Exploring Science Math Technology
Media Travel

Discover a curated collection of my work to jumpstart your learning and to entertain you.

Find android apps including games, utilities, and math , engaging pre-algebra lessons, eye-opening travel videos, ready-to-use PowerPoint slides, and photos from around the world.

Get tools you can use to teach, create, and explore – all in one place! ALL FREE!

My Android Apps

I'd like to share some android apps I created. Here are math learning tools, utilities, and games (maybe not so helpful, but fun).

All my Android apps have been created using MIT App Inventor. If you like, you're welcome to the "aia" source files. Contact me.

All apps are available for direct download from my server. Details are listed below. Clicking on the image on the right will take you to Google Play Store for downloading those stored there.

("Long Click" on green buttons to begin download.)

Linear Explorer

Explore the slope intercept (y = mx +b) form of a linear equation. Drag the endpoints of the line section to see the equation, y intercept, x intercept, point coordinates.

The Mathtrap game. Use slope and y intercept numbers to enclose (trap) the moving mouse. Your score depends on whether you enclose the moving mouse inside a triangle of lines where you specify the slope and y intercept of each line.

Math Trap

Y = mx + b - Part 1


Play ths game - Experiment with Newton's Laws
Use the joystick to pilot your rocket acting under Earth's gravitational field. Without crashing into the Earth or having your rocket escape into space, navigate to a closed orbit close to Earth. Meanwhile, grab the satellite into your rocket. Release it to a tight orbit around the Earth.

Decimal to Fraction Explorer

Enter a decimal number < 1

Converts it to the nearest fractional

Shows representation as a pie chart



Decide what wrench to use for a nut/bolt by placing the head in the red hexagon, then manipulate the slider just cover it. Read the required wrench size in inches or centimeters. It can also be used to determine the size of drill bit for the correct hole.

Rocket Rangler

Enter your restaurant bill. Use TipRight to calculate the tip, add it to the bill, then divide it equally to share the cost.


Time events to the nearest millisecond. Synchronize your start time with other TwoTime users. Good for events where you can't see both the beginning and ending conditions, for example, a science experiment recording time taken to drop something from the roof.

Three apps in one.
1) Coin Toss
Touch or shake phone for heads/tails
Tracks throws / results H/T
2) Two Dice toss
Touch or shake phone
Tracks results
3) Random Items
Edit a list of items / Stored on device.
Touch button for random item on list
Built-in list of US states to try out

Y = mx + b - Part 2

L Block

The L Gsme is a two player game, played on a 4 x 4 square board. Each player has a 3 x 2, L-shaped block. Additionally there are two 1 x 1 pieces. One of these can be moved by the player.

The game is won by leaving the opponent unable to move their L piece without overlapping other pieces.

This is a card game originally developed for Chinese students at Shunde Technical College. The goal was to help them learn English words for over 100 common technical terms for items in mechanics, electronics, and basic physics.

Words are presented randomly. If the student says or enters the correct term the "card" goes away. If missed it can recur. The student "wins" when all of the cards are correctly answered.

Mecha 100

Prealgebra (GED) Math Review

Welcome to my Prealgebra video series !

This series is designed for students studying for :

  • 8th and 9th grade algebra,

  • a college prealgebra course

  • preparation for the GED math exam.

I cover all of the essential topics, including:

  • Arithmetic operations

  • Basic algebra concepts

  • Linear equations and inequalities

  • Polynomials

  • Rational expressions

  • Radical expressions

  • Quadratic equations

I am a passionate and experienced teacher, known for my clear and concise explanations. I will break down each concept step-by-step, and will illustrate with plenty of example problems.

If you are struggling with math, or if you are simply looking to brush up on your skills, this video series is for you. I will help you master the fundamentals of algebra, and will prepare you for success.

Here are some tips for getting the most out of this video series:

  • Watch the videos in order. This will help you build a strong foundation in prealgebra. (Each video is about 1/2 hour.)

  • Take notes as you watch the videos. This will help you remember the key concepts.

  • Pause the videos and try to solve the problems presented in the videos on your own. This will help you test your understanding of the material. Math is learned by doing problems!

I am confident that this video series will help you succeed in prealgebra. Good luck!

Students' Comments:

"I just pass may GED math by watching your videos. Thank you so much .You explain all The videos. I don't know more English But thank you god bless ."

"No exaggeration, this is the best math course online. Very clear illustration and explanation., also covers all the math topics."

"I finally understand the fundamentals of these problems after 30 year. Thank you Dr. Dan you blessed me!!"

"Thank you sir, you are very good teacher for percentage proportion i can use this. i was failed in math exam because i don"t know this I will apply again in the shipping company mostly of math exam of shipping company is what you"ve teached in video and fraction i have to study again math basic lol"

Watch as I transform a broken comfort dog and trakr tank into a unique and fun robot dog! Using an Arduino kit and Mit App Inventor, I created a controller app that lets my robot dog bark, say "who's a good boy", dance to music beats, and wag its tail.

This video was my submission for a "Stories For Change: The COVID Years Digital Storytelling," sponsored by Basic and Adult Education, Pima Community College. The workshop was presented by Creative Narrations. I served as a classroom aide. More examples may be seen at the Stories for Change website.



Images From Around the World

(Images will be updated regularly)