Category Archives: Science

Creative Science with Ice, Salt and Colour

May 11, 2013Sciencegrade 2, grade 3, iceLucinda

Science Play Ice Salt and Colour

This week we played with salt, ice and liquid watercolours. It was one of those cool activities that combines science and creativity, and has everyone happily engaged for hours.

What You Need

One or more plastic containers – we used several, of different shapes and sizes. Ours had lids to make them easier to stack in the freezer.
Water
Salt
Liquid watercolours or food colouring
Plastic pipettes
Tray or dish to stand your melting ice in

science fun with salt ice and liquid watercolour

What We Did

I filled the containers with water and left them in the freezer for a couple of days.

We talked about the ways ice melts. The children said heat melts ice, so our ice would eventually melt if we left it out of the freezer. Or we could speed up the melting process by pouring on warm water. I asked them how we deal with icy paths in winter and they shouted “salt!”. We recalled how we added salt to ice to quickly freeze juice into a sorbet, and how that worked because the presence of an impurity (like salt) lowers the freezing point of water.

Then I handed over the salt and the liquid watercolours and let the children experiment.

They started out by sprinkling salt on the ice and noticing how the salt melted the ice where it came into contact with it. (Actually they started out by licking the ice – they do like to engage all their senses… I made sure this happened only the once, before any salt or paint had been introduced!)

Then C(9) had the idea of colouring her salt before sprinkling it on so she could follow its path. But she found the salt difficult to sprinkle when wet, so she decided to sprinkle and then quickly add colour. Soon she realised that she didn’t have to be so quick, because the colour always followed the path of the melting ice.

Fun with salt ice and liquid watercolour

More colours were added…

science fun with salt ice and liquid watercolour

And great fun was had by all!

I loved seeing how differently each child interacted with their ice. While C(9) enthused poetically about “glistening cataracts”, J(8) wore his best would-be world-dominating mad scientist expression as he attacked his with three purple pipettes at a time, shouting “I’m going to burn a hole RIGHT THROUGH THE HEART of it!”

Salty icy tunnel

Lots of creative expression, and some science too!

science fun with salt ice and liquid watercolour

Variations

Using food colouring instead of liquid watercolour – I think I added too much water to our liquid watercolours – they were a bit wishy washy (not that the children noticed). While they were busy making cataracts and chasms, I privately experimented with using gel food colours instead. These highlighted the paths of the melting ice much more clearly, but one drop went a long way so the children wouldn’t have had nearly as much fun if we’d used these – their ice would quickly have been saturated with colour. The vibrant colours make for quite a cool demonstration, though.

Gel food colour salt and ice — Gel food colour, salt & ice

Another scientific variation would be to experiment with different types of salt – rock salt, for example.

Science play ice salt and colour

Further Resources

Our arty science project was inspired by The Artful Parent.

Ice Tunnels: Bring on the summer fun! I found this after we played with our ice.

I hope you enjoy playing with colourful salty ice as much as we did!

Homeschool Pond Study – Late April

May 4, 2013Nature Studypond study, seasonsLucinda

homeschool pond study

The more we visit our pond, the more we enjoy it. These days, when it’s so easy to travel far and wide, it’s such a treat to spend time becoming intimately familiar with one special place. I continue to be so appreciative of Angelicscalliwags for inspiring us to to this.

Courting Swans

The swans were the stars of the show at our pond this April. Back at the start of the month we noticed that they had built a nest on the island.

The following week we witnessed some very beautiful swan rituals. C(9) said it looked like they were synchronised swimming.

Swans mating ritual homeschool pond study

There is a final photo in the series but I’ll spare your blushes and show you this preening close-up instead!

Preening swan

Bird Ringing Scheme

Later, one of the swans gave us an excellent view of its leg, on which it wore a metal ring. By zooming in on the photo, we could read that the ring was labelled “BTO British Museum Nat Hist London SW7”.

swan's leg - homeschool pond study

ringed swan homeschool pond study

swan ring - homeschool pond study — Example ring from the Ringing Scheme website

We looked this up when we got home, and learned about The Ringing Scheme, which allows members of the public to report sightings of ringed birds.

The rings on the Ringing Scheme website had numbers on, but we couldn’t find a number on our swan’s ring. C(9) has emailed the Ringing Scheme to find out more about this.

