Fun With Acids and Bases – How to Use Red Cabbage as an Indicator

Red cabbage acid base indicato original

Do kids want to learn about acids and bases? If they’re like my kids then probably yes in theory – but in practice, “Not right now, thanks Mummy, I’m just finishing this game on Grid Club/making this cardboard helmet/playing my guitar”.

Do kids want to play with colourful potions? Absolutely! And once you’ve ignited their curiosity, of course they’ll want to know all about it!

Bring on the red cabbage and those old faithfuls, vinegar and bicarbonate of soda…

What You Need

  • Red cabbage (we used half a head)
  • Water (the book says to used distilled water, but we used tap)
  • Saucepan
  • Stove Top / Hot Plate
  • Glass jars/glasses etc (to pour the cabbage water into)
  • Household substances to test eg vinegar, lemon juice, bicarbonate of soda, soap
  • Marker pen or dry wipe marker (optional) to label the jars
red cabbage acid base indicator homeschool science

What You Do

  1. Roughly chop the cabbage and boil it in water for about 10 minutes.
  2. Drain (and discard/eat) the cabbage, reserving the water.
  3. Pour the water into as many jars/glasses as you have substances to test, plus one as a control.
  4. Add one substance (e.g. lemon juice) to each jar of purple cabbage water. Label the jar so you don’t forget what you’ve added.
  5. Observe any colour change, comparing against the control cabbage water (to which nothing has been added).

What Happened

The water the cabbage has been boiled in is dark purple.

C and J both chose to add vinegar  to their first jar, which turned the cabbage water a pinkish colour. Then they predicted (proper science!) what would happen when they added lemon juice, and were happy to confirm their hypothesis that lemon juice also turned the water pink.

The effect of adding bicarbonate of soda was more subtle.  We had to scoop up a small amount of the liquid with a teaspoon to fully appreciate the change – the water took on a blueish hue.

Red Cabbage Acid/Base Homeschool Fun

Soap turned the water very slightly blue, and soy sauce had no noticeable effect.

What We Might Do Next Time

What we forgot to try (there’s always something!) is adding vinegar or lemon juice to our bicarbonate of soda water.  If you get the quantities right, this should turn the water back to the original (purple cabbage) water colour.

There are also lots of other substances we might test – orange juice, milk, Coca-Cola, tomato sauce…

How Does It Work?

Science Experiments Book

I’ll hand you over to the Science Experiments book here:

“An acid is a substance that produces positively charged particles made of oxygen and hydrogen, called hydronium ions, when dissolved in water…

A base is the chemical opposite of an acid.  Bases produce negatively charged particles in water, called hydroxyl ions….

Cabbage water [is an indicator, which means it shows] whether a liquid is acidic or basic. [It changes] colour because the structure of [its] molecules changes depending on the amount of hydronium or hydroxyl present.”

red cabbage acid base indicator homeschool science

Taking It One Step Further

For this you’ll need a pack of pH-testing litmus paper (£2.76 on Amazon).

red cabbage acid base homeschool science

I gave the children a book of litmus paper and they dipped a fresh piece in each of their cabbage water jars. They compared the colour the paper turned with the colour scale on the book, to obtain a pH value.

Red cabbage acid base indicator homeschool science

I explained that pH is a measure of the acidity or alkalinity of a solution. (Bases that dissolve in water are called alkalis.) Acids have low pH’s, alkalis have higher pH’s.

red cabbage and litmus acid base indicator - homeschool science

C noticed by testing with litmus paper that our soy sauce solution was very slightly acidic.

Has anyone else tried this? Do leave a comment to let me know how it went or if you know of any other fun experiements with acids and bases!

More Hands-On Science Posts

How to Make Slime and Plastic

Fizzy Fountains

Copper-Plating a Nail

Thanks to Adventures In Mommydom for hosting Science Sunday!

Science Sunday

How To Make Slime and Plastic

Home Made Slime - Homeschool Science
This week we made our own biodegradable plastic and had hands-on (literally!)  fun with sticky slime.

Slime

You have to feel this stuff to believe it.  The children had way more fun playing with it than they’d expected.  Best of all, it’s so easy – five minutes to make, a whole afternoon of fun!

