Students will learn to use the calipers, virtual props, and ratio tools in the Size Wise app to create forced perspective photographs while noticing and using ratios in the process.

*Image Size Ratios*

**Intro to Topic and App** (10 minutes)

**Virtual Giraffe Challenge **(20 minutes)

**Sharing and Discussion **(10 minutes)

- Size Wise Quick Intro: Virtual Giraffe Student Sheets
- 1 iPad with Size Wise app
- Wifi access to send work to other iPads or to online project space
- Measuring tapes
- Prep: Give yourself ample space for students to move along distances. Taking turns in the hallways can work or going outside can work nicely.

**Intro:** Have you ever seen those funny photographs where things look wildly larger or smaller than they really are? Display examples like those found on the blog: www.hongkiat.com/blog/force-perspective-photos

In this activity, you will create some forced perspective photographs by taking pictures of you and your friends posing with a virtual giraffe in the Size Wise app.

The Giraffe Challenge: Pose with the giraffe in three photos so you are:

- As big as the giraffe and can tickle his chin,
- Three-fourths the size of the giraffe,
- One-third the size of the giraffe.

Which picture is the funniest? Use ratio language to describe the composition of your shots.

**Virtual Giraffe Challenge** (20 minutes):

Have students:

- Open the app, and select “Take Some Pics.”

- Create an image size caliper by tapping on “Calipers” and then tapping “Image Size Caliper”
- Measure friend with the Caliper from head to toe.
- Browse “Virtual Props” and select the giraffe.
- Start taking your photos with the Giraffe.
- Work together to take a picture with the subject appearing to be the same height as the Giraffe (1:1 ratio).
- Tap the “Ratio” tool and examine the data. Ask: What is the ratio? What does this mean?
- Take two more pictures where the subject is:
- 3/4 the size of the giraffe
- 1/2 the size of the giraffe

- Use the Ratio and Data tools to look at the data. Ask: Do you see any patterns?

Prompt students to describe the photos that they took and what they had to do to achieve certain shots. Encourage students to think about how many times larger or smaller an object is in relation to another. Have students discuss which ratios get the best or most satisfying effects (e.g., why does setting up your subject in a 1:1 ratio with the giraffe look funny)?

Ask students:

- How many times larger/smaller is one object than another?
- How would you describe this as a ratio?

Language and discourse to listen for:

- 25% the size of ________
- Three times larger than ________
- It is in a ____ to _____ ratio

Giraffes on average are 15 to 18 feet tall. You can extend this activity by having students compose a realistic shot of themselves standing next to an average height giraffe. They will need the ratio and caliper tools and real-world data about giraffe heights. If they were standing next to a real giraffe, what would the ratio of the student’s height to the giraffe’s height be? What would they look like standing next to one another? For example, if a student is 5 feet tall, a 15-foot giraffe is 3 times as tall as she is. The image size ratio of student to giraffe is 1:3. A link to other interesting “Size” issues with giraffes can be found here:

http://animals.nationalgeographic.com/animals/mammals/giraffe/

This can also be done with other virtual props with known sizes in our prop library.

Move back in forth in space to pose with a virtual giraffe so that you appear to be different heights.

- Add a new caliper with your actual height.
- Go to “Virtual Props “and choose the giraffe
- Tap the “Distance” tool as well as “Ratios ” and snap the following three pictures:

- Your image size is in a 1:1 ratio with the giraffe
- Your image size is in a 3:4 ratio with the giraffe
- Your image size is in a 1:2 with the giraffe

- In the Gallery, tap “Data” and drag in the three pictures you took and compare.

**Reflection Questions:**

- Try this challenge again with another virtual object such as the soda can, statue of liberty, etc. (NOTE: If you choose a SMALL virtual object, shoot for ratios of: 1:1, 2:1 and 4:1.) Which ratios produced the most amusing effects? The most realistic effects? Why do you think that is?

- In the Gallery, tap “Data” and look across the data of your pictures. Observe the way your image changed sizes between the photos. Think about and express the mathematical relationships you see.