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Medieval Castle Hygiene Investigation

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Medieval Castle Hygiene Investigation

You are the science team investigating how hygiene conditions can affect microbial growth. Use the evidence and experimental-planning tasks below. Do not collect samples from people, toilets, rubbish, soil or other potentially harmful sources. Any microbial culture work must be teacher-supervised and follow school safety rules; sealed plates must not be opened after incubation.

The evidence

Medieval castles varied greatly, but many had limited access to clean water and no modern sewage treatment. Some had latrines built into walls, with waste dropping into a pit or moat; these systems could contaminate nearby water if poorly managed. People did wash, and soap existed, but bathing facilities and clean water were not always easy to access. Crowding, food waste and pests could make it easier for some infections to spread. Today, clean water, handwashing, sanitation and safe food handling interrupt many routes by which disease-causing microbes move. This history suggests questions to test, but it does not prove that any particular surface is contaminated.

1.Which conclusion is best supported by the evidence?

Every medieval castle had the same hygiene conditions.
Some castle conditions could increase opportunities for contamination and disease spread.
People in medieval times never washed.
A moat always made a castle’s water safe.

2.A latrine pit is close to a well used for drinking water. Describe one plausible route by which microbes could travel from waste to a person, and name one piece of evidence you would need before claiming that this happened.

Plan a fair investigation

A class wants to compare microbial growth on two types of surface: a clean, dry tabletop and a tabletop after a standardised, safe simulation of poor cleaning. Use only a teacher-approved, non-pathogenic classroom method. Keep any cultures sealed and dispose of them as directed by the teacher.

3.Write a testable research question for this comparison. Make clear what you will change and what you will measure.

4.Name the independent variable, the dependent variable, and two variables that should be kept the same.

5.Which plan would produce the fairest comparison?

Swab different-sized areas and incubate plates for different times.
Use the same-sized area, swab method and incubation conditions, changing only the cleaning condition.
Use one plate for the clean sample and several plates for the other sample.
Choose whichever result looks most convincing and ignore the rest.

6.Explain why the team should take several replicates for each condition rather than relying on one plate per condition.

7.A student suggests opening an incubated culture plate to identify the colonies by smell. What should the team do, and why?

Interpret results and apply the idea

After safe observation, a class records this fictional data. Colony counts are observations, not direct identification of species or proof that disease would occur.

Condition

Replicate counts

Mean colonies

Clean control

2, 3, 4

Cleaning simulation

8, 10, 12

8.Using the results table, calculate the mean for each condition and state which condition had the higher mean. Show your calculation or reasoning.

9.What do these fictional results suggest about the two surface conditions? Give one limitation that stops the team from making a broader claim about medieval castles or human health.

10.Choose one modern hygiene practice—handwashing, safe drinking water, food hygiene or sanitation. Explain how it can interrupt a route of disease transmission.