School / Community-based Workshops

Workshop Description

Students make sugar solutions of different concentrations and colour them using food colouring.  They then use them to make a density column in a test tube, with a challenge to see how many different layers they can create.

Concepts covered

• density
• miscibility of liquids (whether they mix or form layers)
• states of matter – liquids (addressing the common misconception that all liquids are water-based)
• properties of materials – miscibility is an extension on the concept of solubility

Skills covered

• careful handling of chemicals
• planning scientific enquiries to answer questions
• recording data
• using test results to make predictions

Prior learning required
Students may have some experience of recording data in a table of results. 

Further study ideas

• Application: Can you make layers using liquids found in the kitchen (golden syrup, milk, water, vegetable oil).
• Application: Make lava lamps using vegetable oil, water and food colouring. 
• Mystery: Egg which floats in salt water but sinks in pure water – can students work out what the trick is?
• Mystery: Raisins in lemonade – why do they float and then sink again? 
• Investigation: how much washing up liquid is needed to make oil and water mix?
• Investigation: How do solids float differently in different liquids?  Does shape matter?

Workshop Description

Students investigate how the mass of sodium bicarbonate added to a citric acid solution affects the drop in temperature.  More advanced students are challenged to find the correct mass of sodium bicarbonate to get a target temperature drop.  

Concepts covered

• chemical reactions / non-reversible changes
• household chemicals
• energy changes - endothermic reactions

Skills covered

• careful handling of chemicals
• planning scientific enquiries to answer questions
• recording and processing data (inc graph drawing)
• using results to make predictions
• measuring changes in temperature
• numeracy - subtraction with numbers to 1 decimal place

Prior learning required

Students should have experience of recording data in a table of results and understand how a graph can be drawn and used to make predictions, though it is expected that some will need support drawing the graph accurately. 

Further study ideas

• Extension: Use a temperature probe attached to a computer to show how the temperature changes over time.  
• Extension: Investigate exothermic reactions in a similar way
• Extension: Investigate other common substances, such as a vitamin tablet / alka seltzer tablet / some sherbert mixed with water.

Workshop Description
Students will use UV/Vis to determine how much dye is needed to give cough sweets their colour.
They will first use serial dilution to make a set of standards and use these to plot a calibration curve.
The calibration curve will then be used to determine the amount of dye in a cough sweet.

Concepts covered

• UV/Vis
• Beer's Law
• Calibration curves
• Working with low concentrations

Practical Skills covered

• Use of UV/Vis machine
• Serial dilution
• Use of volumetric flasks and pipettes
• Plotting graphs

Prior learning required
Students should be able to draw a graph and represent small numbers in standard form.

Workshop Description
Students will use UV/Vis to determine how much dye is needed to give cough sweets their colour.
They will first use serial dilution to make a set of standards and use these to plot a calibration curve.
The calibration curve will then be used to determine the amount of dye in a cough sweet.

Concepts covered

• UV/Vis
• Beer's Law
• Calibration curves
• Working with low concentrations

Practical Skills covered

• Use of UV/Vis machine
• Serial dilution
• Use of volumetric flasks and pipettes
• Plotting graphs

Prior learning required
Students should be able to draw a graph and represent small numbers in standard form.