What it shows
Ants follow chemical trails and avoid some household substances. Counting how many ants cross a line of each substance gives a safe test of natural repellents.
The science
Ants lay scent trails to guide others to food, and they sense chemicals with their antennae. Strong smells or powders can break the trail or irritate them, so ants turn back. Different substances act on different senses, so some work better than others.
Materials
Cost: free. Many items come from home or from waste; spare parts such as LEDs, motors and wire are in the store.
- A saucer with a spoon of sugar syrup as bait
- Turmeric, chalk dust, clove powder and diluted vinegar
- A small tray or plate to place the bait
- A magnifying glass
- A timer
- A notebook
Safety
For this project: Wash hands after handling spices. Do not touch ants with fingers, and do not use sprays or strong chemicals. Release no ants indoors; do the test outdoors where ants already live.
Never use mains electricity: power models with cells, batteries or a low-voltage adapter. Sharp and hot tools, flames and lab chemicals need an adult or your teacher beside you. Keep magnets, button cells and small parts away from young children, and wash your hands after making.
All the safety rulesStep by step
8 steps. Do them in order, and test each part before you go on to the next. Write what you notice in a notebook as you go.
Place the sugar syrup on a saucer near an ant trail outdoors and wait until ants arrive.
Draw a ring around the saucer with chalk dust and count ants that cross in five minutes.
Brush the ring away, wait two minutes, then lay a turmeric ring and count again.
Repeat with clove powder and a line of diluted vinegar.
Use a fresh saucer each time so the trail scent does not carry over.
Repeat each test three times and average the counts.
Make a bar chart of average ants crossing for each barrier.
Rank the barriers from the best to the worst.
What you should see
The barrier with the lowest number of crossings is the best repellent, and the control ring with no substance shows the normal count.
Viva questions
A teacher or a judge will ask how it works. Try to answer each question before you open it, then compare.
1How do ants find food?
By following scent trails left by other ants.
2Why test three times?
It reduces the effect of chance.
3Why not use strong chemical sprays?
They are harmful to people and the environment.
4Why is the control important?
It tells you how many ants cross without a barrier.
Take it further
Test whether the repellent still works after one hour in the sun.
Change one thing, measure what happens, and add a table or chart of your readings: that is what turns a model into your own investigation.
Free ebooks for this project
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