Eye View
Problem
These pictures show a tower with a pointed roof in the garden of a cottage.
The tower looks a different size in each of the pictures. I wonder why?
Discuss your thoughts and ideas with others.
What would you like to find out about these four pictures?
Getting Started
The left picture below shows a tower of three red cubes and a tower of five blue cubes.
The right picture shows a tower of three red cubes and a tower of six blue cubes.
All the cubes are exactly the same size so why do the towers look the same height in both pictures?
Student Solutions
We had nearly $50$ solutions sent in as well as several contributions to the blog. Overall there were many different ideas as to how the pictures came about.
Here are some of them;
Lisa from Le Rosey School in Switzerland wrote;
You can see the Pointed towers bigger than the other one because it's looked closer. The ones that look smaller is the ones that your seeing further. So the more you see closer the bigger you can see, same as if you look further then you can see smaller.
Oscar from St. John the Baptist School in England had a look at the other challenge that was in the hint. He sent in;
The tower of $6$ blocks looks the same size as the one with three because of the distance between them, if the two towers were together the tower of six would be taller.
Fabio from St. Pauls in Brazil sent in his idea about the importance of the angle;
At the first picture the photo was taken close to the tower and the picture was focusing into the tower so it seems as the tower taller than the house. At the second picture the photo was taken a little bit further so it seem that the house is a little bit smaller the tower. At the third picture the photo was taken a little bit further so it seem that the house is the same size as the tower. At the fourth picture the photo was taken a little bit further so it seem that the house is bigger than the tower.
Noor-Ul-Ain from Westfield Middle School sent is an alternative idea;
I think the solution to the problem eye view is:
- In every picture someone puts the pointed tower closer or in front of the house each time.
- Or they put the house further back or behind the house but on the side of the house.
- This affect makes a great illusion and tricks the mind of the person looking at the photograph.
The Maths Challenge group from St. Ainden's VC school in the UK sent in these ideas;
This made us think hard and we all had lots of different ideas! Zac and Izzy thought that the tower could be a different one i.e. different sizes in each picture OR the cottage could be different and the tower the same.
Louisa thinks the images of the tower have been taken from different positions. She thinks the cottage isn't real but is painted onto the lens of the camera so that it looks the same. Esme thinks that they are models put in different positions and photographed from different angles.
Marlo thinks the bricks used to build the tower are bigger than the bricks used to build the cottage. Luca thinks they used the same models but photographed them from different positions.
From New City School in London the following pupils sent in a variety of different ideas as to how the pictures came about,Naziat ,Jacqueline and Akhlak, Suffyan,William & Anika, Aqsa, Zainab & Oscar, Rizwan, Arif & Joe, Hilin , Jamian & Hamza, Patrick, Sascha & Eldon, Chloe, Bakhtavar & Gokul.
Thank you all of you for sharing your creative ideas with us.
Teachers' Resources
Why do this problem?
Possible approach
Encourage them to make suggestions as to what has happened to create these pictures. Explain that you're not expecting them to know necessarily straight away how to do it so give them plenty of time to work on ideas in pairs or small groups. Pupils may also be encouraged to validate their suggestions, for example by using two items of their choice to position and compare.
Just as valuable as having a go at this activity is the discussion which should then follow. Bring everyone together and invite pairs/groups to explain how they went about the problem. You may like to jot a few notes on the board so by the time everyone has contributed, there is a record of the different approaches to which subsequent discussion can refer. What are the advantages and disadvantages of each? Which approach might individuals use if they were having a go at a similar task? Why?
Key questions
Could you make something similar?
What do you think about others' ideas?
Possible extension
Possible support