- Students will be able to:
- observe how dandelion seed heads release their seeds
- discover if the number of puffs needed to blow the seeds away tells the time of day.
- You will need access to an area where there are dandelion seed heads. Around the margins of a playing field is a likely place to find them.
What You Will Need:
- Clipboards and pencils to record results.
- Optional: Magnifying glasses.
The fluffy dandelion seed head is often nicknamed a 'clock'. This is because in the past children blew at the seed head and imagined they were telling the time by counting how many puffs it took to blow the seeds away. One puff means it's one o'clock, two puffs means it's two o'clock, and so on. But is this true?
Before starting, tell the children the little story behind the term 'dandelion clock' and show them an example of a dandelion seed head. Demonstrate a brief puff (not a long blow). Ask, "Do you think we can use this to tell the time?" Well let's find out.
Go outside on a warm, dry day, in time to do the testing 'on the hour', e.g. 2pm, allowing for lead in activities.
What to do
- Look at the seed heads closely and see that they are made of lots of tiny 'parachutes'.
- Allow the children one 'clock' each for them to practice their puffs on. Emphasise that for our little test to work, we all need to use the same strength of puff. It needs to be short and relatively sharp. Let them have a go, then emphasise again the idea of everyone doing the same strength of puff by practising together.
- Observe and discuss how the little parachute seeds float to the ground and how in the wind they can drift a long way.
- At 2pm, or whatever hour you choose, start the test:
- Work in pairs. For each clock, one child puffs while the other records how many puffs are needed to blow all the seeds away.
- Next they reverse their roles.
- If available, use magnifying glasses to observe dandelion seed heads in detail.
What you found
- Discuss how many times students had to puff in order to blow all the seeds from their seed head. Was this the same as the time of day? For example, if the test was done at 2pm, did it take two puffs to dislodge all the seeds?
- Were the clocks mostly correct in telling the time, or not?
- Is the idea of them being clocks 'real' or 'pretend'? (Regardless, it is fun to do!)
- Discuss the role of the seeds in starting new dandelion plants some distance from the parent plant.