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Science Birthday Party Ideas -Throw Your Own.

How to throw a Science Birthday Party yourself. I’ve included links to buy most of the things I used on Amazon to make it even easier for you! (Affiliate Links*)

We had an eighth birthday in the house recently and decided on a Science Birthday Party. I looked into the cost of having it organised but the price really put me off and so I decided I would have a go myself. Eek!

A skittles experiment with a plate of skittle sweets leaking brightly coloured dye into the centre of the plate. Science Birthday Party Ideas

I’ve separated it into sections to make it easy to find what you’re looking for.

Science Birthday Party Activities

I got heaps of my ideas from the book below,  something I bought when we were home educating my daughter, a book which I would also recommend just to have on your shelf as it has so many fabulous ideas in and my children love it. 

The Usborne 365 Science activity book that I got a lot of my Science Birthday Party ideas from.

When the children came in, they were asked to make a guess on the treasure map, I had used an idea from the book above and drawn a treasure map on thin white card in pencil, tearing the paper around the edges and ‘ageing’ it with cold tea. When it was dry, I painted an X in a mix of bicarbonate of soda and water and left it to dry. (You can buy bicarb here but it’s cheaper in the sumermarket) Then near the end of the party, I put the map in a warm oven for a few minutes and the X was revealed, the kids couldn’t believe it! The winner with the closest guess got a pot of slime as a prize.

A tea stained 'treasure map' with a dark brown X marks the spot on. One of my science birthday party ideas,

We had a ‘Spy Table’ with a bowl of lemon juice, some plain white paper and paint brushes. The children could write their secret messages and then reveal them at home by ironing their pictures until the lemon juice turns brown. After the food, I swapped the table to STEM building and put out cocktail sticks and mini marshmallows, made a structure myself as an invitation to play and watched the children flock to the table to create the most incredible structures.

I also did a few demonstrations, I was actually surprised at how engaged the children were with these.


Adding food dye to milk was first. You pour milk into a large glass dish, I used something similar to this, then a few drops of different coloured food colouring and give the children a cotton bud each dipped in washing up liquid. When they put it in the milk, the dye jumps away. This wasn’t the most successful of the experiments as I think you need full fat milk and we used semi skimmed but the children still had a lot of fun!

Next up, a circle of skittles around the edge of a plate, add enough water to touch the skittles and watch the colours flow out. (See photo above). We looked at what happened if we gently swirled the plate and talked about which colour was strongest/ran first.

Separating inks was by far the most entertaining experiment that the children spent the longest on. It really is very simple, draw a line in felt tip across the corner of a piece of kitchen roll. Dip the corner in water and watch the colours run. The children loved making these pretty patterns! It amazed them to see what colours came out of black for example and they did so many trying different colours and stacking up lines.

A circle of pen on kitchen towel with purple and turquoise ink leaking out in a beautiful circular pattern around it. Separating dye experiment, a science birthday party idea.

The ‘Witches Brew’ was very popular. I stood a jam jar in a larger glass tray and added a big lug of lemon juice, a squirt of washing up liquid, food colouring and glitter. When the children were all gathered around watching, I added a big spoonful of bicarbonate of soda. Then watched as it started foaming. The kids thought it was brilliant, especially when different colourings were added and the foam changed colour!

Science Party Games

We had Science whispers with two lines and a scientific word passed along in a whisper to see which one got there first and most accurately.

Also, ‘Pass The Atom’ where children had to split into teams and begin at the starting line, with a balloon between their knees, racing to the finish line without dropping or bursting their balloon. As we had a large group we did the race as a relay. The children loved it so much! We used neon balloons like these.

Science Birthday Party Food

I made Petri Dish ‘Bacteria Samples’. I saw lots of versions of this on Pinterest but made some slight edits. I bought lidded Petri dishes like these ones and filled them with strawberry jelly, as they were cooling, I dropped skittles in which dissolved to make these white fuzzy circles, I think it would have been even better if I’d waited until the jelly was even cooler and less runny as some dissolved too much. Then I added sprinkles. Which dissolved! So top tip, wait until just before serving to add them!

Radioactive bacteria samples, or rather, strawberry jelly with sprinkles in in Petri dishes. Another science birthday party idea.

Then I used a permanent marker pen and drew a radioactive symbol on the lids. Offering the children ‘radioactive bacteria sample pots’ went down a treat and they were all waving their hands in the air and shouting for them!

Volcano Science Birthday Party Cake

Me holding the giant volcano cake with a huge indoor firework sending sparks flying into the air. One of my science birthday party ideas.

This is my proudest part of the entire party I think! I used this recipe and fab tutorial I found on The Imagination Tree website and made a couple of small edits. Of course! I decorated with orange and yellow cake angels fruity cubes that I separated from the rest of the colours, (2 packs but could have used more in hindsight), gold stars and a gold fountain gave the most incredible effect.

Science Birthday Party Party Bags

I bought black paper party bags like these and drew a large radioactive symbol on in bright yellow chalk pen with each child’s name on. This was so they could add the various things they made during the party. I also made up a big bowl of blue Oobleck (simply mix cornflour, water and food colouring until a mixture that is both runny when touched gently and solid when poked hard is formed, approx 1 part water to 1.5-2 parts corn flour), and filled these test tubes with it.

Holding test tubes full of blue Oobleck, the cornflour and water mix, another science birthday party idea.

If a Science birthday party isn’t your thing, you can also find my posts on the blog for a Unicorn Party or a Superhero Party.

*Affiliate links are links where I make a (very!) small amount of money if you click through from this blog post and buy the products.


1 Comment

  1. November 7, 2018 / 12:21 pm

    Ahh this looks amazing, well done for sorting it all out yourself! The cake is incredible! I agree, these sorts of parties can be so expensive, great idea to have a DIY one.

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