Frilot Unit 1 & Unit 2 — Study Guide

Crissy’s creek (5 feet wide)

• Must be safe and easy to use, and she cannot get wet.
• Materials: only a rope and boards that are ten feet long.
• Best idea: tie the boards together to make a bridge.
• A sailboat, swimming, and swinging from a tree do not meet every criterion and constraint.

Artificial heart (last a long time)

Heart beats in thousands until wear showed:

The two that lasted longest: models A and B.

Knee-brace survey (100 people)

• Brace C is the best choice for comfort and support (highest percent).
• 42% is not a majority. A majority would be more than half.

Technology and risk

• The test’s example: cars cause some types of air pollution.
• The choice that pairs a technology with a real risk of that technology: computer games: less exercise.
• Cell phones are not matched with air pollution on this question. Light bulbs are not matched with wrist injuries. A dishwasher is not matched with “risk of disease.”

Maria’s shelves

• Best design: design 3 (yes and yes).
• When the prototype did not have room for every item, the best next step is add new criteria (not throw out the old ones, and not keep only the same criteria).

More design-process answers

• Tomato sunshade test: compare plants without a sunshade with plants with a sunshade.
• Sail fabric: stress the fabric with wind and weather over a period of time.
• Telling others about a machine that decreases air pollution: to help other people solve the same problem.
• Purpose of a prototype: to test a design and to see whether it meets design criteria.
• Scientists follow the design process to find solutions to problems.
• Conclusions about the birdhouse tool communicate whether the prototype met the criteria.
• Standards for how well a design does its job: criteria.
• Engineers test designs to find ways to improve their designs.
• Sasha’s paper airplanes (wings 10 cm, 20 cm, and 50 cm): after each flight, record how far each plane flew.
• An endoscope (plug, controls, camera) is technology.
• Dishwasher model B does not clean well: evaluate what is wrong and redesign it. Do not sell it anyway, and do not start the whole design over from zero.

Online traffic map

• Human need: a way to see traffic so people can get around.
• Legend: dotted = light traffic, dashed = moderate traffic, solid = heavy traffic.
• Near letter X: heavy traffic.
• People can use that information to go around X.

Bonus metric conversions

• 1 m = 1,000 mm, so 7.4 m = 7,400 mm.
• 100 cm = 1 m, so 12,500 cm = 125 m.
• 1 km = 1,000 m, so 3.2 km = 3,200 m.

Check: The handwritten answers on the bonus page were crossed out. 700 mm, 125,000 m, and 3 m are not the conversions.

What matter is

• Matter is anything that takes up space.
• As matter is added to an object, its weight increases.
• Air is made of particles that are very small and cannot be seen.
• To show air takes up space: blow up a balloon, tie it closed, and try to flatten it.
• On the pan balance, the soccer ball is lower, so the ball has more matter and more weight than the rock.
• A level balance (notebook and cubes) means the same weight.

Solid, liquid, and gas

• Solid (ice): has its own shape.
• Liquid (water): takes the shape of its container.
• Gas (water vapor): does not take up a definite amount of space and does not have a definite shape.
• Particle picture 1 (far apart): gas. Picture 2 (tight pattern): solid. Picture 3 (close, not in a tight pattern): liquid. The correct pair in the choices is 2: solid.

Properties and how they are measured

• A metal soup can: shiny, hard, reflective.
• An object that conducts electricity: a metal fork (not a foam cup, plastic knife, or wooden spoon).
• Solubility demo: pour salt into a glass of water.
• Volume of a rock: put the rock in water in a graduated cylinder.
• Weight: a balance.
• Sinead’s mineral: density 7.5 matches galena (pyrite 5.0, chromite 4.4, magnetite 5.1). Weight with a balance. Volume with a graduated cylinder with water.

Mixtures, solutions, and conservation of matter

• Sugar left outdoors in water: crystals and a little liquid. No new substances formed.
• Solutions on the numbered list: 1 and 4 — powdered sugar dissolves in water, and metals mixed into an alloy. Melting candy and burning paper are not solutions.
• Spaghetti (noodles, sauce, meatballs) is a mixture. The parts keep their identities.
• Cereal and milk: not a new substance, because the cereal can be separated to get the original substances back.
• Six cookies weigh 36 grams. Pushed into one ball they still weigh 36 grams.
• Oil 15 mL + vinegar 5 mL. Bars: oil 15 mL, vinegar 5 mL, salad dressing 20 mL (15 + 5 = 20).
• White powder stirred into water until the drink looks the same throughout is a solution (mixed evenly). It is not an alloy. Calling it only “a mixture whose parts keep their identities” was marked wrong on the paper because the even mix is a solution.
• After the water evaporates, the white powder is left.
• White crystals disappear in water and black flakes float: salt and pepper.

Bonus: baking soda and yeast

Vinegar stays 60 mL. Baking soda increases:

When more baking soda was added, a larger volume of gas formed. The vinegar amount did not change.

Yeast in hydrogen peroxide: 5 seconds 36°C some bubbles; 30 seconds 37°C more bubbles; 1 minute 38°C many bubbles. A chemical change caused the temperature to increase and more bubbles to form.