AD – GIFTED | Did you know your fingerprints are made up of several skin layers twisted together, rather like a McFlurry?! So when we found out Flora’s latest Letterbox Lab science subscription box included making her own fingerprints, she was beyond excited. All the KS2 fun science experiments for kids in Letterbox Lab’s science boxes are tailored to the KS2 National Curriculum for STEM and STEAM. And they make learning outside the classroom so much fun – how could we resist getting down and dirty with soot and slime in Top Secret* this time?
Letterbox Lab
For those who haven’t read our previous reviews, Letterbox Lab is a series of 12 linked science kits with full instructions and tools (you only need to add water for some of the experiments). Online resources and videos accompany every box, plus some suggestions for further fun science experiments and extension activities. The Explore box (for age 6+) and the Investigate box (for age 8+) both support the UK primary school curricula, and one off boxes start at £11.00 including P&P. And it’s a very flexible subscription that you can pause or cancel at any time.
Top Secret
Top Secret is the eleventh in the Investigate box series, and is all about using science to reveal secrets. There are six different fun science activities, plus the usual Messiness star rating at the beginning of each one. The box looks at chemical reactions, thermochromism, fingerprints, colour filters, polarised light, and reflections, including building a periscope. So, how did we get on?
- Tea Light my Fire – tea light, food colouring, some water, a plate, a glass.
- See Heat – colour changing putty (slime).
- Reactive Writing – 1 x sodium carbonate, 1 x iron sulphate, 1 x copper sulphate, 1 x potassium hexacyanoferrate, cotton buds, cotton pads, paper, tweezers, safety gloves, label template, the test tube rack and 4 x test tubes from Box 3, a tray, safety goggles and scissors from Box 1.
- Forensic Fingers – balloon, tea light, fingerprint record card, some water, a heatproof plate.
- The Third Dimension – 3D glasses, polarising filter, lolly stick, sticky back foam, frame template, scissors, mobile phone, some clear plastic objects (eg, test tubes).
- Picoscope – 2 x mirrors, 12 x glue dots, scissors, pencil, the box.
- A 24-page instruction booklet, a safety sheet, and a Secret Re-Agent badge.
Tea Light my Fire
Flora had to add the food colouring to some water and then pour it onto a plate. Next, she put a tea light on the plate and lit it (she’s 11 but if your kids are younger you may want to do that). Then she placed a glass upside down on the tea light, and sat back to watch. What do you think happened?
Fire needs oxygen (a gas) to burn, so when it’s used up all the oxygen in the glass, it goes out. But why does the water get sucked up the inside of the glass? Well, it’s because the pressure has dropped and there are two hypotheses for this. One, the missing gas is the oxygen so the water should start getting sucked up before the flame goes out. Two, the flame heats up the air, making it expand and escape out of the glass, so when the flame goes out, the air cools and takes up less space, and the water gets sucked up. So, which is it? Watch again.
Is hypothesis one or two most likely to be true? Or, could they both be true? And were you right? 🙂
See Heat
Slime is great, but when it changes colour because of heat then it’s even better… This experiment was all about thermochromism (thermo = heat, chromism = changing colour). Remember our photochromism experiment with the beads and UV light back in Box 5? This is the same but with heat. Watch what happens when Flora sandwiched the flattened slime between her warm hands for a few seconds.
And then what happens when she placed something really cold on the slime. (Yes, that is a novelty submarine ice cube, thank you for asking).
Heat is a kind of energy and when something is hot, the tiny atoms shake fast and bump into other atoms, making them shake as well. This experiment was also about testing to discover which materials were the best conductors of heat.
Reactive Writing
We roped in one of Flora’s Y6 school friends for this next fun science experiment, testing a series of chemicals to find out which combination of reactions made the best formula for writing secret messages.
