Tag Archives: Biology

Enzyme Science Fun – Inflate a Balloon With Liver & Hydrogen Peroxide

liver and hydrogen peroxide enzyme experiment

Last week Cordie thought up a fun  liver and hydrogen peroxide enzyme experiment. The idea is an interesting extension of elephant toothpaste. And it extends the chemistry learning into biology (useful for homeschool records).

When we make elephant toothpaste we use yeast as a catalyst in the breakdown of hydrogen peroxide into water and oxygen gas. By adding soap and food dye, we get oodles of colourful foam that make for a fun and memorable science lesson.

Cordie recently discovered that liver also contains a catalyst which breaks down hydrogen peroxide. She decided to try to inflate a balloon with the gas produced and to test it for oxygen.  (Is it just my kids that love experiments where they get to play with fire?)

You can watch Cordie demonstrating her experiment in the video [4:39] below (with crumpet cameo from Jasper).

What you need

Liver (we used about 200g)

Hydrogen peroxide (we used about 75ml / 1/3 cup of 9% / 30 vol)


Small plastic water bottle


Peg or clip


If you want to test for oxygen you’ll also need:

Splint (thin piece of wood)


What you do

1. Chop the liver and put it into the bottle

2. Pour the hydrogen peroxide into the balloon via the funnel

3. Carefully put the neck of the balloon over the bottle so that the hydrogen peroxide pours onto the liver

4. Hold the balloon in place as it inflates with gas, then clip it closed

5. If you want to test the gas, light the splint then extinguish the flame. Immediately insert the still-glowing splint into the bottle


What happens

As soon as the hydrogen peroxide touches the liver, foam appears and the bottle gets warm. After a few seconds the balloon begins to inflate.

When you lower the glowing splint into the bottle, the flame rekindles. (My kids’ favourite bit!) There should be enough oxygen to do this over and over again.

What’s happening?

Just as with elephant toothpaste, the hydrogen peroxide is broken down into water and oxygen in the presence of a catalyst. (A catalyst speeds up chemical reactions without being changed itself.) The reaction is exothermic – it produces heat.

2H2O2 —-> 2H2O + O2


Liver contains a biological catalyst, the enzyme catalase.

Just as the liver in our experiment breaks down a poisonous chemical into harmless substances, an animal’s liver breaks down toxins and renders them harmless.

Take it further

Heat and cold affect how enzymes work.  In Cordie’s science class she timed her experiments using boiled and frozen liver alongside liver at room temperature.

Further resources

BBC Bitesize – Webpage and video about liver, hydrogen peroxide and enzymes

How to make elephant toothpaste

* * *

Do let me know if you try this. I love hearing from you. 🙂

If you liked this experiment I’d love you to share it on Facebook or Pinterest. For more about how we homeschool, subscribe to my YouTube channel or like Navigating By Joy on Facebook.


I’m appreciatively linking up with Weird Unsocialized Homeschoolers.


We’re really enjoying learning about the human body as part of our REAL Science Odyssey Life (level 1) curriculum.  The combination of the hands-on activities in the curriculum, great living books and the wonderful resources available on YouTube really brings the human body to life (ha ha!).

Today we found out about blood. We made a model of blood using half a cup of vegetable oil (for plasma), half a cup of red kidney beans (red blood cells), five butter beans (white blood cells) and a tablespoon of dried lentils (platelets).

All stirred up in a jar this was a great way of learning how, although blood looks like a homogenous red liquid, it is actually made up of several different components, appearing red because of the red blood cells.  We talked about what each component does.

The children coloured and labelled diagrams of the blood model, and we read The Magic School Bus Has A Heart (highly recommend – we love the Magic School Bus!). We also looked at Blood!  which is a nicely illustrated and very comprehensive early-reader style reference  book but was less of a hit in this living-books-loving house. Usborne’s flap book See Inside Your  Body has some great pictures of the circulatory system.

Finally we enjoyed our favourite new find – the “Once upon a time… Life” series on YouTube. These are short animated movies (15-30 minutes) by Procidis which C and J absolutely LOVE.  Each mini-movie (viewable in 3 parts on YouTube) covers a different topic using cartoon characters inside the body.  The science is spot on and very detailed, but presented in such an engaging way as not to overwhelm younger children.  This morning we watched the movie about the blood and another about the heart.  [Edit: C and J later begged me for another, so now they know all about platelets, too!]

Science And Eggs

When I tell people we homeschool, people sometimes ask about how I plan to do science as the children get older.  For some reason it’s the one subject they can’t imagine happening at home.

Well, my experience so far is there is a wealth of resources out there – books of fun experiments, great websites, inspiring blog memes like Science Sunday, plus of course the usual wonderful selection of homeschool blog posts.  In fact science is possibly the easiest subject to find ideas for. All these, together with a few living books and the children’s innate curiosity, would almost certainly be enough to give primary aged children a great start in science.

Not the most interesting photo ever. But the tablecloth is nice.

Then when I read Weird, Unsocialized Homeschoolers’ review of the REAL Science Odyssey curriculum, it sounded brilliantly hands-on, plus it ticked the box of being available as a (UK-friendly) downloadable eBook, so I thought we’d give it a go.

We began the “Life” curriculum (C’s choice) before the summer break so we started this year’s science with a recap of the differences between living and non-living things.  In keeping with his new love of writing (really!) J eagerly seized and completed the chart I had half filled out back then on his behalf (him dictating what to write).  His answers to whether a rock or a bicycle moved on their own, breathed, reproduced etc were rather random but very interesting and the exercise definitely got him thinking!

Next we talked about how living things are made up of tiny cells, and looked at an egg as a rare example of a cell that’s big enough to see with our eyes.   Luckily I had half a dozen slightly-out-of-date eggs to hand because it took the children a few goes to crack their eggs without breaking the yolk!

Before we cracked the eggs we looked at them through magnifying glasses and noted the tiny holes in the shell through which air and water pass.  Then we talked about the parts of the egg and their purpose, and found the tiny white blastodisc  in the yolk and the tail-like chalaza which anchors the cell, neither of which I have ever noticed before!  We’d lost J to lego by the time it came to drawing the egg, but C enjoyed colouring and labelling hers, and I left J’s page blank – who knows when he might decide to come back to it with a wave of enthusiasm!

I don’t know how science will evolve for us if  we’re still homeschooling at senior school level – I’ve heard of people getting together in science co-ops and even using school lab facilities – but thinking back on my own school science experience, I don’t have the slightest doubt that if C and/or J are still at home, the freedom they will have to pursue their own interests at their own pace and on their own terms will definitely outweigh any shortcomings in facilities.  Besides, there’s not much you can’t get on the internet these days!

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