Home Made Slime - Homeschool Science

What You Need

  • Cornflour (cornstarch)
  • Food colouring
  • Water
  • Cup, bowl, spoon

What You Do

  1. Put a cup of cornflour (cornstarch) into a bowl.
  2. Slowly add water, stirring all the time, until the mixture becomes a sticky paste (add up to about half a cup).
  3. Add food colouring and stir to blend.
  4. Have fun with your slime! Notice how it both flows like a liquid and sticks together like a solid.

The Science

Slime is a “non-Newtonian fluid” because it doesn’t conform to Sir Isaac Newton’s rules about how liquids behave. It’s made of polymers – long chains of simple molecules.  When the chains are stretched out the liquid flows, but if you apply pressure the chains stick together.

How to Make Slime Collage original

What We Might Do Differently Next Time

This really is so easy. The only thing we’d do differently would be to be less concerned about the exact amounts of cornflour and water. You can always add more of either (or both). Cornflour is our new favourite science ingredient!

Home-Made Plastic

What You Need

  • Starch (eg cornflour/cornstarch, potato flour)
  • Glycerine
  • Vinegar
  • Food colouring (optional)
  • Aluminium foil
  • Wooden spoon/spatula
  • Old saucepan

How to make plastic - homeschool science

What You Do

  1. Mix together 1 tbsp starch and 4 tbsp water in a saucepan.
  2. Add 1 tsp glycerine and 1 tsp vinegar.
  3. Stir until blended.
  4. Put the saucepan on a low heat, stirring constantly.
  5. Observe the mixture change from a cloudy liquid to a clear gel.
  6. When the mixture is completely transparent and starts to bubble*, use the wooden spoon to spread it out on a sheet of foil.
  7. Wait a day for your plastic to set.
How to make plastic - homeschool science

What Happened

Watching the mixture turn into a gel was very cool. *Ours never became completely transparent or visibly bubbled (we made three batches) but the plastic turned out fine. (For our purposes! We weren’t planning any industrial applications.)

how to make plastic - homeschool science

I forgot to do step 6 for our first batch   (I’m not great at reading instructions) so our red plastic came out in globules that would do nicely as fake jam!

Then we made green plastic in the same saucepan, without washing it, which resulted in a gross concoction that might be given away with the Beano (I’ll spare you the photo). I had to make some nice fresh-looking blue in a clean pan after that experience. (The kids were out playing in the snow by this point but – hey – I was having fun.)

What We Might Do Differently Next Time

  • We might make some uncoloured plastic, to see if it turns transparent in the way the book describes.
  • We might experiment with different quantities of glycerine, which changes the rigidity of the plastic.
  • I wouldn’t use an ancient non-stick saucepan – bits of the non-stick coating came off in our plastic. The pan came completely clean after a soak so I’d use a regular, uncoated sort. Perhaps it’s time to invest in a dedicated science pan. 🙂
homemade_plastic_original (1) 2

The Science

Like slime, plastics are made from polymers. Their chain-like structure makes them flexible enough to mould while soft, then strong when set.

What Does Each of the Ingredients Do?

Starch contains polymers. Vinegar makes the chains stronger, and glycerine makes them more flexible.

The Book

Both these experiments come from Science Experiments: Loads of Explosively Fun Experiments You Can Do. We’re very much enjoying our journey through the book. A few of the experiments call for materials that are tricky or expensive to source (dry ice, powdered alum) – we’ll skip those for now – but most are inexpensive household items. I love the way the materials and instructions are clearly laid out with plenty of pictures.

More Hands-On Science

Fizzy Fountains – Diet Coke Geysers and Home-Made Lava Lamps

Copper-Plating a Nail

Science Sunday

We’re linking up with AdventuresInMommydom’s Science Sunday – thanks Ticia for hosting!

2 Fizzy Fountains

Fizzy fountains

Homeschool science is so much fun.  This week we made two very different fizzy fountains. On Monday we let off a diet coke and mentos geyser, and on Friday we created our own “lava lamp”.

Diet Coke and Mentos Geyser

I bought the supplies for this back in June 2012, when we were doing our rocket project, but the instructions for making a diet coke and mentos rocket were evidently too daunting for me to get around to doing it. So when the children recently asked if we could make a diet coke fountain, I was all ready to go.

