What it shows
Tiny drops of sugar water, salt water, oil and plain water set out near an ant trail show which foods ants prefer and how a few scouts quickly bring many workers along a chemical trail. Rubbing a finger across the trail breaks it and the ants lose their way for a while.
The science
Ants live in colonies where scouts search for food. A scout that finds food lays a scent trail (pheromone) on the way home, and other workers follow it, adding their own scent, so a good food source quickly gets a busy trail. Sweet foods give the most energy, so sugar is usually chosen first. Wiping the trail removes the scent, which is why the ants wander until a new trail is laid.
Materials
Cost: free. Many items come from home or from waste; spare parts such as LEDs, motors and wire are in the store.
- 4 bottle caps or a plastic lid divided with a marker
- Sugar, salt, cooking oil and water
- A dropper or a spoon
- A magnifying glass
- A notebook and a watch
Safety
For this project: Watch only; never squash, trap or pour anything on the ants. Keep away from red ants that bite and from nests. Wash hands afterwards.
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.
Find a place outdoors where ants are already walking, such as a garden path or near a wall.
Fill the four caps with a few drops each of sugar water, salt water, oil and plain water, and place them 10 cm from the trail.
Note the time and count how many ants are at each cap every 5 minutes for half an hour.
Use the magnifying glass to watch how ants touch each other with their antennae on meeting.
Once a trail to the sugar cap is busy, gently wipe a finger across it 20 cm away and watch what the ants do.
Time how long the ants take to find the trail again.
Repeat the food test on two more days, moving the caps around so position does not matter.
Make a bar chart of total ants per food and write what it shows.
What you should see
The sugar cap gathers dozens of ants within 20 to 30 minutes; water and salt get few or none; oil may attract a few. Breaking the trail confuses the ants for several minutes until scouts re-lay it.
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 tell each other where food is?
By laying a scent trail that other ants follow with their antennae.
2Why did the ants prefer sugar?
Sugar gives quick energy, which the colony needs most.
3What happened when the trail was wiped?
The scent was removed, so the ants lost the path until a new trail was laid.
4Are ants social animals?
Yes, they live in colonies with a queen, workers and soldiers that share work.
Take it further
Test whether ants prefer sugar water to honey or jaggery water, or whether they follow a trail drawn in chalk differently.
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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