Nesting Coots

The coots are also nesting. They’ve picked an excellent spot, at the edge of the pond but very well concealed. I was only able to get this (very zoomed in) photo from the far side of the pond.

nesting coot - homeschool pond study

Our female coot has been sitting on her nest for the last few weeks. The incubation period is just over three weeks so we should see coot chicks at our pond very soon! (When we were wondering about the correct name for the young coots, J(8) suggested that they should be called “cuties”. That one may stick :-))

The male coot, meanwhile, has been much less shy.

coot - homeschool pond study

Watercolour Art

We admired how green the trees and plants around the pond have become, and brought a few small samples home to paint.

spring branch watercolours - homeschool pond study

braiding willow - homeschool pond study — C(9) loves to braid willow into “ropes”

Evening visit to the pond — We visited the pond at 7pm one evening as we dropped C(9) at a Cubs walk. The light was gorgeous

Testing pond temperature — Testing the pond temperature

Den building in the woods — Den-building in the woods by the pond

Homeschool Pond Study – Mid-April

April 15, 2013Nature Studypond study, seasonsLucinda

swan - homeschool pond study

Life at our pond is hotting up. We’ve noticed new signs of spring each week since our first trip. One of the most welcome is the temperature – so mild, we were actually able to sit on our blanket and quietly watch the pond for a while, which was heavenly!

Nesting and Mating

This week’s big excitement was a swan nesting on the island. At least it looked like it was sitting on a nest. When it briefly got off the nest we didn’t see any eggs, but we supposed they were buried within the nest to stay warm? (Or was it practising??! We’re all learning around here!)

nesting swan - homeschool pond study — Nesting swan

homeschool pond study — C(9) sketching the nesting swan

swan sketch - homeschool pond study — C(9)’s nature journal

C(9) sketched the nesting swan in her nature journal while J(8) got busy with our new gadget, a digital aquarium thermometer.

Testing pond water temperature — J(8) tries out the gadget

child's nature journal — J(8)’s nature journal

We saw a coot swoop low over the pond with a short willow branch in its beak. It landed near the base of a willow tree where we later spotted it on its nest.

Some of the mallard ducks had found mates – we counted at least two pairs – but the male mallards still heavily outnumber the females.

Mallard ducks - homeschool pond study — The males seemed to go round in gangs!

Identifying Our Birds

We’ve seen one pair of geese at our pond with very unusual markings. When we got home we used the excellent online RSPB bird identifier to work out that they are Egyptian Geese (how exotic!). Apparently these geese were introduced to ornamental ponds and have now begun to breed in the wild.

egyptian geese - homeschool pond study.JPG — Egyptian Geese

This very sweet little thing was dabbling around the “moat” by the island on its own. It was very tame, and quite talkative. The RSPB bird identifier wasn’t able to help us with this one. Our best guess is that it’s a juvenile of some sort. If you have any idea what it is, please do let me know!

Mystery duck collage — Sweet little mystery duck

We also saw a pair of jackdaws and – far off in the distance – a pied wagtail (thank you, RSPB identifier!).

jackdaw - homeschool pond study.JPG — Jackdaw – one of a pair

pied wagtail - homeschool pond study — Pied wagtail – a bit blurry in the distance

identifying birds - homeschool pond study — Using the RSPB bird identifier

Trees

The willow tree that J(8) has chosen to study has begun to grow leaves.

new willow leaves - homeschool pond study — New willow leaves

We brought a bit home to sketch. I love how when you draw something you see it in a totally new way. Mixing up watercolours helped us focus on the leaf colours, too.

Nature study watercolour

watercolour willow branch - homeschool pond study — J(8)’s watercolour willow branch

For more outdoor fun, visit Country Kids from Coombe Mill.

Clay Model Of the Earth’s Layers

April 13, 2013Geography, ScienceEarth ScienceLucinda

How to make a clay earth

Making a 3D model is an easy hands-on way for kids to learn what the Earth is made of.

We read about the Earth’s layers, to begin with, in The Magic Schoolbus – Inside the Earth.

the magic school bus inside the earth

Then we grabbed some clay and the children used the pictures from the book to make their own models. (I was going to make one too, until I realised how much plasticine we were going to get through!)

First roll a small ball of clay for the solid metal inner core.