They had to dip a cotton bud into one chemical, write with it, and then dip a piece of cotton pad into another chemical and wipe it over the top. With 12 chemical combinations to try, it took a little while, but it was great fun seeing what worked and what didn’t. Here’s the winning formula, writing with iron sulphate and wiping over with potassium hexacyanoferrate. A far cry from my writing with lemon juice and holding over a light bulb days…
Forensic Fingers
If you’d told me you could hold a balloon in a flame without it exploding, I wouldn’t have believed you. But it turns out you can. Flora filled a balloon with water, about half the size of a normal balloon and then lit her tea light on the plate. Rather tentatively she lowered the balloon into the flame for a couple of minutes, to enable a build up of soot. For those of you wondering why the balloon didn’t explode, it’s because the cold water absorbs the heat, so the rubber never heats up enough to break. Phew.
It did take quite a while to build up enough soot for each finger (around ten minutes overall) but then she could roll her fingers in it for her own personal, unique fingerprint record card. Fun fact: remember that McFlurry analogy? The ridges of skin forming your fingerprints were formed before you were born, when your skin layers were growing at different speeds and squashed each other. And that’s why everyone in the world has unique fingerprints, even identical twins. Truly a secret message, especially at crime scenes 🙂
The Third Dimension
Remember the rainbow spinner back in Box 1, Marvellous Mixtures? White light is made up from all the different colours of the rainbow. Flora used the 3D glasses to see how colour changes when colour filters (red and blue) only allow certain colours pass through. When she covered the blue lens, the red dot turned dark blue and the red dot turned yellow. And when she covered the red lens, the blue dot turned grey and the red dot turned dark brown. In the real world, everything is in 3D but we see flat images in 2D.
When light hits our retinas, our brains put the 2D images from each eye together to create a world with depth. The 3D glasses block coloured light from reaching each eye so even when the images are flat, like the blue and red The Third Dimension title in the booklet, you see the illusion of depth. Taking this further, do you remember the fad some years ago for wearing 3D glasses in the cinema? Well, cinemas use polarised light and to demonstrate this in action, Flora had to make her own polarising filter. And look what happens when you view an LCD phone screen through the polarising filter…
Light travels in wobbly waves in all directions. But polarised light wobbles in one direction and our filter removes all light that travels in any other directions. Light from an LCD phone screen is polarised so if the light from here doesn’t match the filter, it gets blocked and the screen should look black (which is how 3D films work, to block different images). However… plastic changes the polarisation of light and affects different colours differently. And because Flora has a plastic screen guard on her phone, that’s why you see this beautiful rainbow effect in the picture 🙂
Picoscope
Time for the last of our fun science experiments to discover how light bounces by turning our box into a periscope. Flora had to cut two flaps in two specific places on her box and stick the mirrors onto each flap. Confession time: we used some heavy duty scissors for this, as the smaller ones from Box 1 couldn’t cope with the cardboard.
And then, when you look through the bottom of the periscope, you can see an image from much higher up – a plant on top of our piano in this case. (Apologies, this was quite hard to demonstrate in a photo). Basically, when light hits a shiny thing, it bounces in a specific way and at a specific angle, so you can see what’s reflected in the top mirror, even if there’s something else in the way, such as a piano. Or several metres of water in the case of a submarine. And if you tilt the periscope on its side, we discovered you can even see around corners 🙂
Final thoughts on these fun science experiments
This time we carried out all the experiments in two separate sessions, to spread out the fun, although I’m sure you could easily do them all in one day. Flora’s favourite fun science experiments were Tea Light my Fire and Reactive Writing – although she’s still having fun with the putty slime from See Heat too! Big thank you again to Letterbox Lab for our eleventh Investigate box, we loved it. And even though our next box will be our last one, which is truly very sad, Flora and I can’t wait to discover how science has made the world a better place with Go Forth and Science in Box 12.
Did you enjoy learning more about fingerprints, polarised light, and secret messaging? Which experiment is your favourite? Do you know any kids who’d love to try Top Secret – or discover more about science in general – with one of these amazing subscription boxes?
* This post features gifted items but all opinions are our own (please see my Disclaimer).
