What's New

A couple of things have been altered in this update:

1. The app is now available in the Dutch en German language! The app will automatically choose your device's language.
2. We've added an info-graphic that shows why the angle of the axis of the Earth changes in relation to it's plane of revolution around the Sun. For simplicity's sake we still use some interactive parts where the angle of the axis changes. This allows you to explain why seasons exist in a uncomplicated way. For older children there is the new info-graphic.

App Description

Why do we have day and night? Why is the winter cold and summer warm? Why is the moon sometimes shaped like a banana? Not so easy to explain.

But now children can find out themselves: in Jeffy’s World, a playfull serious app for children and parents.

Jeffy is a funny, but a little short tempered character that needs your help. By helping Jeffy, you discover how time, seasons and the movement of the world are interrelated.

Jeffy’s World contains:
-3D models of the world, the Sun and the Moon
-12 short animations
-interactive info graphics explaining the seasons and the appearance of the moon.
-Visualization of how a year, a month and a day come to be.
-extra information for parents

The Jeffy-series let’s 6+ kids learn the stuff they want -or need- to know in a fun, interactive way. It helps parents to answer their children’s’ questions and enables them to play and learn together.

Jeffy’s Apps are created by Qlvr, a Dutch studio specialized in educational apps and serious games.

Meet Jeffy and his friends. Enter Jeffy's World!

Note: This app is meant to explain how the interaction of Earth, Sun and Moon cause our days, months and seasons to younger children. With that in mind certain simplifications have been made. In the upcoming update a few features will be added so that there can be no confusion that the angle of Earth's axis changes with respect to it's orbital plane, because of the movement around the Sun. (and that it's not tilting back and forth)

iPad Screenshots

(click to enlarge)

jeffy's World HD screenshot 1 jeffy's World HD screenshot 2 jeffy's World HD screenshot 3 jeffy's World HD screenshot 4 jeffy's World HD screenshot 5

App Changes

  • April 24, 2012 Initial release
  • June 18, 2012 New version 1.2
  • September 10, 2014 Price increase: $0.99 -> $1.99

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