The inner core is about 1,500 miles in diameter. We used an atlas to calculate that this is equivalent to the distance from London to Madrid (or San Diego to Memphis).

diameter of the Earth's inner core

Next the melted metal outer core.

how to make a clay earth

Then the solid rock mantle.

how to make a clay model of the earth

Followed by the Earth’s crust (one layer in our models, but in reality, layers of sedimentary, metamorphic and igneous rock). We looked at these when we simulated the rock cycle with crayons.

how to make a clay model of the earth

And finally, the oceans and continents.

how to make a model clay earth

When you’re done, use a sharp knife to cut your Earth in half to reveal it in cross-section.

how to make a clay model of the earth

how to make a clay model earth

how to make a clay model Earth

C(9) used a toothpick to label the layers.

how to make a clay model of the Earth

Top Tips For Making A Clay Model Earth (What We Might Do Differently…)

Use play dough rather than plasticine, especially in winter. Cold plasticine takes a long time for little hands to mould.
If you do use plasticine (we did), warm it up in the microwave – this makes it much easier to work with. On the plus side, our clay Earths will last as long as the real one!
Don’t make your inner core too big. We were surprised how much more clay was required to make each successive layer. (Good learning!)

Hat Tip

My original inspiration for this came from Meet the Dubiens – Jill’s lovely photo was one of my very first Pinterest pins.

Further Resources

Online tutorial on the Earth’s layers

Earth’s layers printable

How to make a clay model earth

I’m appreciatively linking up with:

History and Geography Meme at All Things Beautiful

Science Sunday at Adventures in Mommydom

Hobbies and Handicrafts at Highhill Homeschool

Collage Friday at Homegrown Learners

Look What We Did at Hammock Tracks

Weekly Wrap Up at Weird Unsocialized Homeschoolers

Money Saving Monday at Life’s Little Adventures

Edible Science With Ice And Salt

April 9, 2013ScienceChemistry, iceLucinda

hands-on experiment salt and ice heat transfer

Here’s how you can make a tasty sorbet in five minutes while learning about the effect of freezing point depression with ice and salt.

C(9) found the experiment in our Science Experiments book. We had all the supplies so we were ready for some spontaneous learning fun!

hands-on experiment salt and ice heat transfer

What You Need

Orange juice (or other juice)
Crushed ice (or snow)
Salt (about 4 tablespoons)
2 ziplock bags, one larger than the other
warm gloves

What You Do

1. Pour orange juice into the smaller ziplock bag. Squeeze out excess air and seal.

hands-on experiment salt and ice heat transfer

2. Place the bag inside the larger ziplock bag.

3. Fill the larger bag with crushed ice so that it surrounds the orange juice bag.

4. Add salt to the ice. The book suggests 4 tbsp but we just sprinkled liberally.

5. Squeeze out excess air and seal the large bag containing everything.

6. Gently massage the bag so that the salty ice is constantly coming into contact with the orange juice bag.

7. Continue squishing for 5-10 minutes, observing the changes in how the orange juice looks and feels.

What Happens

The orange juice gradually solidifies and turns into sorbet!

hands-on experiment salt and ice heat transfer

The Scientific Explanation

Adding an impurity (salt) to ice lowers its freezing point. The ice wants to melt back to water, but to do this it needs to absorb heat from somewhere – in this case, the orange juice. Heat is transferred from the orange juice to the ice, freezing the orange juice.

This is an endothermic process (heat is absorbed).

For a detailed molecular explanation of why salt melts ice, see this article.

What We Might Try Next Time

We ended up with a very healthy snack, but for a treat we might make a sweeter sorbet by adding sugar. (Here are the ingredients for a simple lemon sorbet, and a whole list of delicious sorbets here – courgette (zucchini) sorbet looks interesting!) We might even try making ice cream in a bag.

hands-on experiment salt and ice heat transfer

Further Resources

Why Does Salt Melt Ice?

An “Ice Energy” lesson plan (includes ice cream recipes)

Science Experiments: Loads of Explosively Fun Experiments You Can Do

For more hands-on learning fun, head over to Hobbies & Handicrafts at Highhill Homeschool, Homeschool Review at Hammock Tracks, and Science Sunday at Adventures in Mommydom.

Homeschool Pond Study

April 7, 2013Nature Studypond study, seasonsLucinda

Homeschool pond study collage

Angelicscalliwags’ One Year Pond Study has had me excited about nature study in a way that hasn’t happened since … well, ever! Like angelicscalliwags, we’ve tried using an assortment of books, blogs and curricula for inspiration but nothing seemed to stick, so I contented myself knowing that with daily dog walks in the woods and by the river, summers at the beach and hours playing in our garden, C(9) and J(7) have plenty of opportunity to experience nature first hand.

