Spooky Lava Lamps

Lava lamps are one my favourite things to make, they are so easy, but really impressive for children to watch.

You will need

  • A clear plastic bottle or jar
  • A bottle of vegetable oil
  • Water
  • Alka Seltzer
  • Food colouring (a spooky colour )

Method

Fill the bottle or jar  a quarter full with water. Top up to the (near) top with the vegetable oil! They should separate into two layers, water at the bottom and oil sitting on top. Add about 6-8 drops of food colouring once they have separated. The colour will mix with the water at the bottom. Pop in half an alka seltzer tablet and watch the bubbles form. Add more alka seltzer bit by bit to keep the bubbles rising and falling.

 

Whatever you do, do NOT shake them up like my 2 year old did. Lets just say it was very messy!

Halloween Science

The Science bit

Firstly water and oil will not mix – this is because we say that water is a polar molecule – it’s structure means that is has a positive charge one end and a negative charge the other. Water molecules stick together because the positive end of one water molecule is attracted to the negative end of another.Oil molecule structure is different – it is non polar meaning that its charge is more evenly spread out, so the oil is not attracted to water – in fact we call it hydrophobic (water fearing) so it tries to get as far away from water as possible and will not mix. The reason that oil rests on top of the water rather than underneath is because it has a different density to water.

As the alka seltzer is added (this is made of citric acid and sodium bicarbonate) it reacts with the water and form carbon dioxide gas and Sodium citrate. It is the carbon dioxide bubbles that carry the coloured water to the top.

There are 27 comments

  1. Joanna

    Is there a way to print out how to make the lava lamps? Its a great idea but I can’t have 20 kids around one computer to find out how to do this.
    Thanks.

  2. Emma

    I have just discovered this site and it’s great. My daughter aged 4 is just getting into science and I was thinking about buying her a science kit but now I think I can use these ideas instead!

  3. T Lake

    Great idea!
    With plastic, would you have to leave the cap off or just make sure it’s screwed on really tight? Don’t want it exploding in the faces of my class!
    Also, would it work with dissolvable asprin as I am out of Alka Seltzer and not sure I can make it to the shop in time….
    Thanks!

      1. ZARI

        This is a great activity for the end of the year after CRCT testing. I will be doing this with my class. Thank You so Much.

  4. Halloween fun and educational » Direct To Schools

    […] DIY Creepy Lava Lamp: Teach your students about polar molecules with this great, ghoulish activity. It’s easy and has a big “wow” factor. Fill a jar one quarter the way full with water and top off with vegetable oil.  Next, squirt in some food coloring and drop in an Alka-Seltzer tablet to form citric acid and sodium bicarbonate. Then, watch the carbon dioxide bubbles carry the creepy blood red bubbles to the top! Read the full directions! […]

  5. Spooky Science Ideas | Mazzocchi ESL

    […] DIY Creepy Lava Lamp: Teach your students about polar molecules with this great, ghoulish activity. It’s easy and has a big “wow” factor. Fill a jar one quarter the way full with water and top off with vegetable oil.  Next, squirt in some food coloring and drop in an Alka-Seltzer tablet to form citric acid and sodium bicarbonate. Then, watch the carbon dioxide bubbles carry the creepy blood red bubbles to the top! Read the full directions! […]

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