs for wheels.  This worked REALLY well and was strong enough to carry a small tuna can!  Success!!





The cars our daughter made over the past week have provided lots of fun, entertainment and learning experiences.  Seeing and sharing the joy of success when she has made something that works as expected is amazing. 
She has learned some physics principles, for example kinetic and stored energy, friction and traction. 
She's learned persistence and perseverance to not give in when things didn't work - instead to look at why they aren't working and how can she improve it.
She has also learnt to make things for herself from materials we had on hand in the house - enjoying this and gaining far more satisfaction than from the initial plastic car kit she started with a week ago.


But the challenge isn't complete. There is a motive for making this car and transporting a tuna can. The next step being to make it go up a slope! For that we'll be revisiting the propeller car to see if we can add more force to power the car.

I will post on the progress of this project again in a few days!

Have you ever made a small DIY car like any of these?

Balloon Car Racer - a kit and a DIY!

A few days ago, our elder daughter made a solar helicopter from a kit she received for Christmas. Yesterday was our younger daughter's turn to try her Christmas kit - a Balloon Car Racer.

It was fairly simple to construct using the instruction booklet - just a few plastic pieces to fit together, and the balloon on top.

Pump up the balloon with the pump provided and let it go!

It worked really well, as you can see on this short video clip.

Since this car was such a simple concept, my daughter decided to see if she could make one herself.

She used the box that the kit came in for the body of the car. For the axles and wheels she tried wooden kebab sticks and buttons first of all.

The car did move, but as the holes in the buttons aren't in the centre of each button, the car kind of bounced up and down and the force of the air from the balloon wasn't strong enough to move the car in this bouncing motion.

The balloon was attached to the end of an old ballpoint pen casing, taped to the box with duct tape.

Cardboard circle wheels were tried next, but worked no better - then we thought of plastic lids.  They were easy to punch holes in the centre to push the kebab sticks through and were much sturdier than the previous 'wheels'.
Finally, the new DIY balloon racer worked!




The excitement we both felt when the car actually moved after blowing up the balloon was brilliant! Such a sense of satisfaction having constructed the car from scratch - and far better than simply constructing a pre-prepared kit!

My daughter then tried putting things in the box car to see what it could hold, but it's not strong enough to move when carrying anything of noticeable weight.

This has piqued an interest in my daughter though - and next we're going to try a different way to propel her newly built car and how to make it stronger.

Have you ever made your own model car? 
Do you have any tips or suggestions for us?

Building a Solar Helicopter

For Christmas our eldest daughter got a kit to make a solar powered helicopter. Today she constructed it.

It was fairly straightforward to construct with clear diagrams for putting the pieces together - reminding me lots of lego instructions and how great it is for kids to learn to follow these kinds of instructions with the 3D diagrams, rotating them the right way around to fit each piece correctly -  a valuable skill they may use when they grow up and buy flat packed furniture!

The helicopter didn't take long to construct and once in the sun, the blades spun perfectly!

This, together with the solar bugs

 and solar lights we have in the garden,

 led us to question how solar power actually works. With a little help from Google we found a great explanation here.

In short - solar cells have two layers of silicone, one treated to remove some electrons, the other treated to add electrons. As the sun hits the layers, the electrons move from the crowded layer to the one with more space, then bumping into other electrons and causing them to move and flow, so creating an electric current!  So simple.

Silicone is special in this way as most materials just heat when the sun hits them (the electrons vibrate) but in silicone the electrons actually move when the sun hits them which is why it is used in solar panels.

For such a simple and straightforward clean energy source, it is crazy that we aren't using it more. Especially considering these trivia facts that we found (source):

The Earth receives more energy from the sun in an hour than is used in the entire world in one year

It would take less than 1% of the Earth's land area covered in solar panels to supply all of the world's electricity needs.

For a simple kit, it created a lot of interest and discussion about solar power, which we will definitely be exploring more!  It also led to interest in plants using solar power too - in the form of photosynthesis, which I'm sure will lead to more experiments and learning too!

In 2016, we are aiming to 'try something new' every week. This is our new thing for week 1 of the year.

Will you join us and try something new each week? It could be a food you've never tried, a game you've never played or perhaps a place you've never visited. Each week we'll share here what new thing we try.

We'd love to hear what new thing you've tried this week - leave us a comment here or on our Facebook page.

Purple Cabbage pH Science Experiment

I've read about this experiment in several places and really wanted to try it with my girls. A few days ago, we finally did it and had lots of fun!

What is the Purple Cabbage Experiment?