But the idea of observing a local ecosystem regularly over the seasons really captured my imagination. So a couple of weeks ago we set off to get better acquainted with our own beautiful local pond.

I didn’t have any agenda for our first visit to the pond, other than to let the children explore and for me to observe what interested them. They were keen to take their nature study notebooks which I’d retrieved from the back of a shelf (last entries, May 2011 – ahem!)

What is a pond?

One of C(9)’s first questions was “Why do we call this a pond and not a lake?”

When we researched the answer later, we discovered some experts say that the difference is just about size, while others say it has to do with depth: ponds are shallow enough for plants to grow across the entire pond bottom. This area where plants can grow is known as the “photic zone”, meaning the sun’s rays can reach the bottom.

We also discovered that a person who studies bodies of fresh water is called a limnologist, from the Greek “limne” meaning “pool” or “marsh”.

Animal Life

We saw mallard ducks – “about four male ducks for every female”, C(9) noted in her journal.

A pair of Canada geese.

canada geese - homeschool pond study — Canada geese

A moorhen.

moorhen - homeschool pond study — Shy moorhen

A coot.

Two swans.

swans - homeschool pond study — Stately swans

Even evidence of moles – our puppy (happy to be finally let out of the car once we were safely away from the swans) was especially interested in these!

molehills - homeschool pond study

Plant Life

We saw daffodils in bud.

daffodils in bud - homeschool pond study — Daffodils in bud

And in bloom.

daffodils - homeschool pond study — Daffodils in bloom

J(7) picked a willow tree to draw.

winter willow tree - homeschool pond study — J(7)’s willow tree

drawing of willow tree - homeschool pond study — J(7)’s nature journal

Scientific Investigations

C(9) tested the temperature of the water and was surprised to discover that at 5℃ (41℉) the pond was warmer than the air (2.9℃ /36℉).

Pond temperature has higher resilience than air, so it is slower to lose heat following cool air conditions. While air may have high daily temperature variation, water remains relatively constant. (Now we know why we often see steam over the river on winter mornings.)

An unexpected bonus – Frogspawn!

We struggled to find a benchmark to measure the water level in the pond, but we know it must be pretty high because the surrounding meadow area was covered in large puddles. It was in one of these puddles that we were excited to discover a jelly-like substance with lots of little black dots in – frogspawn!

My mum said experts are concerned about frog reproduction this spring because with the late cold snap, ponds are too cold for frogspawn. Well our local frogs had found a solution – we just hope the puddles don’t dry up too soon!

frogspawn in a puddle - homeschool pond study — Frogspawn in a puddle

Also in the unexpected category – C(9) found a solitary egg drifting around the edge of the pond!

egg - homeschool pond study — The mystery of the egg

An Island

Our pond is in the middle of a popular dog-walking area, so we were find a tiny island which is close enough to shore for us to observe, but provides a small wildlife sanctuary from humans and their pets.

Surprising local history

When we looked up the name of our pond (which is in the next village, about 5 minutes’ drive away) we discovered some fascinating local history: until the 1970’s, naked bathing was permitted there! There were changing huts (for those with more modesty, we speculated?) and even a lifeguard in attendance at 630am on summer days. How times have changed since I was a child!

nature journal - homeschool pond study — C(9)’s nature journal

What a great time of year to begin a pond study. After a long winter with nothing much happening, nature is preparing to burst into life before our eyes. And as we braved the snow flurries (on 25 March!) I imagined how pleasant it will be to spend time pond-side when the spring sunshine finally arrives!

Thank you, again, for the inspiration, Claire and family!

To see what other homeschoolers have been doing this week, visit Adventures In Mommydom’s Science Sunday link up, and for more outdoor kids fun go to Country Kids from Coombe Mill and Outdoor Play Party at Learning For Life.

How to Simulate the Rock Cycle with Crayons

March 31, 2013Geography, ScienceEarth Science, geologyLucinda

Rock Cycle

We’ve done two hands-on earth science projects this week – on Monday we made model planet Earths out of clay, and on Thursday we simulated the rock cycle using wax crayons. Both were great fun, and both reminded me that these kind of projects take more time and effort than I anticipate when I read about other people doing them!

This post is about our experience doing the rock cycle. I hope my usual “what we might do differently next time” section will benefit you!

