Make an on-the-ground bar chart with real Holly leaves
How many prickles on a holly leaf ?
Well that's easily answered... its about seven isn't it? With a point at the top and three spikes either side?
Holly Leaves - themes and variations
Very few plants allow you to explore variation within a species like eye colour in humans.
Make an on-the-ground bar chart with real Holly leaves showing the range of prickles on leaves. But think of the variations. One branch, one tree, height above ground, two different trees, male female trees, variegated trees, leaves collected from the ground, different localities. Transfer information or repeat onto paper chart.
- Programme of study
- Interpret tables used in everyday life; construct and interpret frequency tables (Ma4 2b)
- Draw conclusions from statistics and graphs, and recognise when information is presented in a misleading way (Ma4 2f)
- Learning objective
Children will describe variety of prickle number in holly leaves.
- Children close their eyes and imagine holding a holly leaf
- They count how many prickles on the leaf
- Explore the range of their 'in the mind' numbers
- Lay out a number line 0-30
- Explain construction of bar chart by selected chart builders
- Other children collect holly leaves, count prickles, give to chart builder
- Interpret chart
Questions to elicit knowledge and understanding
- How many leaves?
- Where did your leaves come from?
- What is the longest line?
- Most prickly leaf number?
- Least prickly leaf number?
- Where else could holly leaves be collected from?
- What shape is the graph?
- What does this graph tell us about holly leaves?
- What did you expect?
- What does this graph show us?
- Would you expect the same results elsewhere?
- More thoughts
Try saying the following with a group of children (of all ages with appropriate adaptations).
Imagine its Christmas (for those that celebrate Christmas that is) and you go into the kitchen and there on the side is a delicious looking Christmas pudding. Your just about to take a little pinch thinking no one will notice when you look to the Holly leaf that is decorating the top of the pudding. You pick up the Holly leaf (a pretend, imaginary one) by its stem. With your eyes closed you count how many prickles there are, all the way up one side to the top and down the other side, keep the number secret for a moment.
When you call out a number the children reply if it's the same… ones, twos, threes etc. A verbal barchart?
Now, if you happen to be next to a real Holly tree, then the next step is to look at real Holly leaves. They are often on the ground but even though they are prickly they aren't too tricky to pluck from the tree, carefully hold the branch then pinch a leaf from topside and bottom and pull it off towards the tree. If each child picks a leaf, counts and then finds others with the same number they can group in order. Or with even more madness, each child has a number 0-30 (or as many as there are in the class), everyone picks lots of leaves, one at a time and gives their leaves to the person with that number. Then after 10 mins or so stand back in line and leaf count each child's pile. Lots (and lots) of shouting will have to take place, maybe try a number card stuck on children (or wash off felt-tip on forehead?!)
Going a bit further…
Make a numberline zigzag book by joining and weatherproofing with tackyback squares of card each with a number 0-30 on each (in order of course). This will fold up easily and stretch 4m or so on the ground. Now, maybe having done the Xmas pud activity, choose 3 or 4 chart builders to stand on one side of the chart, the other class members must do the following. Visit a nearby Holly tree (and ask it most politely) to pluck a single leaf. Count how many prickles on that leaf return to the number line, (not crossing or disturbing the line) tell the chart builder the prickle number. They will then most carefully begin placing the leaves in a line on the ground above the appropriate number, 7s over seven, 12s over twelve etc. Two potential problems at this point are children's feet knocking the line and leaves and /or the wind blowing leaves.
Keep the children collecting one leaf at a time (swap chart builders occasionally) until the longest line is 15 or so leaves long and a 'good looking' shape has appeared.
When time is up, all the last few leaves in place, circle or horseshoe the children around the graph. Just in their heads, not out loud can they see the following? Which number on the number line has the longest line over it? What is the lowest number that has leaves over it, what is the biggest number that has leaves over it? What does this graph tell us about holly leaves that we didn't know before? Now share those thoughts.
