Explorations In Engineering : High Seas Adventure

PhET Density model Notes summarized from: (https://phet.colorado.edu/sims/html/density/latest/density_en.html) and reviewed by Aaron Weeden on 01/20/2022

Home screen =========== This is the screen you see when you first open the page. There is a heading "Density" with three images below it, each of which has a label below them. When an image or its label are clicked, a new screen opens. * "Intro" has an image of a wooden brown cube floating in water — this image and its label are bigger than the other two images. * "Compare" has an image with a yellow cube and a magenta cube floating in water. * "Mystery" has an image with a green cube with a question mark on its front face and which is on top of a measuring scale. Intro screen ============ At the bottom of the screen is a footer. In the bottom-left corner of the footer is the heading "Density." In the middle of the footer are four icons: a home icon (image of a house) which links back to the Home screen, and smaller versions of the three icons from the Home screen, each of which links to the same screens as they do on the Home screen. In the bottom-right corner of the footer is the PhET logo, which if you click on it brings up a menu with 6 options: "PhET Website," "Report a Problem," "Check for Updates," "Screenshot," "Full Screen," and "About." In the middle of the screen is a picture of the world: a blue sky, green grass, and a cross-section of the ground showing brown dirt below the grass. There is a hole in the ground filled with a 3D rectangular prism representing a tub of water (the top part of the tub is gray and the bottom water part is blue) — the level of the water is marked with a red triangle and a white label that says 102.00 L. Floating in the water is a brown wooden cube with a red label "A" and a white label 2.00 kg on its front. You can click and drag on the cube to move it around — as you do, the water level and the volume label change dynamically. You can drag the cube out of the water, and the volume changes to 100.00 L. If you drop the cube over the water, it falls in, bobs up and down, and settles. As this happens, the water level and volume label change dynamically. You can also drag the cube under the water, which changes the volume to 105.00 L, and if you let go, the cube rises to the surface and bobs up and down before settling. Again, the water level and volume label change dynamically as this happens. You can also drop the cube outside the tub on the grass to the left or right of the tub. In the top-middle of the screen is a collapsible panel labeled "Density (kg/L)," which contains a horizontal white ruler from 0 to 10 with tick marks labeled "Human," "Glass," "Titanium," "Steel," and "Copper." There is a red arrow pointing at a spot on the meter labeled 0.40 kg/L — this labels the density of the cube. In the top-right of the screen is a panel with some controls: * A selection menu labeled "A" with 6 options: "Styrofoam," "Wood" (chosen by default), "Ice," "Brick," "Aluminum," and "Custom." If you choose a different material type, the cube has the same volume but changes mass. * A horizontal slider labeled "Mass" with a default value of 2.00 kg that can be slid from 0.40 kg to 4.00 kg. The slider can be dragged in increments of 0.10 or there are left/right arrows that increment by 0.01. * A horizontal slider labeled "Volume" with a default value of 5.00 L that can be slid from 1.00 L to 10.00 L. The slider can be dragged in increments of 0.50 or there are up/down arrows that increment by 0.01. As the Mass and Volume sliders are slid, they also change each other's value, keeping the density of 0.40 kg/L constant. The sliders also change the size of the wooden cube that appears in the water. In the bottom-right of the screen are two buttons; one has a red cube (this one is selected by default) and the other has a red cube and blue cube. Clicking the second button adds a second cube labeled B to the tub, and the panels update to show that the cube is, by default, 2.70 kg/L, 13.50 kg, and 5.00 L — these can be changed just like cube A, and cube B can be moved around just like cube A. Incidentally, moving a cube into another cube knocks the second cube out of the way. Clicking the first button removes cube B. No matter the material, the min volume is 1.00 L, and the max volume is 10.00 L. Here are the range of possible masses for each cube material type: * Styrofoam: min 0.15 kg, max 