Before the Activity

We’ve been learning about the rock cycle and different types of rock over the last few weeks. We’ve watched Brainpop videos about weathering and erosion, and discussed how we might simulate weathering if we were using crayons to represent rocks. I’ve also been strewing rock samples from the collection I bought – just one or two at a time.

By now, all of us have Mr Lee’s Rock Cycle Rap stuck in our heads (highly recommended. I was so vociferous in my appreciation of this 6th grade teacher that J(7) asked me “Are you in love with him, Mummy?”). We also enjoyed this Song of the Rocks.

Just before we did the activity we watched the Rock Cycle Brainpop video and looked at pictures of the cycle in National Geographic Kids Everything Rocks and Minerals.

I strewed three rock samples on the table and told the kids one was sedimentary, one metamorphic and one igneous. They examined the rocks and correctly identified the smooth, glassy one as igneous rock Obsidian. (Cue much speculation about whether they could create a Nether Portal.) We didn’t say much more about the rocks – we’ll come back to them when we explore rocks in more detail.

What We Used

wax crayons in 3 contrasting colours (we used two of each colour, which made plenty of “rocks”)
sharp knife or grater (or pencil sharpener – see below)
tin foil (or metal cupcake cases)
very hot water
rolling pin or heavy book
candle (optional)
iced water (optional)
kitchen paper (optional)

Simulating the rock cycle – What you do

1. Grate or chop the crayons into small pieces, keeping the colours separate.

This represents weathering and erosion.

2. Sprinkle a layer of each colour crayon into a small piece of tin foil.

This is the laying down of sediments.

Fold up the foil (or put another piece on top) and press down on it very hard.

This simulates the pressure that creates sedimentary rock.

rock cycle

Unwrap your foil and examine your sedimentary rock.

3. Rewrap your squished crayon (sedimentary rock) and heat it by dunking it in very hot water for a few moments, then squish it some more. You could also use other metamorphic crayon-rocks or igneous crayon-rocks to make your metamorphic rock.

rock cycle

This represents heat and extreme pressure inside the Earth, which creates metamorphic rock.

rock cycle

4. Rewrap your heated, squished “metamorphic rock”. This time dunk it in the very hot water for long enough for the crayon to melt completely. Alternatively, briefly hold your foil packet in a candle flame which will melt your crayon more quickly. (Again, you can also use sedimentary or igneous crayon-rocks to make igneous crayon-rocks.)

The melted then cooled crayon represents igneous rock.

rock cycle

We let some of our melted crayons cool slowly, as would happen when magma cools slowly inside the Earth to create intrusive igneous rocks. We dunked other melted crayons (in their foil packet) in icy water to represent the fast cooling that takes place when lava cools outside the Earth, creating extrusive igneous rocks.

What We Might Do Differently Next Time

Use metal cupcake cases as recommended by Phyllis (whose post I only just found, unfortunately!). This would be much easier than unwrapping the tinfoil packets (we ended up using fresh pieces of tinfoil at each stage, and sometimes our “rocks” broke as they were unwrapped). Plus you’d get to see the melting process.
Use a pencil sharpener to “weather” the crayon pieces (another hat tip to Phyllis). This sounds much easier than messing around with knives and graters!
I like to involve the children at every stage, but I think next time I’d have a pre-prepared stash of weathered crayon pieces to add to the bits they make. “Weathering” takes a long time!
You need to apply a lot of pressure to make sedimentary crayon-rocks. To keep up the pace (especially after all that weathering) I’d have ready some big books the children could put on their foil packets and then stand on.

Sources

Momma Owl’s Crayon Rocks

The Crayon Rock Cycle

All Things Beautiful’s Demonstrating the Rock Cycle

Crayon Rock Art

Artist Laura Moriarty compiles sculptures inspired by geology textbook illustrations of cut-aways of terrain. Isn’t this gorgeous?

For more fun educational projects head over to:

Hobbies and Handicrafts at Highhill Homeschool

Homeschool Review and How-To at Hammock Tracks

Collage Friday at Homegrown Learners

Weekly Wrap-Up at Weird Unsocialized Homeschoolers

Science Sunday at Adventures in Mommydom

Fun With Magnets

February 22, 2013Sciencegrade 2, grade 3, magnetsLucinda

Magnet project fun homeschool science

This week we spent one whole morning (plus a bit of the afternoon) exploring magnets.

We started out by reading a chapter of The Magic School Bus: Amazing Magnetism.