My niece would certainly love this one. She loves slime! 😀
I don’t think there’s a kid alive who doesn’t!
Ohh this looks so fun! My daughter is still too young to do anything like this, but I really hope she likes it when she’s older. I bet I’d learn all sorts! This is such a good service.
Claire.X
http://www.clairemac.co.uk
They are such fun, honestly – and yes, I’ve learned masses as well as Flora! x
Forget about ages 6+ and 8+ I had just as much fun reading this!
And what child doesn’t like slime?
Ha, that’s great to hear, and yes, I agree!
Love this! Such a fab way to get kids to have fun with science at home for sure – and dare I say fun for us adults too? I think I’ll be forwarding this post to my cousin for her kids for sure!
Oh yes, it’s not just Flora who loves these boxes, I do too. I learn so much and they’re such fun to do – especially when they hark back to previous boxes, and remind us of what we learned before. Highly recommended for all kids! x
Oooh how much fun does this box sound! Tea Light My Fire (GREAT PUN) was really interesting and I didn’t expect the water to get sucked up the inside of the glass. The secret messages is cool too – you’d better keep an eye on her after that one though… just in case! xxx
It was SO much fun! And yes, I know, I will be keeping a close eye on our lemons, because she knows what to do with them now, haha! xxx
After the gardening post, I truly love the one with science experiments! It looks like this box was lot of fun and honestly would love to try it too even if I don’t have kids. the experiment with the balloon and reactive writing sound amazing! x
I think if we didn’t have Flora, I’d probably buy these for Alan – who says big kids can’t have fun like this too?! x
Is it bad that I want to try all of these? I am no kid (technically, on paper at the very least!) and I am not much of a science person, but these look too good to pass on! Give me something where I can learn from while playing with little glass jars and bits and I will be a happy girl indeed x
Not at all, I’m lucky we have Flora so I have the perfect excuse, but I can hand on heart confirm how much fun they are for me too! x
oh wow this is awesome. I’d have loved this when I was a kid. The balloon finger print bit is wicked
Rosie
It’s so much fun – and not too messy either, win, win!
I love this post, and it’s always so fun to see the experiments you help your children with- they sound like a lot of fun! I think learning more about finger prints is particularly interesting x
I had no idea the complexity of fingerprints, it was quite eye opening! x
I love to see children performing science experiments which I must say take me back to my own youth! These kits provide great value and not only educate, but provide an experience your children will likely always remember. Thanks for sharing!
Yes, exactly, Jodie! I don’t think you can put a price on treasured childhood memories but these are certainly great value 🙂
How fascinating. I thought the balloon would explode too. I feel the need to try it too. :)) These experiments are so interesting, I just love this subscription box, it’s amazing for children.
I know, we couldn’t believe it didn’t! We love our boxes so much, I can’t believe the next one will be our last 🙁
Hi Lisa,
How absolutely … AWESOME!
These kits are fantastic – learning is so much more enjoyable when it’s fun like this. And thank you for the videos and pictures – excellent additions to the narrative. Almost makes me wish that I was a kid again. Almost.
Hi Richie – I know, they are fabulous, we absolutely love them! Thank you – the videos do give a little flavour of the boxes, don’t they? And these aren’t just for school kids, us big kids love them to0 🙂
This looks and sounds so fun! I really can’t wait to have kids just so I can do cool things like these with them. Thanks for sharing! xo
xoxo Olivia | http://www.oliviaandbeauty.com/
They are so much fun – such a great idea! x
How I feel ya on the tension I feel about balloons popping . . . something about the unexpectedness of the bang always makes me jump.
Loving the looks of the reactive writing! I used to fancy writing in invisible ink too, though I tried the lemon juice scenario with very poor and acidic results. 🤣
Fingerprints are a constant fascination to me. That they still remain so unique to each individual is both food for thought and science.
Thanks for sharing another fun-filled adventure!
Haha, we were on tenterhooks, kept waiting for the big bang! Yes, we were so curious about the fingerprints, and finding out how they are created was just fascinating – another great box, thank you, Letterbox Lab!