1.50 kg * Wood: min 0.40 kg, max 4.00 kg * Ice: min 0.92 kg, max 9.19 kg * Brick: min 2.00 kg, max 20.00 kg * Aluminum: min 2.70 kg, max 27.00 kg * Custom: min 0.50 kg, max 10.00 kg — the Custom cube's color goes from black to gray as its volume is increased. In the bottom-right corner of the screen is an orange refresh icon that resets the model to a single cube with the default settings. Compare screen ============== This screen has the same footer. There is once again a tub of water in the middle of the ground, but there are no cubes floating in it. Instead, there are four cubes on the grass — two each on either side of the tub. They are all 5kg but different sizes. On the far right side is a small red cube; next to it on the left is a larger green cube. On the far left side is a larger blue cube, and next to it on the right is the largest cube, which is yellow. The cubes behave as before when you click and drag them. The panels that were on the Intro screen are no longer there. Instead, there is a panel in the top-right corner labeled "Blocks." It has radio buttons for "Same Mass" (selected by default), "Same Volume," and "Same Density." There is also a panel in the bottom-right corner labeled "Mass" that slides the mass from 1 kg to 10 kg in increments of 0.10 if you drag the slider or 0.01 if you click the left/right arrows. This slider changes the mass of all four cubes. The colors of the cubes get darker as their masses increase and lighter as they decrease. In the "Blocks" panel, changing to "Same Volume" changes the four cubes such that they are all the same size but, going from left to right, there is a dark yellow cube with a mass of 8.00 kg, a red cube with a mass of 2.00 kg, a blue cube with a mass of 6.00 kg, and a green cube with a mass of 4.00 kg. The slider changes to a Volume slider that goes from 1.00 L to 10.00 L in increments of 0.10 or 0.01. In the "Blocks" panel, changing to "Same Density" changes the four cubes such that, going from left to right, there is a blue cube with a mass of 2.00 kg, a yellow cube with a mass of 3.00 kg, a green cube with a mass of 1.00 kg, and a red cube with a mass of 0.50 kg. The slider changes to a Density slider that goes from 0.01 kg/L to 2.00 kg/L in increments of 0.10 or 0.01. There is also a refresh button in the bottom-right corner as before. Mystery screen ============== This screen has the same footer. Now there are again no cubes in the tub. On the left-side grass is a blue cube labeled 1B on top of a bigger purple cube labeled 1A. On the right-side grass is a yellow cube labeled 1C on top of a bigger red cube labeled 1D on top of an even bigger green cube labeled 1E. Cubes 1B and 1C appear to be around the same size, as do cubes 1A and 1D. 1E appears larger than all the other cubes. Also in the grass on the left is a measuring scale that reads 0.00 kg. Placing a cube on the scale changes the reading. Also, applying force by click and dragging the cube down onto the scale increases the reading. Releasing the cube brings the scale to a stable reading — 19.30 kg for 1A (purple), 0.40 kg for 1B (blue), 19.32 kg for 1C (yellow), 5.00 kg for 1D (red), and 2.80 kg for 1E (green). At the top of the screen is a collapsible panel, collapsed by default, labeled "Density Table" and with a table with headings "Material" and "Density (kg/L)." The rows of the table are: * Wood, 0.40 * Gasoline, 0.68 * Apple, 0.83 * Ice, 0.92 * Human, 0.95 * Water, 1.00 * Glass, 2.70 * Diamond, 3.51 * Titanium, 4.50 * Steel, 7.80 * Copper, 8.96 * Lead, 11.34 * Gold, 19.32 In the top-right corner of the screen is a panel labeled "Blocks" with the following radio buttons: * Set 1 (selected by default) * Set 2 * Set 3 * Random Changing the set changes which cubes are on screen. Each set is arranged the same as Set 1 by default (two cubes on the left, three on the right). Set 2 has the following cubes: * 2A: light brown: 18.00 kg * 2B: dark brown: 10.80 kg * 2C: light green: 2.70 kg * 2D: pink: 18.00 kg * 2E: purple: 44.80 kg Set 3 has the following cubes: * 3A: dark red: 2.85 kg * 3B: dark gray: 6.00 kg * 3C: light tan: 23.40 kg * 3D: dark yellow: 2.00 kg * 3E: light gray: 6.00 kg Random creates five random cubes in the same arrangement but with random colors and masses. There is also a button to regenerate a new random set of five cubes. It appears the random mass values range from around 0.83 kg up to around 200.00 kg. There is also a refresh button in the bottom-right corner as before.