In these apps for preschool and primary users, interactivity adds an extra-engaging aspect to learning new concepts.

The cute monsters from Endless Alphabet, Endless Reader, and Endless Numbers are back to teach basic Spanish vocabulary in Endless Spanish. A sight word beginning with each letter appears on the screen and is pronounced by the narrator, followed by a contextual sentence. A brief, humorous animation starring los monstruos explicates both the word's meaning and the gist of the sentence. In English translation mode, the narrator offers the English counterpart of the word/sentence, too. The silly monsters (and the funny situations they get themselves into) introduce vocabulary in an appealing way. Upbeat background music, sometimes with a bit of mariachi flavor, adds to the friendly feel. (Originator, 3–6 years)

The little girl and feline, respectively, stars of animated series Peg + Cat, have a series of loosely math-related, cat-stuck-in-a-tree adventures in The Tree Problem. First choose a location: Math-tropolis, Dino Valley, The South Pole, Broadway, The Farm, or Peg's Backyard. Then pick a level, one through five. Cat appears at the top of a tree (or treelike structure) on one side of the screen, Peg on the other. The goal is to manipulate the items that keep them apart (i.e., changing geyser levels, rolling snowballs) and make a safe passage for Cat to return to Peg. Peg and Cat keep up light banter throughout, including words of encouragement. (PBS Kids, 3–6 years)

In free-play app MarcoPolo Weather, users control weather, temperature, and day/night in a meadow, where three little anthropomorphic creatures play. Adjust these factors to create a wide range of conditions to which the animals — bunny Willow, bear Scout, and hippo Gorbie — and their environment respond. A toolbar offers various clothing, accoutrement (a flashlight at night, an umbrella in the rain, etc.), and food (picnic basket!) for outfitting the animals for the current conditions. A voiceover provides basic information on the meteorological conditions and how they are measured. Recommended weather-themed reading and suggestions for real-world activities are included. An engaging lesson about both weather and cause and effect. (MarcoPolo, 3–6 years)

Jump See Farm introduces life on several independent rural farms as well as an urban apiary. Each subject (pig, sheep, dairy cow, chicken, tractor, and bee) receives its own landing page featuring a naive-style illustration with a couple of interactive animations. Tap to access brief documentary videos that detail animals' jobs on the farm, their care and feeding, attributes of specific breeds, and how milk, cheese, honey, etc., are produced. The farm-working adults, kids, and teen 4-H members featured in the videos communicate the information with warmth and enthusiasm as cheery bluegrass music plays in the background. (JUMPSEEWOW, 3–6 years)

From the July 2015 issue of Notes from the Horn Book.