These do look like so much fun! A great way to learn at home and spark an interest in science 🙂
Absolutely – perfect for lockdown and homeschool too!
I love all these ideas. When I was younger my mother would do little experiments with me and I loved it. Such good memories.
Fun childhood memories are so precious, aren’t they? 🙂
I think it’s time to take the plunge and try letterbox lab. I think I want to do it more than my nephew!
That is freaking fascinating about finger prints.
Cora | https://www.teapartyprincess.co.uk/
Do it, do it, you won’t regret it and you’ll be the coolest auntie ever!
The tea light is super cool 😍😍😍 I would to try this as a kid
Thanks for sharing
Books to read once in life 📖
https://uncuaderno4cero.wordpress.com/
It really is – I think most kids would love to!
This is an interesting activity for kids to do with their parents. Your daughter must be a genius because of these activities. Keep it up!
Ha, we think she is too, thank you, Fadima! x
This looks like so much fun! I love doing science experiments! Unfortunately my son is still a little too young for this, but I definitely have to remember it for when he is a little older. Thanks for sharing!
They are so much fun – I’m sure your son would love the Explore boxes when he’s a little older!
Great post! It’s really good that these activities are fun and educational! Loved how you’ve shown us the results of the experiments! I remember doing some of these experiments in school and they were really cool! Thanks for sharing this!
They brought back memories for me too 🙂 Glad you enjoyed the review!
These look like fun science experiments for kids at home, I’d want to try them myself! x
Lucy | http://www.lucymary.co.uk
And that’s why I’m lucky to have Flora, haha! x
I love that you found a way to make learning so much fun. Thank you for sharing this!
You’re welcome, glad you enjoyed the post!
This box is fun! It is really a cool way to learn!
xoxo
Lovely
http://www.mynameislovely.com
Indeed it is, thank you 🙂
How fun! I think I’d even love to do these as an adult. What a great way to get kids enjoying science too. Such a cool subscription idea!
I can confirm as an adult (!) they are every bit as much fun as for a kid 🙂
Wow! These are all fun ideas! I really love science experiments when I was in grade school. 😍 I’m sure my little sister will definitely enjoy the See Heat experiment. She’s literally obsessed with slime! 🤣 Thanks for sharing x
I don’t think there’s a child alive who doesn’t love slime – I’m sure your little sister would love these boxes too! x
Ooooh wow, these are amazing! I love the idea of the Letterbox Lab subscription and they have some super creative things to do in this one. I love the writing and the fingerprints especially. Great for kids and us grown up kids alike! x
Absolutely, these boxes are perfect for kids of all ages and sizes 🙂 x
what a fun kit! It’s so good they are offering more of these kits for kids! When I was growing up, there were barely any on the market!
I know, I’m so sad these weren’t around when I was Flora’s age!
This is the first subscription box I’ve heard of this kind and I can understand why it was a success with your kids. All these experiments/activities look like so much fun! I’m always on the lookout for easy activities to do with my Girl Guide unit and the tea light on the water one is both fun to do and informative.
Thank you for sharing!
Thank you, Loren, I’m so glad you enjoyed the post – I hope your Girl Guides like the experiments if you re-create them too!
Thanks for sharing, this box looks interesting for investigating science, my nphews had a spy set once with invisable ink 🙂
Invisible ink – that takes me back, wow! Glad you enjoyed the post 🙂
Oh, what a great box to come through the door! I would have loved something like this when I was younger (maybe even know haha!) My niece would love this!
Thanks for sharing 🙂
Aimsy xoxo
Aimsy’s Antics
I know, I’m so sad they weren’t around when I was Flora’s age!
Oh this sounds so fun! Can’t wait until J is a little older and can enjoy stuff like this too. There’s so much great stuff for kids now xx
There really is, I wish they’d been around when I was Flora’s age, I’m sure I’d have enjoyed science a lot more! xx