The basic idea is that purple cabbage juice can be used as a pH indicator. The girls are aware of the pH scale from their weekly testing of the fish tank water, so at least that made the concept easy for them to understand. It's always good to have something in their day to day life to relate things to - it makes things more easily understandable.

How to make purple cabbage pH indicator

The experiment involved first of all extracting the juice from the cabbage.  We found 3 different recommendations on how to do this

1. Put cabbage leaves in cold water, bring to the boil and boil for 10 minutes then strain off the juice.

2. Chop cabbage, pour over boiling water and leave to soak for 10 minutes, then strain off the juice.

3. Put chopped cabbage and water into a blender and whizz up!  Then strain off the juice.

We decided on what I thought was the simplest method - number 2.

We checked a colour chart we found online as to what colour the purple juice should turn to indicate acid or alkali:

(source)

Then we collected some medicine cups and a dropper and chose what substances to test the pH of.

What did we test?

First we tested our own saliva, which should be a healthy alkali.

Both my daughters ones were alkali, mine was neutral. From what I found when researching this online - that would be about right. Kids saliva tends to be more alkaline and adults neutral to acidic.

So success for our first test!

We then went on to test several other things:

Here's the colours after adding the purple cabbage juice indicator..

And some more..

Once again - after adding the purple cabbage juice:

The girls were learning that citrus fruits - like lemon and orange are acidic, and bicarb of soda was a good example of an alkali.

And finally:

It was good to include the fish tank water in there - and for it to come out as a neutral, just as it had when the girls had tested it with the bought pH test kit earlier that day! Demonstrating again that our experiment did work!

This was a fun and simple experiment to do with the girls.

I think the colours you get do depend somewhat on the concentration of your cabbage juice. 

You could spend a little more time to do a more accurate experiment perhaps with older kids - making your own colour scale, and recording the results in a table.

However for my girls - aged 8 and 10, this was just a quick, fun experiment to do in the holidays.

Have you ever tried this?

Do you have any other simple and fun science experiments to recommend?

Growing crystals....or not!

A while ago I decided to try an experiment with the girls to grow Rock Candy or Crystals.  I found several sets of instructions online and we went ahead and made our sugar solution, added colour, cooled it and put it in a jar with a pipe cleaner suspended in it for the sugar crystals to grow on.

Unfortunately it didn't work! We had some tiny crystals form but nothing like those in the pictures with the instructions.

Then for Christmas, our eldest daughter got a boxed kit to grow crystals with.

She carefully followed the instructions and then patiently waited for the crystals to grow.

Unfortunately again the experiment did not produce great results:

I've since read that in humid conditions crystals won't grow as well because the liquid remains warm and won't give up the dissolved sugar (or other part) which would normally form the crystals!

Living in the tropics - it is very humid - and likely to stay this way for some time.  Perhaps we'll have to come back to this experiment again in winter (July / August) when the humidity levels are much lower!

Still - the point of science experiments is to find out what happens - and we've learnt something from this result!

Often the best experiments are those that don't produce the results you expect - there is more to learn from that as you begin to consider why!!

  Hopefully later in the year we'll have more success growing some bigger crystals!

Have you ever grown your own crystals?

A Science Experiment - Melting Ice

Last week I found this great book in a second hand book shop. It has heaps of fun ideas for activities to do with kids at home with easy to find materials.

Today I picked a random experiment from the book for the girls to try - a nice simple one called 'Melting Ice'

The experiments are printed out very clearly with an aim, materials and steps for each one. The book is also divided into six different sections on Astronomy, Chemistry, Geology and Geography, Weather, Biology and Physics.  The experiment we chose today was from the Chemistry section.

Basically we put 2 ice cubes each in 5 small plastic cups and placed them in various spots around the house and garden.  The girls then predicted for each cup how long it would take the ice to melt.

They wrote down where they'd put the cups and the time they'd predicted for the melting, then started the stopwatch.  The ice took much longer than expected to melt - the first one - out in the full sun, took 28 minutes (a lot longer than the expected 6 minutes!).  The last one to melt was kept in a dark cupboard and the ice lasted a full hour longer than the one outside!

The girls found the experiment interesting  - particularly since the results   were different to what they had expected. It was a nice simple one to set up and do too!

I think this book is going to have some great ideas for us to do some fun experiments this year.

On the curriculum for both girls school year is conducting science experiments - planning, predicting and discussing how the experiment is conducted and the results. The year 3 curriculum (for our younger daughter) also deals with the change of heat between solid and liquid as a result of heat, so this experiment in particular is relevant there.  It also sparked a second experiment to discover what difference placing the cup of ice under the ceiling fan makes!

Do you have any simple science experiments you've done with your kids at home?