Following on from last week’s work on making toothpaste, this week our STEM Club members were investigating the effectiveness of different toothpaste brands. Each group had samples of Colgate, Aquafresh and Tesco’s own brand toothpaste and had to mark them out of ten for appearance, smell and effectiveness at removing stains. The pupils used the same procedure as last week to test effectiveness. They had a tile with permanent marker on and also black shoe polish. They scrubbed the stains with toothbrushes. We made this a fair test by using the same tiles and toothbrushes and the same amount of shoe polish and marker pen. The pupils also scrubbed at the stains for the same amount of time and did their best to keep the force applied the same each time too. They used a sample of each toothpaste to see which brand performed best in stain removal. Overall both groups decided that Aquafresh amassed the most points across all three categories. The pupils have now completed two out of the eight tasks that they need to do in order to qualify for the Crest Awards certificate and badge for participation in STEM activities.
We then discussed how the Aquafresh toothpaste’s red and blue stripes come out of the tube so uniformly without mixing into the white toothpaste. We thought that this might have something to do with the tube’s internal design so we cut it open to have a look. Unfortunately this didn’t answer our question as the tube turned out to be just a regular tube. We also looked on Youtube to see if there were any videos that could shed some light on our question but to no avail. I have tweeted Aquafresh asking them how this is achieved, so if I receive a response I will post it on the STEM Blog.
