Please see below what we’ve been up to at our first two Science Club sessions. These are for KS2 children – I will arrange a club for KS1 children in the future.
Dr. Roberts
25/2/25 – week 1 (‘Magic milk’)
In our first session, we looked at ‘magic milk’ where food colouring is dropped into a shallow plate of milk then washing-up liquid is dabbed into the spots of food colouring using a cotton bud. This causes movement and bursts and swirls of colour which amazed the children!
We wanted to investigate what was causing this so discussed what variables we could change. Children then decided one variable that they were going to investigate in their group – type of milk (whole, semi-skimmed, skimmed), type of washing-up liquid (Fairy or Tesco) or type of liquid (milk or water).
Children measured out the same volume of milk for their investigations using a measuring cylinder and completed their investigation.
Each group shared their findings and we talked about what they had observed and what might explain their observations. We discovered that the fat content of milk produced different results – and that water behaved differently to milk because it contains no fat. The higher the fat content of the milk, the more dramatic the effects of the colour bursts as the washing-up liquid rapidly disperses the fat. We discussed how washing-up liquid is designed to break down fat on your dishes to make them easier to clean which would explain this behaviour in milk. We talked about improvements in our investigations and what we would do differently if we repeated this activity.
Everyone enjoyed it and came up with some excellent scientific theories!
4/3/25 – week 2 (‘Fizz balloons’)
This week, children were presented with the challenge of how they could blow up a balloon without blowing air into it! After some head-scratching and discussion, we worked out that we could use baking soda and white vinegar which would react together to form a gas (which we discovered was carbon dioxide). After watching a video, we found out that baking soda is a base and vinegar is an acid – bases and acids react together to give off a gas.
Children decided one variable that they were going to investigate in their group to understand how it affected how well the balloon was blown up – amount of baking soda; amount of vinegar; type of liquid reacting with the baking soda (white vinegar, lemon juice (also acidic) or water); size of bottle; type of balloon (round or long).
Children used a measuring cylinder to accurately measure the volume of liquid and measuring spoons for the baking soda.
Children completed their investigations then shared their findings – we talked about what they had observed and what might explain their observations. We discovered that vinegar and lemon juice both reacted with baking soda to produce gas that filled the balloon, however, water did not react at all (no gas was produced). The reaction with lemon juice caused more fizzing which bubbled up into the balloon – could lemon juice be a stronger acid than vinegar? We will investigate this further another day. When more baking soda was used, there was more fizzing but it did not make a massive difference to filling the balloon with gas – maybe it ran out of vinegar to react with? Using a bigger bottle made the balloon inflate less – the carbon dioxide filled the greater space in the bottle rather than being forced into the balloon. Longer balloons were harder to inflate than round balloons – we agreed that this is also true when you try to blow them up; it is harder to force air into a long balloon.
We talked about what we would do like to investigate further – is lemon juice a stronger acid than vinegar? Is water an acid?
Another week of amazing investigating!