I was delighted to find that the story is structured around a competition, the prize for which is a pizza party – this was a book that was going to appeal to at least two of J(7)’s passions! We read chapters in between doing our own experiments, which kept J nicely engaged.

Making a Magnet

We stroked a magnet along a needle in the same direction about twelve times to create a temporary magnet.

A magnet is made up of many tiny mini-magnets, or “domains”, which all line up and point the same way. Any metal that sticks to a magnet also has domains. These are jumbled up – but a magnet can make them line up, and the metal temporarily becomes a magnet.

When we dropped our needle magnet on the table a few times, the domains became jumbled again and the needle was no longer magnetic. Heat also jumbles the domains.

Magnetic Fields

One of the books we used, Magnet Science, comes with a sealed transparent box of iron filings. We observed the patterns the iron filings made when we applied different shaped magnets. The patterns showed us each magnet’s invisible magnetic field lines.

Magnet project fun homeschool science - glass .JPG — Paperclip challenge

Paperclip Challenge

I gave each child a glass of water with a paperclip at the bottom and challenged them to remove the paperclip without putting their hand in the water. Straight away they dipped the magnet into the water, so I had to add “… and without getting the magnet wet”, at which point they figured it out!

“Floating” Magnet

We used the fact that magnets with the same poles repel each other to create a cool illusion. We forced two repelling magnets together with a couple of pencils in between, and taped the magnets together. On removing the pencils, magnetic force keeps the top magnet hovering in mid-air!

Measuring Magnetic Force

We placed a paperclip at the zero end of a ruler and a magnet at the other end. Then we slowly moved the magnet towards the clip and recorded the distance in centimetres between the two at the point when the clip jumped onto the magnet. We tried this with different magnets to compare their strengths.

Measuring magnets homeschool science project collage — Measuring magnetic force

Magnetic Force and Gravity

This time we taped the zero end of the ruler perpendicular to the table and repeated the measuring process. We noted that this time the magnet had to be closer to make the clip jump, because its force is competing with another force – gravity.

Magnet project fun homeschool science - magnet compass .JPG — Magnet compass

Making a Compass

We taped a bar magnet to the base of a small plastic pot and floated the pot in a large bowl of water. After leaving the water and magnet to settle for a minute, we used a dry wipe marker to mark (on the large bowl) where the north and south poles of the magnet pointed. When we turned the magnet pot around, it returned to the same spot, its poles aligned with the Earth’s magnetic north and south.

(Happily, this confirmed our recent discovery, when we were learning about the beginning of Islam, that Mecca is in the direction of our pear tree!)

Magnet slide homeschool science project collage — Magnet marble races

Marble Races

We taped magnets to the underside of a piece of cardboard, propped it up to make a ramp, and raced metal and glass marbles down it. We used our strongest magnets and an old iPad box, but it was difficult to see whether the magnetic marble or the glass marble won the race – I think we would have seen better results with a longer ramp.

Magnet project fun homeschool science — Magnet art

Magnetic Art

We put a piece of paper on top of a magnet and made our own executive toy – paperclip sculpture. 🙂

Magnetic Rock

We looked at pictures of magnetite, a naturally magnetic rock first found at a place called Magnesia in Ancient Greece.

Resources

Books

The Magic School Bus: Amazing Magnetism gave us a story to structure our experiments around. The best experiments came from The Usborne Book of Science Activities Volume One. We also used Magnet Science (Hands-on Science), which comes with iron filings and a set of magnets.

Websites

This Squidoo lens has stacks of magnet ideas and links to resources.

Steve Spangler explains what magnets are and talks about their history. More experiments here too.

What Next?

The children’s interest in magnetite and in the causes of the Earth’s magnetic forces (not to mention Minecraft) got me thinking that this could be a good time to find out more about rocks. Watch this space!

Magnetism also relates to electricity, which C explored in a recent project. (We loved The Magic School Bus and the Electric Field Trip, which taught me a few things about electromagnetism.) We’ll come back to this topic next time we look at magnetism.

Magnet art - homeschool magnet science project — More magnet art

Do you know of any fun magnet experiments?

To see what other homeschoolers have been up to this week, check out Collage Friday at Homegrown Learners and It’s a Wrap at Hammock Tracks.

For more science posts, visit Science Sunday at Adventures in Mommydom.

Elephant’s Toothpaste – Fun With Catalysts

February 16, 2013ScienceChemistryLucinda

elephant toothpaste hydrogen peroxide homeschool science fun.jpg

“Elephant’s toothpaste” is a wonderful illustration of the power of a catalyst to speed up a reaction. It’s also very cool, and anything that shows kids how cool science is worth doing, right?

