Today is the start of Chocolate week in the UK. This event celebrates the country’s favourite sweet treat with a host of cocoa-filled happenings around the country. And what a great excuse opportunity for some science lessons using chocolate.
Here are a few suggestions of lesson ideas:
Which type of chocolate has the lowest melting point?
In this enquiry lesson students are given squares of chocolate – two each of different brands of milk, dark and white and asked to plan and carry out an investigation into which has the lowest melting point. Lots of scope for looking at fair testing and how to gather accurate and reliable evidence. Can be used with KS3-4 students.
For KS2 why not let the students explore changes of state by making chocolate leaves? Melt chocolate and paint this liquid onto leaves (rose are good). Then when cooled carefully peel off the leaves to leave solid chocolate leaves. The children can describe the changes they see during each part of the process.
Chocolate – healthy or unhealthy?
This is an idea for a class debate and helps students to develop research skills. Divide the class up into two groups. One group will be arguing that chocolate is unhealthy (leads to tooth decay, obesity etc) and the other will argue that eating it has health benefits (such as contains antioxidants, prevents heart disease). The students can use the internet for research and come up with their arguments before taking part in a class debate.
Can chocolate effect sports performance?
The weblink below shows a clip from a TV programme where chocolate was tested to see if it improved the performance of people during exercise. This could be shown to students as an example of a clinical trial or students could be asked to plan a similar experiment. You could also try out a similar experiment within the class with half the students being given a high cocoa percentage chocolate and the other a placebo of a low cocoa content chocolate and then doing some fitness tests. The students could gather the data and analyse it.
I devised a similar idea but I told the students that the chocolate they were testing was a new type called ‘BrainChoc’ which claimed to improve short-term memory. This BrainChoc PowerPoint contains resources for this lesson idea.
Measuring the speed of light using chocolate
By putting a bar of chocolate in a microwave and measuring the distance between the melted spots you can work out the wavelength of the microwaves. Using this and the frequency (which is written on the back of the machine) students can use the wave equation to calculate the speed of microwaves which is the same as light. This is a great experiment and it works! I’ve tried it using grated cheese but using chocolate sounds much more tasty.
Those are my ideas – can you do any better? Please share your ideas for chocolate-based science lessons by adding a comment below.
The chocolate week website. Click on ‘About chocolate’ for information on how it is produced.
Information useful for the debate idea.
Scroll down to find the ‘hot chocolate’ experiment which gives further details about how to measure the speed of light using chocolate.
Video clip showing clinical trial