1st Class Science – Cleaning Coins!

First Class completed their first science experiment following the steps of the Scientific Method.

Scientific Method:

  1. Question
  2. Prediction
  3. Resources /Materials/ Equipment
  4. Steps / Method
  5. Results / Data
  6. Conclusion / Summary

The question we wanted to explore was “What cleans old coins the best?” We had a selection of liquids to experiment with: water, washing up liquid, vinegar and Cola.

Before conducting the experiment we first made our predictions. Everyone voted for one liquid, and we recorded our responses as a block graph. 3 people voted for water, 5 voted for Washing up liquid, no-one voted for vinegar and 8 voted for Cola.

Materials: The equipment that we needed included:

  • a jug of water, bottle of washing up liquid, bottle of vinegar and a bottle of Cola.
  • 4 glasses, the same size
  • coins, all the same size and material (we used 1c coins.)
  • a sand timer

Steps: Next we conducted our experiment using these simple steps.

  1. Pour water, washing-up liquid, vinegar and cola into one each of the 4 glasses. Fill each glass to the same height.
  2. Place some coins into each glass. Use the same size coins.
  3. After 15 minutes take the coins out of the glass.

Data: When we took our coins out after 15 minutes, we discovered that the water and the washing up liquid didn’t really clean the coins at all. However, the vinegar did a really good job – the colour of the coin was really shiny. The cola also did a good job.

Conclusion: We found that the vinegar did the best job of cleaning the coins. No-one predicted this. This is because the vinegar contains an acid which helps to dissolve the dirt. Cola also contains this acid, but not as much.

We know that our dentists don’t like children drinking cola. As a final observation, we decided to leave some coins in a glass of Cola overnight for 24 hours. After 24 hours the coins were so shiny! This was the acid working on the coins. This same acid is really bad for our teeth.

(The coin in the centre has not been cleaned. The 4 outside coins were left in Cola for 24 hours. Look at the difference!)

We had a great time experimenting!

Post Author: Linda Phelan