What You Need

6% Hydrogen peroxide (1/2 cup)
Yeast (1 tsp)
Hot water (2 tbsp approx) in a small dish
Food colouring
Washing-up liquid (dish soap)
Empty soda/water bottle (small)
Tray to stand the bottle on to catch the foam
Funnel (optional)

What You Do

Pour the hydrogen peroxide into the bottle
Mix the yeast into the water
Add the washing up liquid and food colouring to the hydrogen peroxide in the bottle
Add the yeast mixture to the bottle
Stand back and admire the reaction!

What Happened

The photos say it all! We had enough hydrogen peroxide in our £2.74 bottle to have two goes. Afterwards I gave the children a bowl each to mix up the red and green foam.

Elephant toothpaste hydrogen peroxide yeast

The Scientific Explanation

Hydrogen peroxide naturally breaks down over time into water and oxygen. Catalase, the enzyme in yeast, acts as a catalyst to speed up the reaction.

The washing-up liquid joins with the oxygen to make an abundance of foam. And – as with so many of our homeschool science projects – the food colouring just makes the whole thing look even cooler!

Elephant toothpaste hydrogen peroxide yeast 2

What We Might Do Differently Next Time

I get so excited doing experiments like this that there are always a few things I forget to mention to the kids. (But that’s ok because then we have an excuse to do it again. :-))

I would point out next time that during the reaction, the bottle gets warm and steam is produced from the water, because this is an exothermic (heat-producing) reaction.

I would also mention that although a catalyst speeds up a chemical reaction, it is left unchanged itself: the dissolved yeast is left in the bottle.

The Book and the Hat-Tip

Elephant toothpaste is well set-out in our favourite Science Experiments book, but I followed the instructions I found at another mum’s blog (unfortunately her blog is no longer live). Where there’s a choice, I prefer to follow a mum’s personal experience when it comes to learning fun with kids!

Do you notice our safety glasses? Not strictly necessary here, but they definitely remind us we’re Real Scientists!

For more fun science ideas, visit Science Sunday at Adventures In Mommydom.

How To Make Butter – Fun With Emulsions

February 3, 2013Sciencebutter, emulsionsLucinda

For this week’s homeschool science fun we made butter!

What You Need

Cream (we used double (thick) cream)
Clean jar with lid (not one you’ve made holes in for a previous science experiment. That was a close one!)
Tape, to secure the lid in place

What You Do

Pour the cream into the jar
Screw on the lid and tape securely in place
Shake the jar vigorously for five to ten minutes (you can pause to catch your breath)

What Happened

We shook our jars for about five minutes but nothing seemed to be happening, so we untaped the jar lid and peeked. The cream had thickened but not changed substantially.

The children were getting a bit tired of the shaking by now so I helped out and found the easiest way to keep up a rhythm was by jiggling my whole body around, ’90’s aerobics class style. Which (once they’d picked themselves up from the floor laughing) inspired C and J to launch into Gangnam Style jar-shaking – they could have carried on all day!

Eventually we heard and felt a soft, thudding sound in the jars. When we removed the lids this time, the cream had separated into a solid lump (butter) and a thin white liquid (buttermilk).

J eagerly drank the buttermilk and declared it delicious (apparently his current audiobook, Charlotte’s Web had something to do with it :-)). We spread our butter thickly on crumpets and toast – yum!

The Scientific Explanation

Cream is an emulsion that has minute droplets of fat dispersed in water. Shaking the cream makes the fat droplets stick together, forming butter.

An emulsion is a type of colloid: it has tiny particles of one substance scattered through another.

A colloid is a type of mixture: two or more substances jumbled together but not chemically combined.

What You Might Do Differently

You can start with any kind of cream or even full fat milk. Sour cream apparently makes delicious butter, too.
You can add vegetable oil or salt to vary the consistency and taste of your butter.
If you use a plastic jar you can add a (clean) marble to speed up the separation process.

Want To Find Out More?

Kitchen Science: Your Mother Was A Chemist explains in detail what colloids are, and gives lots of examples from nature. It also contains all sorts of other fascinating food science ideas.

I can’t believe I had reached the age of forty-two without knowing how easy it is to make butter!

For more inspiration, visit Adventures In Mommydom and take a look at all the wonderful science that’s been going on this week.