What You Need

  • large bottle of soda (coloured, diet soda like Diet Coke is best – so you can see the spray, and the spray doesn’t make too much of a sticky mess)
  • pack of Mentos
  • paper/card or Geyser Tube
  • a large outdoor space

What You Do

The experiment couldn’t be simpler to explain. Dump a whole packet of Mentos into a bottle of soda, then stand well back.

The tricky bit is trying to get all the Mentos in at once. Cordie and Jasper experimented with various techniques using an empty bottle. What seemed to work best was loading the Mentos into a piece of paper which had been rolled into a loose cone, while holding a piece of card at the thin end of the cone to keep the Mentos from falling through. The card can then be slid away when you’re ready to set off the geyser.

How Did It Go?

Our Mentos-loading technique worked perfectly the first time. However, our geyser was only about a foot high. Maybe because the diet coke I’d bought for our rocket experiments was four months past its use-by date?!

coke and mentos geyser - homeschool science at navigatingbyjoy

But …we still had a tube of mentos left, so we tried again, this time with a bottle of caffeine-free diet coke I’d been saving to enjoy with a shot of rum at the weekend (I am so selfless in the cause of science). Unfortunately this time our Mentos-loading technique didn’t work so well.  No quick-fire round of mints exploding the surface tension of the coke – instead, the last 8 were hastily shoved in one by one before I scarpered to a safe distance.

The resulting geyser was double the height of our first attempt, but there was no danger of getting our hair wet, let alone the roof. (I felt a bit wistful as I removed my sou’ wester hat.)  But the kids – who hadn’t known what to expect – were impressed.

How Does It Work?

No-one knows for sure! The most popular theory is that the Mentos break the surface tension of the soda, releasing loads of carbon dioxide bubbles at once. These bubbles push all of the liquid out of the bottle in a fantastic explosion.  Steve Spangler Science has a more detailed explanation and some cool videos.

What Might We Do Differently Next Time?

  • use a Steve Spangler Geyser Tube (£4.45 at Amazon) to load the Mentos
  • try using store-brand diet cola (Tesco does 2 litre bottles for 17p)

We will spray our trees with coke yet!

Oil and Water Fizzy Fountain

We found this in Science Experiments: Loads of Explosively Fun Experiments You Can Do.

What You Need

  • plastic bottle
  • vegetable oil
  • water
  • food colouring
  • two effervescent tablets (containing citric acid and bicarbonate of soda)

fizzy fountains homeschool science fun

What You Dopouring water onto oil - homeschool science

  1. Fill a plastic bottle three quarters full with vegetable oil.
  2. Top up with water. (Observe how the water sinks to the bottom because it is denser than the oil.)
  3. Add a few drops of food colouring. (Wait a moment for the colour to sink through the oil, then appreciate the pretty effects as it mixes with the water.)
  4. Break two effervescent tablets in half and drop them into the bottle.
  5. Loosely screw on the bottle top. (Watch your fizzy fountain start to work.)

How Does it Work?

When the tablets dissolve in the water, they give off carbon dioxide. Bubbles of this gas float up through the bottle. When the bubbles attach themselves to blobs of water, the blobs and the bubbles together are less dense than the oil, so they rise up to the surface. There the bubbles pop, and the blobs of water sink back down through the water again.

What We Might Do Differently Next Time

effervescent oil and water fountain

This was a fun experiment – we would do it again. I might make a few changes though:

  • use a smaller bottle (less oil – cheaper!)
  • use less food colouring. We used red, blue and green which together turned the water dark brown.
  • use indigestion tablets instead of (orange) vitamin C tablets (another reason why the water turned brown?)
  • shine a lamp through the bottle
  • add glitter to the fountain
  • experiment with different kinds of oil e.g. olive oil

Bonus Fun

We hunted out Big J’s lava lamp and enjoyed watching the pretty patterns as warmed wax floated up to the top and then sank again as it cooled.

What Next?

Next week we’re going to investigate polymers, making slime and plastic. Sounds fun!

Learning How To Start

project based homeschooling at joy homeschooling blog

In her blog this week Lori Pickert has quoted one of my favourite paragraphs from her book, Project-Based Homeschooling:

“Many adults, let alone children, stall in the information-gathering stage of a project.  They keep collecting inspiration and ideas without ever moving forward to the point of making something of their own.  Forget about finishing – they can’t start.”