What's the fashion for Holly this year? How do they use averages, means to describe the chart?
The shape of the graph is of course variable often with a few peculiar surprises, it might look like a New York skyline or a bell or a profile of the Mendips. A good sentence to describe the results is not always an easy one to put together.
The longest line is usual somewhere in the teens (you'll have to discover where yourselves).
Holly is fine for picking leaves from, it won't damage the tree, and it'll be all the bushier the following year.
Maybe as a follow up or as groups straight away, look at charts made by considering the following, leaves from the ground only, (even evergreen leaves drop off, a few years for Holly), leaves from different trees, male or female trees, holly is either male or female both have flowers but only the female has berries leaves from different heights of the tree. This may involve ladders or felling a tree.
Leaves from variegated trees (these are usually female and a bit more prickly).
Are leaves left and right handed? For example if it has 7 prickles are there 4 on one side, two on the other and always one on top?
Do small leaves have fewer prickles than bigger older ones?
The 'Hedgehog Holly' has prickles on the surface of the leaf as well. Is spikiness something to do with being evergreen ?(e.g. Mahonia) I wonder if prickle number is determined genetically or do environmental factors such as air, water and light play a part?
Why does Holly have prickles? In the New Forest, ponies graze Holly eagerly, prickles no problem, they even bite off branches, let the leaves go soft for a few days then come back and munch them. The foresters even pollard Holly as a winter food for ponies. If you look up to the top of a prickly tree you can see that leaves are generally less prickly,but why are there any prickles at all so high up? What long- necked browsers use to roam this land, is Holly found in Africa where giraffes wander? Apparently it doesn't grow well in central Europe as it is too cold and our tall trees are often a surprise to continental visitors.
As you do this activity you may notice tunnels of leaf miner caterpillars eating the inside of the leaf, and that some of these have been torn open by Blue Tits and Great Tits but that some have little round holes where the insect emerges. A smaller hole than normal shows that a parasitic wasp has got to and eaten the leaf miner, all good graphing data.
Other variations on the theme. If you have a wooden fence with upright planks, chalk a number line 0-30 along the bottom then as the kids bring a holly leaf you staple gun it to the fence over its number building the chart. A wonderful real life outdoor, interactive chart, which looks fine for a few months and can be refreshed on occasions.
A bit more standard is to not pick leaves but, at record stations, to fill in little empty charts as children return to tell their number of prickles they have just counted.
Consider fair tests, do they go for the most or least prickly, are they counting accurately, are they choosing leaves randomly, not recounting the same leaf etc. All the leaves are being picked at the height of the children so this activity will generally not show variation with height.
Slugs will not eat whole holly leaves but will if the prickles are cut off.
Holly is a poisonous plant but I would not be concerned at handling leaves or even berries if the poisonous aspect of plants is well emphasized. A berry can be held gently pinched between thumb and first finger like in a bird's beak, then the children repeat the following…
Dear Holly berry
I know you are poisonous,
My parents and teachers tell me all the time.
I would not eat you ,for that would make me sick (and make a mess on the floor).
I would never eat you not in a thousand years.
Then 3,2,1 squash the berry to spit out the slimy seeds and sniff the acrid aroma, with of course a good hand wash before any lunches get munched.
Lines of berries each touching the next make striking natural sculptures and patterns against contrasting backgrounds, or decorate a Holly leaf by sticking a berry on to each prickle, blood red drops on a crown of thorns.
If you hold a leaf by thumb and second finger at the tips of two opposite side prickles you can blow it to make it spin like a little wind mill, easier with gloves as the prickles drill a bit into fingers.
Holly has wonderful folktale connections, the Holly and the Ivy, Holly boys and Iy girls, life in the deep dark of winter, Holy Holly and a crown of thorns, but that's another story for you to discover.
I wonder if your homemade Christmas cards will still have the same number of prickles drawn on their Holly leaves as they use to?