Lori’s post is actually about the difference between good and bad persistence, and in particular how “you’re not teaching the kids persistence forcing them to complete something *you* want them to do.”  But the quote about not being able to start totally resonated with me (in quite an uncomfortable way!) when I first read it in her book, and one of the many beautiful and unexpected benefits I’m getting out of project-based homeschooling is that my kids – unhampered by years of formal schooling – are showing me how to start!

Since I’ve let go of trying to control every aspect of the learning process, something magical has happened around here. My kids are learning so much more!  Cordie (8) has always been an independent self-starter, so it’s in Jasper (7) that I’m noticing the biggest changes.   We have lots of creating space around our home but it wasn’t until I read Project-Based Homeschooling that it occurred to me that Jasper didn’t have his own desk space in our main living area. We have a large craft desk but that has pretty much been colonised by his prolifically-creative big sister, whereas Jasper had made his own a tiny table housing our desktop computer and – guess what – he wanted to spend all his time on the computer!

As part of our reorganization  he has his own desk and – wow! – is he using it. He’s initiated and completed more creative and science mini-projects this week than I would probably have got round to doing in a month (term??)! All thanks to that little space of his own and the magical power of “project-time”. I think the highlight of my week was when he sighed contentedly in the bath one evening and told me, “when I grow up I want to be a scientist (and a quadrillionaire)” – the millionaire/quadrillionaire bit always comes up, but this was the first time I’d heard Jasper talk about wanting to do anything apart from design/test computer games.  Not that I have anything against him working in games, but it made my heart sing to think that he’s beginning to like science (anything!) as much as he enjoys computer games!

Here’s what my children have taught me this week about “starting”: don’t over-think, over-plan, wait for the perfect moment or worry about the mess – just do it!  And when you do, you learn heaps, have stacks of fun, and – when you’re surfing a wave of  authentic, happy enthusiasm – the preparation and clearing up doesn’t take nearly as long as you thought it would.  🙂

project based homeschooling at navigating by joy

A Day In The Life of a British Homeschooling Family

a day in the life of a british homeschooling family - navigating by joy

Like many homeschoolers, there is no “typical” day in our household.  Our week is loosely structured around external activities like sports classes and our weekly homeschool group, and there are certain subjects that I aim to cover in a week, but other than that,  I like the flexibility of a routine rather than a fixed schedule.

Having said that, here’s an example of a typical, non-typical day!

530am I get up.  I’m not normally this early!  But it’s such a beautiful morning already  I decide I’ll enjoy some quiet time to myself.

645am I go back to bed and meditate/play Words with Friends until 730. I love how my iPhone lets me have a permanent scrabble game going with my mum who lives in Wales!

830am We’re having poetry tea with friends later, so I bake some gluten free/sugar free cookies with the children.  J has been so much calmer since we reduced his dietary sugar, gluten and dairy five months ago (on the advice of a complementary health professional) .  Since most bought products are either sugar or gluten free, I find myself baking a lot.  I’m not an experienced cook, so the recipe substitutions I make can be a bit random, as can the end products. Luckily the children are very forgiving.

850am As we put the eggs away, J asks if we can make pancakes.  I promise him that if he gets on with his maths and English without any fuss, there’ll be time to make some before we set out for our friends’ house.

855am Incentivized by pancakes, J physically drags me into my office, where C and J do most of their individual schoolwork. He does copywork from “Fox In Socks” and we practice phonics and spelling using The Wand.  For today’s maths we look at negative numbers in Primary Grade Challenge Math.

915am  J makes pancake batter. He and C got very good at making pancakes shortly after we changed his diet – gluten and sugar free English pancakes, made with goats’ milk, work really well!

10am We arrive at our friends’ house.  C and J run off to play with the other children (aged 12, 10 and 9)  while I catch up with my friend.  Later we sit at a beautiful table and eat cookies, drink tea from fine cups and saucers, and take turns reading poems aloud. These are the friends who introduced us to the Brave Writer lifestyle, and I love sharing Poetry Tea with them; it’s such a pleasure hearing the poem each person has chosen.

I read “A Summer Morning” by Rachel Field, because even though it’s only May, temperatures have been in the 80’s today.  After the weather we’ve had in England recently, it definitely feels like summer!

1130am On the way home we stop off at the park to enjoy the sunshine.

12pm We make another stop, this time at the garden centre, to pick up some compost: it’s finally safe to put the tomato and pepper plants outside!

1230pm Lunch.  J learned how to make cheese and ham tortilla flatbreads at our homeschool centre yesterday; he decides to make them again today. It requires a brick, apparently.  C obligingly finds one in her den at the end of the garden.  J teaches C how to make his new dish.  I do the bit at the hob, involving flattening the tortilla between the griddle pan, a saucepan and a tea towel-wrapped house brick!

homeschool gardening - navigating by joy

1pm C waters her vegetable patch while I plant out the tomatoes. J bounces on the trampoline then retreats from the heat inside.

phantom tollbooth - navigating by joy homeschoolers145pm C and I go to my office for her English and maths. We continue our discussion of literal versus metaphorical meaning using The Arrow and our novel, The Phantom Tollbooth. We discuss what clichés are and pick out a few from a list I had printed out; then we start an exercise from The Arrow, creating a story taking metaphoric meanings literally. It’s about a king standing on the tip of an iceberg.  C enjoys this so much that when I suggest finishing, she begs to do a bit more! Always a good sign 🙂  We finish by reading aloud a chapter of The Phantom Tollbooth.

We use Primary Grade Math Challenge for maths and C answers the level 2 questions on negative numbers.

245 pm Science: we continue our space travel project. The children make edible space shuttles following directions in this NASA Educators’ Guide.

We watch a You Tube video of the shuttle taking off and look at a printables of the parts of the space shuttle and the sequence of take-off, orbit, and landing.  C and J then assemble their own shuttles using bread, carrot, celery and hummus.  I video them “narrating” their own take-off to landing sequences on my iPhone.  C leads the narration but J contributes a piece of information he remembered from our recent visit to the Kennedy Space Centre – something I hadn’t even realised he’d taken in at the time – I love it when that happens!

edible space shuttle - navigating by joy homeschoolers

J follows his space shuttle snack with a plum from the fruit bowl, and then asks me to point out to him the plum tree in our garden. We look at the hard, grape-sized plums on the tree and I tell J how I ate the sweetest, juiciest plum from it on the day we moved into our house on 31 July 2007.  He said he is going to keep an eye on the plums’ progress. Sometimes I wish I made more time for formal nature study in our homeschool; then I realise that thanks to the huge amount of free time they have to spend outdoors, C and J are actually quite in tune with nature and the seasons.

boudicca - navigating by joy homeschoolers4pm History: I decide to squeeze in a bit of The Story of the World before swimming classes. J groans (he never likes the idea of history) but he soon joins C pleading for more when I stop after half a chapter on the Celts.  Half a chapter is all the Celts get in The Story of the World, but as they are our bit of ancient history, we’re spending a bit longer on them than our curriculum suggests. I read from our living book on Boudicca while C spontaneiously makes a Boudicca “doll” from a feather the cats brought it.

5pm C and J go to their swimming classes while I squeeze in half an hour in the gym. When the children were at school, exercising often felt like a chore.  Now I cherish my gym time!  We eat dinner at the sports centre cafe, and C and J have some time jumping around in the soft play area.

7pm We go straight from the sports centre to take C to Cub Scouts (where she is one of only two girls). Normally this signals the end of my day’s “work”, but Big J’s commuter train is delayed tonight so J and I go back out to collect C from cubs at 830.

930pm I’m relaxing with an alcohol free beer and watching The Vampire Diaries.

A good day!

Elementary Chemistry: Copper-Plating a Nail

We jumped into practical chemistry today with this experiment from Wholly Irresponsible Experiments.

To be honest, for all my recent intention to become more hands-on with science, I had planned to ease gently back in after our week away skiing, by watching Chemistry, A Volatile History. I hadn’t counted on C (8) and J (6)  being so inspired by what they saw that they wanted to leap straight into being chemists themselves!  (There’s nothing like a break to recharge the homeschool enthusiasm!)

As soon as the end credits on the documentary began to roll, J jumped off the sofa and headed towards the bathroom, blithely announcing he was “off  to make some potions”.  Remembering that a similar impromptu potion-making session had got through the large part of a £35 tube of my Laura Mercier foundation,  I quickly grabbed Wholly Irresponsible Experiments and began setting up this easy and fun experiment.

What You Need

  • 12 dull copper coins
  • 150 ml (2/3 cup) vinegar
  • 1 tsp salt
  • Small bowl (we used a ramekin)
  • Teaspoon
  • Iron nail (ungalvanised) or 2
  • Kitchen paper

What You Do

  1. Pour the vinegar into a small bowl.
  2. Stir in the salt.
  3. Put the copper coins into the bowl so that they are completely submerged.
  4. After 5 minutes use a spoon to remove the coins
  5. Put the nail into the bowl. Notice little bubbles begin to form on it.
  6. After 30 minutes use a spoon to remove the nail

What Happens

The nail comes out copper coloured! If you have a second nail you can compare the two.

The Scientific Explanation

Copper from the coins goes into the salt and vinegar solution and attaches to the nail, producing a copper-plated nail.  For more on the science see this site.

Verdict on the Experiment

A resounding success.  Fast, easy and very cool!

Beginning Chemistry

It’s time to get more hands-on in our science.  Last term we followed REAL Science Odyssey’s “Life”  curriculum;  C and J loved making jelly cells and blood, acting out red blood cells moving around a giant’s respiratory system, and learning about human digestion and bones. But since the Life curriculum had moved onto worms and molluscs their interest was beginning to wane, besides which it’s entirely the wrong season to be hunting snails or waiting for butterflies to emerge from chrysalises.   The upshot is, we’ve put our half-finished animal kingdom lapbooks aside for now and dived into chemistry!

Research

I spent a weekend thumbing through some chemistry books on our shelves – Robert Winston’s It’s Elementary! Putting The Crackle into Chemistry  and Irresponsible Experiments  – and the REAL Science Odyssey Chemistry curriculum I’d bought in the last Pandia Press sale.  “It’s Elementary” is wonderful but doesn’t offer much in the way of hands-on science, and “Wholly Irresponsible Experiments” is full of fun activities, but from experience I know I need to be guided by some sort of curriculum otherwise all that fun hands-on stuff tends to fall by the wayside.

REAL Science Odyssey Chemistry (1)

The RSO chemistry curriculum is very rigorous in its application of the scientific method and contains lots of practical activities.   The worksheets are mainly geared to older children, so we’re going to focus on the experiments, backed up with plenty of discussion.  We’ll still follow the scientific method –hypothesis, observations, conclusions – but my overriding intention is to get the children excited about science!

“Potions”

C and J are big Harry Potter fans so I knew this “potions” lesson would go down well. We started out with three separate bowls containing:

  • confectionary (icing) sugar
  • baking powder
  • baby powder

First we used our physical senses to examine the powders.

Then we tested how each powder reacted when we added small amounts of various liquids:

  • Water
  • Vegetable oil
  • Vinegar
  • Blue food colouring

Mostly the liquids were added one at a a time to the powder, but sometimes we added more than one thing, like:

  • Food colouring and water
  • Oil and vinegar
  • Oil, vinegar and food colouring

How Did It Go?

The children loved it.  J was especially delighted to have chosen to administer the test on baking powder, which fizzed very gratifyingly when vinegar was added to it!

What Would I Do Differently Next Time?

Although they started out very enthusiastic, by the end of the experiment the children were a bit weary – there were a lot of tests, and they had to wait while I washed up the glasses in between each one. If I were doing this again I would probably spread it over more than one day or leave out some of the tests.  Science works best in bite-size chunks in our house at the moment.

What Next?

The RSO Chemistry curriculum moves on next to a discussion of atoms and then introduces the elements. Before we go onto that, I’d love to find a good living book on the history of chemistry.  It took a long time for alcehmists-turned-scientists to discover that the world is made of elements, and the story of how they did is fascinating, as I found out when I recently watched the BBC documentary Chemistry – A Volatile History. Wouldn’t it be fun to learn about atoms and the elements as the final piece of a detective story that puzzled great minds for centuries!

My Library Thing

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